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 LIBRARIAN. 
 

 
BLACKS AND PITCHES 
 
OIL & COLOUR CHEMISTRY MONOGRAPHS 
 Edited by R. S. Morrell, M.A., Ph.D., FIC. 
 
 UNIFORM WITH THIS VOLUME 
 
 CELLULOSE ESTER VARNISHES 
 By F. SPROXTON, B.Sc., F.L.C. (British Xylonite Company). 
 
 IN PREPARATION 
 
 THE CHEMISTRY OF DRYING OILS 
 By R. S. MORRELL, M.A., Ph.D., F.L.C. (Messrs, 
 Mander Bros.), and H.R. WOOD (Messrs. Storey, Smithson 
 CS Co., Lids): 
 
 THE CHEMISTRY AND MANUFACTURE OF 
 
 PIGMENTS AND PAINTS 
 
 2vols. By C. A. KLEIN, M.Sc. (Brimsdown Lead Com- 
 pany), and W. G. ASTON (Messrs. W. Symonds & Co., 
 Ltd.). 
 
 THE PROBLEMS OF PAINT AND VARNISH 
 FILMS | 
 By H. H. MORGAN, Ph.D., B.Sc. (Messrs Naylor Bros., 
 Slough). 
 VOLATILE SOLVENTS AND THINNERS 
 
 By NOEL HEATON, B.Sc. 
 
 THE ANALYSIS OF PIGMENTS, PAINTS 
 
 AND VARNISHES 
 By J. J. FOX, O.B.E., F.LC., and T. H. BOWLES, 
 Ene 
 
 RESINS: NATURAL AND SYNTHETIC 
 
 By T. HEDLEY BARRY and R. $. MORRELL, 
 M.A., Ph.D., F.LC. 
 
OIL & COLOUR CHEMISTRY MONOGRAPHS 
 Edited by R. S. Morrell, M.A., Ph.D., F.L.C. 
 
 BLACKS & PITCHES 
 
 BY 
 
 H. M. LANGTON 
 M.A. (Cantab.), B.Sc. (London), A.I.C. 
 (Director, Messrs. J. B. Walker & Co., Ltd., Hull) 
 
 NEW YORK 
 
 D. VAN NOSTRAND COMPANY 
 EIGHT WARREN STREET 
 
 1925 
 

 
 
 
 Richard Clay & Sons, Ltd., Printers, 
 
 
 
 2 ‘ 
 : ; 
 we! 
 ‘ t 
 y 
 1 4 
 a 
 
PREFACE 
 
 In the following pages my endeavour has been to put before 
 the reader a concise account of our present knowledge of the black 
 pigments and of the various bituminous materials and pitches of 
 commerce. Whilst it may appear at a glance somewhat strange 
 to include in one and the same volume considerations of such 
 apparently dissimilar and unrelated classes of substances as Blacks 
 and Pitches, a little reflection will show the arrangement to be 
 justified. ‘These two classes of substances are of substantial 
 importance in a number of rather closely related Oil and Colour 
 Industries. Moreover, in passing, it is interesting to record that 
 the principal black pigment, carbon black, and the natural and 
 petroleum residual asphalts are traceable to a common .origin— 
 the petroleum fields. 
 
 From those chapters dealing with the black pigments it has 
 been thought preferable, for reasons which require no elaboration, 
 to omit all but a mere reference to the blacks which originate in 
 the synthetic dyestuffs industry. 
 
 The task of writing on bituminous materials and pitches is 
 rendered somewhat difficult by reason of the confusion still existing 
 on questions of nomenclature and classification, but without 
 entering fully into controversy, I have outlined a scheme of classi- 
 fication, mainly based on that given in Abraham’s well-known 
 treatise, ‘“ Asphalts and Allied Substances.” 
 
 An effort has been made to indicate as concisely as possible the 
 results of all the most important relevant investigations of recent 
 years and at the same time to refer briefly to current theories. 
 Though no claim to exhaustive treatment is made in the present case, 
 it is my hope that nothing of material importance has been omitted. 
 Suggestions are made as to the directions in which research may 
 usefully be undertaken, and it is hoped that the volume will prove 
 of service to many engaged in Oil, Colour, Paint, Varnish, Ink, 
 Rubber, and Asphalt Industries. 
 
 Every known source of information has been acknowledged in 
 the text, but my thanks are due particularly to the Bureau of 
 Mines, Geological Survey U.S. Department of the Interior, 
 Washington, for the supply of several official publications and much 
 statistical information, and for courteously permitting the repro- 
 duction of much textual matter and a number of illustrations from 
 Bulletin 192, on Carbon Black. My thanks also are due to the 
 Statistical Department of the Board of Trade for the supply of 
 data, to Mr. C. Ainsworth Mitchell for kindly loaning the blocks 
 
 Vv 
 
 ae eee 
 
v1 Preface 
 
 relative to Figs. 1 to 4, to Mr. A. R. Warnes for his kindness in 
 granting permission for the reproduction of Figs. 16 to 19, to 
 Messrs. Bennett, Sons & Shears, Limited, for the loan of the block 
 for Fig. 20, and to the British Engineering Standards Association 
 for authority to include several of their well-known British Standard 
 specifications. 
 
 To the publishers my thanks are extended for useful advice and 
 counsel and. for the care taken in the preparation of the text and 
 in the reproduction of the illustrations, whilst I am particularly 
 indebted to the editor for much useful assistance and criticism whilst 
 the book was in manuscript. My friend Mr. R. J. Whitaker has 
 kindly read through some of the chapters dealing with carbon 
 black. 
 
 Thanks are also tendered to my wife for much valuable assist- 
 ance in the tedious work of compiling tables and in the preparation 
 of the index. 
 
 For any inevitable errors of omission or commission the author 
 alone is responsible. 
 
 H. M. Laneton. 
 
 July, 1925. 
 
CONTENTS 
 
 2 PAGH 
 PREFACE : ; . ‘ ‘ ; ; : ; ; Vv 
 
 CHAPTER I 
 INTRODUCTION ; : : ; ; : : ; fe 38 
 
 System of Classification—General Occurrence and Methods of Prepara- 
 tion of Black Pigments. 
 
 CHAPTER II 
 GRAPHITE ' 4 : ; ‘ : : : ‘ ; 16 
 
 Occurrence in Nature—Manufactured Graphite—General Properties and 
 Uses in Manufacture of Lead Pencils and Graphite Paints. 
 
 CHAPTER III 
 
 THE Fixep CARBON BLACKS . j ; : ; : 22 
 
 Bone Blacks, Wood Charcoals and Mineral Blacks—Mode of Preparation 
 —Properties. 
 
 CHAPTER IV 
 Carbon BLAckK ‘ : | Z : ere 3 
 
 Its Manufacture from the Natural Gas of Petroleum Fields—Statistics— 
 Theory of its Formation—Commercial Methods of Manufacture by the 
 Channel Process, Rotating Disc Process, Plate Process, Roller Process 
 and by Thermal Decomposition—Attempts at Alternative Methods of 
 Production—General Properties and Analyses—Methods of Testing— 
 Uses of the Pigment. 
 
 CHAPTER V 
 
 LAMPBLACK  . : , , ’ ee 
 Methods of Production—Properties, Uses and Analyses. 
 
 CHAPTER VI 
 Buack PIGMENTS IN Paint MANUFACTURE : : é ees 
 
 Consideration of the Physical Properties Involved—Various Uses of 
 Black Pigment Paints—British Standard Specification for Carbon Black. 
 
 CHAPTER VII 
 
 Brack PigMENTS FoR INK MANUFACTURE : : ; ; 55 
 
 Different Classes of Work requiring Printing Ink—Properties of Blacks— 
 Long and Short Blacks—Chemical, Physical and Practical Tests on 
 Printing Ink Blacks—Some Photomicrographs of Ink Pigments. 
 
 CHAPTER VIII 
 CARBON BLACK AS A RuBBER PIGMENT . ; ; : me 
 
 Factors concerned in the Use of Compounding Ingredients in Rubber— 
 Tests for Carbon Black in Rubber—Change in Elastic Constants— 
 Stress-Strain Relationships. 
 
 vii 
 
Vili Contents 
 
 CHAPTER IX 
 PircHES AND Bituminous MATERIALS. : ‘ ; , 
 Introduction—Factors Involved in Classification—Definitions—Complete 
 Classification. 
 CHAPTER X 
 THE CHEMISTRY OF THE BITUMENS AND PITCHES . ; 
 
 Paraffinoid, Aromatic and Naphthenic Hydrocarbons—Nitrogenous, 
 Oxygenated and Sulphur Compounds, 
 
 CHAPTER XI 
 MetTuops oF TESTING Bituminous MATERIALS AND PITcHuEs 
 
 American and British Standardisation—Physical, Heat, Solubility and 
 Chemical Tests and their Uses. 
 
 CHAPTER XII 
 NATIVE ASPHALTS 
 
 Origin and Relationship to other Naturally Occurring Bituminous Bodies 
 —The Bermudez and Trinidad Pitch Lakes—Composition of Natural 
 Asphalts. 
 
 CHAPTER XIII 
 ASPHALTITES . 5 : : ; : E : ; 
 
 Gilsonite, Manjak and Grahamite—Their Occurrence and Characteristics 
 —The Asphaltic Pyrobitumens—Elaterite, Wurtzilite, Albertite, Imp- 
 sonite. 
 
 CHAPTER XIV 
 PETROLEUM ASPHALTS, OR RESIDUAL PITCHES . ‘ ; 
 
 Occurrence, World’s Production, and Refining of Petroloum—Charac- 
 teristics of Residual, Blown and Sulphurised Petroleum Asphalts. 
 
 CHAPTER XV 
 CoAL-TAR PitcH AND ALLIED PITCHES . : ; : hig 
 
 Residuals in Pyrogenous Distillation—Occurrence, Genesis and Com- 
 position of Coal—Destructive Distillation of Coal—Composition, Pro- 
 perties and Uses of Coal Tar—Coke Oven, Producer Gas and Blast 
 Furnace Tars—Distillation and Properties of the Resultant Tar Pitches. 
 
 PAGE 
 
 75 
 
 83 
 
 91 
 
 98 
 
 105 
 
 112 
 
Contents 
 
 CHAPTER XVI 
 MISCELLANEOUS PITCHEs . : ‘ : 
 
 Wood-tar Pitch fromy Hard and Soft Woods—Wood Distillation— 
 Rosin Pitch—Peat and its Distillation Products—Peat-tar and Lignite- 
 tar Pitches—Water—Gas and Oil—Gas-Tar Pitches and their Properties. 
 
 CHAPTER XVII 
 Fatry Acip Pircues : ; : ‘ 
 
 Subdivided into Stearine Pitch, Cotton Seed Pitch and Wool Pitch— 
 Saponification of Fatty Oils—Cotton Black Grease and Wool Grease— 
 Distillation Plant and its Operation—Characteristics of Various Stearine, 
 Cotton and Wool Pitches—Bone Tar Pitch. 
 
 . CHAPTER XVIII 
 
 Tue WEATHERING AND AGEING OF BiTruMINoUS MATERIALS 
 Effects of Exposure to Air, Sunlight and Moisture—The Light Sensitive- 
 ness of Asphalt. 
 
 CHAPTER XIX 
 BirumMINous Faprics ; 
 
 Roofing Felt—Floorings and Floor Coverings—Bituminous Cements, 
 Insulating Coverings and Papers—Waterproofing and Damp Coursing— 
 Manufacture and Uses of Bituminous Fabrics. 
 
 CHAPTER XX 
 Bituminous Paints, VARNISHES, ENAMELS AND JAPANS 
 
 Nature of Bituminous Bases Used—Volatile Solvents to be Used— 
 Bituminous Paints and Varnishes Protective against Rusting and 
 Exposure to Chemical Agents—The Jellying of Asphalt Paints—Japans 
 and their Uses—Pitting of Japans. 
 
 CHAPTER XXI 
 Bituminous PAvinec MATERIALS 
 
 Roadway and Pavement Construction—Surface Phenomena in con- 
 nection with Asphalt Pavement Construction—The British Standard 
 Specification for Tar and Pitch for Road Purposes. 
 
 APPENDIx I. 
 AprenpDIx II. 
 APPENDIX III . 
 INDEX OF NAMES . ‘ : : : : 
 
 INDEX OF SUBJECTS 
 
 129 
 
 138 
 
 142 
 
 151 
 
 164 
 
 171 
 173 
 174 
 175 
 176 
 
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 MARK MADE BY BORROWDALE GRAPHITE . . facing page 19 
 MARKS MADE BY FABER’S PENCIL. : as 19 
 MARKS MADE By ACHESON GRAPHITE PENCIL 2 19 
 Line In Drawine oF 1831 = 19 
 SELLING PRICE OF CARBON BLACK . : . 7, page: 28 
 
 CHANNEL PLANT IN COURSE OF CONSTRUCTION . facing page 31 
 
 METHOD OF CONVEYING CARBON BLACK .~ . . page 32 
 CARBON BLACK PLANT IN DETAILED PLAN ; . page 34 
 DEPOSITING SURFACE FOR CARBON IN THE RotTatTInG-DIsc 
 PROCESS ; : : : : ; . facing page 34 
 DETAILS OF THE PLATE OR CABOT PROCESS : = 34 
 THE ROLLER OR ROTATING CYLINDER SYSTEM . . page 36 
 ARRANGEMENT OF A LAMPBLACK PLANT . ; . page 43 
 PHOTOMICROGRAPH SHOWING AGGLOMERATED PARTICLES OF 
 SHORT CARBON BLACK . : : : . facing page 59 
 PHOTOMICROGRAPH SHOWING DISPERSED PARTICLES OF LONG 
 CARBON BLACK . i : ; ; . facing page 59 
 PHOTOMICROGRAPH SHOWING AGGLOMERATED PARTICLES OF 
 LAMPBLACK : : : : : . facing page 60 
 Pian oF Hirp’s Contrnvous DIsTILLATION PLANT . page I17 
 Hirp’s ContTINUOUS COAL-TAR DISTILLATION PLANT . wage 118 
 Hirp’s ContINvous CoAL-TAR DISTILLATION PLANT . page 120 
 
 Hirp’s Continuous CoAL-TAR DISTILLATION PLANT . ; 
 facing page 120 
 
 Fatty Acitp DISTILLATION PLANT . ; : = 132 
 
XX. 
 XXII. 
 XXII. 
 XXIII. 
 
 XXIV. 
 XXYV. 
 XXVI. 
 XXVIII. 
 XXVIII. 
 XXIX., 
 XXX, 
 
 LIST OF TABLES 
 
 PRODUCTION OF GRAPHITE 
 ANALYSES OF GRAPHITES : : : ; 
 COMPOSITION OF PIGMENTS IN ContTh’s PENCILS 
 
 YIELD OF CHARCOAL FROM AIR-DRIED Woop 
 
 RESULTS OF ANALYSES OF VARIOUS CHARCOALS 
 CARBON BLACK PRODUCED FROM NATURAL GAS 
 
 CARBON CONTENT AND QUANTITY OF CARBON BLACK 
 RECOVERED FROM NATURAL GAS . 
 
 ANALYSES OF CARBON BLACKS 
 
 ANALYSES OF CARBON BLACKS, LAMPBLACKS AND 
 OTHER BLAcKs (SELVIG) 
 
 ANALYSES OF CARBON BLACKS 
 ANALYSES OF LAMPBLACKS AND OTHER BLACKS 
 
 BuLKING VALUE AND Ol ABSORPTION OF SOME 
 PIGMENTS . ? ; : : : ; ; 
 
 PROPERTIES OF BLACKS . 
 CARBON BLACK AS A FILLER FOR RUBBER 
 
 Tuer RESULTS FOR MIXINGS CONTAINING 20 VOLUMES 
 oF PIGMENTS 
 
 OrIGIN, PuysicAL PROPERTIES, SOLUBILITY AND 
 CHEMICAL COMPOSITION IN CLASSIFICATION OF 
 PITCHES AND Brruminous MATERIALS . 
 
 TyprEs oF BITUMINOUS SUBSTANCES AND PITCHES 
 
 COMPLETE CLASSIFICATION OF BITUMINOUS SUBSTANCES 
 AND PITCHES 
 
 TESTS TO BE APPLIED TO BITUMINOUS SUBSTANCES 
 MaRrcusson’s SUBDIVISION OF ASPHALTS . ; 
 CoMPARISON OF SOME PETROLEUM DERIVATIVES 
 WoRrLp’s PRODUCTION OF PETROLEUM 
 
 PRINCIPAL REFINERY PRODUCTS FROM CRUDE 
 PETROLEUM i 
 
 RESIDUALS IN PyroGENovuS DISTILLATION 
 COMMERCIAL DISTILLATES FROM GAS WorKS TAR . 
 CHARACTERISTICS OF Various Tar PitTcHES 
 DISTILLATION PRODUCTS FROM PEAT 
 
 COMPARISON OF SOME RESIDUAL PITCHES : : 
 WaTER-GAS T'ARS : : - 
 
 ANALYSES OF Woon GREASES : 
 
 xi 
 
 63 
 
 68 
 69 
 
 72 
 84 
 96 
 98 
 106 
 
 107 
 113 
 115 
 119 
 125 
 127 
 127 
 135 
 

 
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BLACKS AND PITCHES 
 
 CHAPTER I 
 INTRODUCTION 
 
 System of Classification—General Occurrence and Methods of Preparation 
 of Black Pigments. 
 
 THE black pigments of commerce find use in the manufacture of 
 black paints and varnishes, in black printing inks, in stove polishes, 
 as compounding ingredients in manufactured rubber and in a 
 variety of other ways. With one or two exceptions, all the black 
 _ pigments contain carbon in one or other of its numerous forms as 
 their essential colouring principle, carbon being an ideal pigment 
 on account of its stability. It is unaffected by exposure to light or 
 air, is resistant to acids, alkalies and other chemical agents, and 
 suffers neither dissolution nor discoloration in contact with them 
 or in admixture with alcohols, oils, etc. It is destroyed only at — 
 high temperature when combustion ensues. Being usually in the 
 amorphous state, and finely divided at that, carbon pigments can 
 be readily compounded with the usual paint and ink vehicles, giving 
 extensive tinting and covering power, though these pigments vary 
 considerably amongst themselves in shade and strength and in 
 covering power. The carbon pigments can be mixed with other 
 pigments and the usual vehicles without causing any alteration in 
 them or being themselves altered, and as paints made from these 
 pigments are slow in drying, such paints require more than the 
 usual amount of driers. 
 
 A rational system of classification of the black pigments is some- 
 what difficult and the best is one, due to Cruickshank Smith,! which 
 takes into consideration both origin and method of production (see 
 page 14). 
 
 In this scheme of classification the term “‘ fixed ”’ is applied by 
 Cruickshank Smith to those carbon blacks in which the pigment is 
 “fixed ’” by an incipient coking process applied to suitable raw 
 _ materials, which are carbonised in a combustion chamber to which 
 a restricted access of air is permitted, and the pigment as produced 
 is retained within the combustion chamber. 
 
 It will be noted from the following list that a variety of blacks 
 containing elementary carbon exists, and unfortunately there is a 
 lack of precision sometimes in describing them; particularly is 
 this the case with carbon black and lampblack, it being often 
 quite erroneously assumed that these are alternative names for 
 
14 Blacks and Pitches 
 
 one and the same substance. Actually the various carbons and 
 charcoals have different physical and chemical properties, they 
 are varied in their physical structure and the uses to which they 
 can be put. They are not identical in chemical composition nor 
 are they pure carbon. 
 
 Black oe 
 
 Carbonaceous ) Metallic 
 | ee bias 
 Coloured by Compound Black Oxide Black Oxide 
 elementary (Lakes, inks of Iron of Manganese 
 
 carbon and dyes) (Fe,0,) (MnQ,) 
 Soe | 
 
 fl 
 
 
 
 __fNatural Graphite Fixed Carbon Deposited Carbon 
 
 | Artificial we Blacks or Soot Blacks 
 | 
 
 DOD) 9s 
 
 Vegetable Black 
 Mineral ,, 
 
 Carbon or Gas 
 Black, ete. 
 
 
 
 Ivory Black 
 = at Kes Black 
 
 Blue Re 
 Charcoal Black 
 (various) 
 
 The deposited carbon blacks are made by one or other of the 
 following methods, according to Roy. O. Neal ?: 
 
 1. Formation by direct contact of a flame upon a depositin 
 surface. eee 
 
 2. Production by combustion of an oil, tar, etc., in an inadequate 
 supply of air, where soot is allowed to settle slowly on the floors 
 and walls of the collecting chambers. 
 
 3. Carbonisation of solids and subsequent reduction to a state 
 of small subdivision. 
 
 4. Production by heating carbonaceous vapours or gases to a 
 decomposition temperature by external heating with or without 
 air in the forming chamber. This method is usually referred to 
 as cracking or thermal decomposition, and so far is only in the 
 experimental stage. . 
 
 Method 1 is that in use in manufacturing the typical carbon 
 black of the American trade, whilst method 2 gives rise to the 
 familiar lampblack whose first preparation and use are lost in the 
 depths of antiquity. The carbonisation method, of course, leads 
 to the production of all the familiar charcoals. 
 
Introduction 15 
 
 Graphite, in addition to being of natural occurrence, is also to a 
 certain extent artificially prepared in the electric furnace. 
 
 The compound carbonaceous blacks, the lakes and dyes, of which 
 the nigrosines may be cited as typical examples, have their genesis 
 in the synthetic dyestuff industry. 
 
 As regards the metallic blacks, their interest, so far as they enter 
 into the manufacture of inks and paints, is now mainly historical. 
 
 Black oxide of iron, Fe,O, (or FeO-Fe,0,), occurs in nature as 
 magnetite in many parts of the world. When pure it is an iron-black 
 substance used occasionally in some cheaper black paints and, in 
 admixture with other blacks, in certain cheaper qualities of printing 
 ink. 
 
 Black oxide of manganese occurs as pyrolusite (MnO,) in Czecho- 
 Slovakia, Spain, France and parts of N. America, in very pure 
 iron-black or steel-grey, rectangular, rhombic prisms, though often 
 as fibrous masses. Seldom is it, though, that it is found in the pure 
 condition—more often in association with other manganese ores. 
 When ground and finely powdered it is occasionally used as a pig- 
 ment under the name of “‘ manganese black.”’ 
 
 REFERENCES. 
 
 1 “ The Manufacture of Paint.’’ Scott, Greenwood and Son, 3rd edition; 
 1924. * “‘Carbon Black,” Bulletin 192, U.S. Dept. of the Interior, Bureau 
 of Mines, 1922. 
 
CHAPTER II 
 GRAPHITE 
 
 Occurrence in Nature—Manufactured Graphite—General Properties and 
 Uses in Manufacture of Lead Pencils and Graphite Paints. 
 
 GRAPHITE, known also as plumbago and blacklead, is a form of 
 carbon which occurs as a mineral widely distributed throughout 
 the world, generally in compact crystalline masses, but sometimes 
 in foliaceous, scaly masses and even sometimes in a fibrous form, 
 the variations being somewhat dependent on the locality. The 
 production for the past few years is given in the following table * :— 
 
 TABLE I. 
 Production of Graphite (Metric tons). 
 
 
 
 1921. 
 LFOPIOGINT 5, sake pasa mp oiaptee dae beks 30,000 
 AIMTGOC) ECAWOR non l san cse ues eeeera 2,346 
 CRTISGE LU Aiisibs natu teeaee 367 
 DEBBI ay sslec tor ak ok ae 3,088 
 Austria and Styria .........seeeee 10,800 
 Bohemia and Méahren ............ 8,500 
 BUT e ean cack ad oer sone aebitaat ee 3,000 
 COG ROE. 2 oss nnin ota Ca Teen ate Guananie 4,422 
 SPDR sip boixansiecuas vais meee er ee 950 
 REIIIOOM as. os cacao ket Vikas ao ealera deieeies 11,000 
 DEAGAGEROAN ois lies vatenscadaenhnee — 
 Other COUNETICS ........cc0cesccccees —- 
 
 TL Ota St kictk ts ccaesore te oeeerbest 85,000 100,000 136,498 
 
 In England, graphite was found at Borrowdale in Cumberland 
 as far back as 1560, but the supply is practically exhausted there.* 
 The best qualities are now found in Ceylon, whereas the poorer 
 qualities occur in Sweden and Bavaria, the ash in specimens from 
 these sources being sometimes 40—60%. In the U.S. the quan- 
 tities are often insufficient to make it worth while to work them in 
 some localities. 
 
 Graphite is velvety-black or steel-grey in colour with metallic 
 lustre, is opaque, quite soft to the touch, and makes a grey mark 
 on paper. It crystallises in small hexagonal plates, though it also 
 occurs amorphous, and it is then sometimes difficult to distinguish 
 sharply between graphite and the usual amorphous charcoal forms 
 of carbon. The specific gravity varies from 2-25 to 2-35 when pure. 
 The principal impurities with which it is found in association are 
 
 ferric oxide, alumina, silica and lime, the carbon being present to 
 16 
 
Graphite hy 
 
 the extent of 75—92%. For purification it is crushed and levigated 
 and subsequently the ash content reduced by chemical treatment. 
 
 A certain amount of graphite is now manufactured by the 
 International Acheson Graphite Company at Niagara Falls, U.S.A., 
 the amount having been about 3700 tons in 1920. This manu- 
 facture is due to an observation by E. G. Acheson that carborundum 
 at a temperature above 2000° C. is decomposed into carbon and 
 silicon, the former being in the form of crystalline graphite. He 
 subsequently observed that coke could be converted into graphite 
 in the presence of much less silica than would be required to convert 
 the whole of the carbon into silicon carbide, and he therefore con- 
 cluded that the action was catalytic. It is now known that all 
 forms of carbon can be converted into graphite under suitable 
 conditions of temperature, though the rate at which this occurs 
 varies greatly with conditions and with the nature of the reactants. 
 
 At present graphite is manufactured by the Acheson Company, 
 according to H. D. K. Drew,°® by the following U.S. Patents: 
 542,982 of 1895; 568,323 of 1896; 617,979 of 1899: 645,285 of 
 1900; 702,758 of 1902, and 711,103 of 1903. For graphite powder 
 a furnace similar to that favoured in carborundum manufacture is 
 adopted. : 
 
 Carborundum is used in constructing the furnace walls, the 
 end-walls through which the electrodes pass being fixed and the others 
 movable. The furnaces, which may be 30 ft. in length and of 
 sectional area 18 ins. by 14 ins., contain a charge of clean anthracite 
 in fine powder containing up to 10% ash, packed round a core of 
 graphitised coke. Petroleum coke is used for making the best 
 qualities of graphite. A current of 3000 amperes at 220 volts is 
 first passed, but later, as the resistance decreases, the final current 
 is 9000 amperes at 80 volts, the duration of the operation being 
 about 24 hours, after which the graphite is cooled, removed, and 
 ground in tube mills, and by air separation the fine material sifted 
 from coarse particles. 
 
 Manufactured graphite in addition to containing 1—2% of 
 amorphous carbon may contain up to 10% of ash, though in the 
 case of the purest form the ash is no more than 0-:2%. 
 
 A method for the rapid analysis of graphite has been described 
 by G. B. Taylor and W. A. Selvig,® but space forbids a description 
 here. 
 
 Uses. 
 
 Natural graphite is mainly used for the manufacture of plumbago 
 
 oe 75% of the total supply being absorbed in this way; ’ 
 
18 Blacks and Pitches’ 
 
 the remainder is accounted for by lubricants 10%, pencils 7%, 
 foundry work 5%, paints 3%. Artificial graphite finds its use for 
 electrodes, lubricants, paints, dry batteries and in boiler-scale 
 preventives. 
 
 Its uses in the manufacture of crucibles, electrodes and foundry 
 work are outside the scope of the present volume, though brief 
 reference may be made to its use as a lubricant. Flaked graphite 
 can be used dry in steam cylinders, and it is said to build up a 
 surface on rough bearings; it is sometimes compounded with 
 compound greases for heavy bearings and with lubricating oils for 
 light bearings. Its lubricating properties in colloidal suspension 
 have been discussed by H. L. Doyle * and a method of deflocculating ' 
 graphite has been patented by E. G. Acheson.® The fact that 
 colloidal graphite is, however, very susceptible to the flocculating 
 action of electrolytes, less than 0-1°% of free fatty acids being sufficient 
 to precipitate it, would appear almost to inhibit its use in this way. 
 
 It is well to remember in mentioning the lubricating pro- 
 perties of graphite that both it and the diamond are crystalline 
 forms of the element carbon: the former soft and greasy to the 
 touch, the latter one of the hardest substances known and in 
 powdered form strongly abrasive, in striking contrast to the lubri- 
 cating character of its graphitic allotrope. The new method of 
 X-ray analysis has given the clue to these striking differences in the. 
 two allotropes, differences which must be accounted for by differences 
 of molecular structure. 
 
 A full account of graphite as a lubricant is given in a memoran- 
 dum on Solid Lubricants in the Report of the Lubricants Com- 
 mittee,/° to which the reader is referred for full information. 
 
 Graphite has no great use as an oil or varnish colour except in 
 the manufacture of anti-corrosive paint for use on ironwork, and 
 according to Zerr, Riibencamp and Mayer !! is used exclusively in 
 many parts of Europe for blackleading iron stoves, its fire-proof 
 properties rendering it very suitable, and in the painting of sheet 
 iron as a preventive against rust. The manufactured graphite 
 when finely ground is similarly used as a paint. According to 
 H. A. Gardner,!” graphite gives a better paint coating when mixed 
 with other pigments, such as red lead and sublimed blue lead. He 
 points out the great tendency in graphite towards agglomeration 
 of particles. In addition to being proof against rusting, graphite 
 in a paint imparts immunity against the corrosive action of gaseous 
 sulphur compounds, ammonia, the halogens and their gaseous 
 derivatives, etc. 
 
A 
 
 
 
 >, 
 
 
 
 x 
 we wes 
 y 
 
 
 
 
 
 
 
 “Kate np tctM akes 
 Sg .. 
 
 ow 
 
 
 
 
 
PHOTO-MICROGRAPHS OF PENCIL MARKINGS 
 
 
 
 Fig. 1.—Mark made by Borrowdale Fic. 2.—Marks made by Faber’s 
 
 Graphite used for Pencil-making in Pencil. Striations show sequence of 
 1851. Now in Geological Museum. lines. x~20. 
 x 20. 
 
 
 
 Fia. 3.—Marks made by Acheson Fic. 4.—Line in Drawing of 1831. 
 Graphite Pencil. Striations show Typical of old pencil markings. 
 sequence of lines. xX 20. x 20. 
 
Graphite 19 
 
 The most important use to which graphite is put with which 
 we are concerned here is in the manufacture of black-lead pencils. 
 According to Ainsworth Mitchell,* the graphite of Borrowdale was 
 used from the time of its discovery, about the year 1560, until the 
 latter half of the nineteenth century for the manufacture of the pencils 
 used throughout Europe. An account of the properties and uses 
 of graphite in this connection is given by Cesalpinus,!* though 
 apparently the true nature of graphite was not known until 
 demonstrated by Scheele in 1779. 
 
 About 1840, when the Borrowdale mine was becoming exhausted, 
 efforts were made to utilise the accumulations of graphite dust, 
 and a patent was taken out by Brockedon,“ according to which 
 finely-sifted graphite was induced under great pressure into the 
 form of compact blocks which could be sawn up in the usual way. 
 About the middle of the last century, however, the composite 
 pencil was coming into use, having first originated with Conté, of 
 Paris, in 1795. 
 
 In Conté’s process finely elutriated clay and graphite are mixed 
 to a paste forced through dies in a cylinder, and the circular threads 
 of pigment dried, heated in a covered crucible and afterwards 
 fixed into the grooved wooden holders with which we are familiar. 
 Since that time such developments as the incorporation of wax, 
 lampblack, resin, etc., with the pigment have arisen. 
 
 According to Mitchell,* the suitability of graphite for pencil- 
 making depends, from a chemical aspect, on: (1) the proportion 
 of carbon, (2) the amount of silicates, (3) the iron. Moreover, 
 the physical nature of the carbon in the graphite appears to be 
 of importance, and this is borne out by microscopical examination 
 of marks produced on paper by graphite. In the microscopical 
 examination, both vertical and horizontal lines are recommended 
 by this author to be examined, using a 1 in. objective and with a 
 strong side light. Under these conditions, in the case of Borrowdale 
 graphite, the vertical lines show relatively few straight striations, 
 and when these occur in the heavier strokes they are disjointed 
 and irregular. 
 
 Table IL gives the results of some analyses of graphite due 
 to Mitchell,* by whose courtesy also it is possible to reproduce the 
 photomicrographs he prepared. 
 
 For an account of the method of analysing pencil pigments the 
 reader must consult the original paper. 
 
 Marks made by pure graphite, when examined under the micro- 
 scope in a vertical position with illumination at right angles, show 
 
Blacks and Pitches 
 
 20 
 
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Graphite 21 
 
 irregular silvery strokes or broken striations. In the modern pencil 
 pigments, in which clay is incorporated with the graphite, fine 
 beaded striations parallel and uniform throughout the pencil mark 
 appear. An examination of Figs. 1, 2, 3 and 4 enables these 
 differences to be appreciated. 
 
 Mitchell * has also given the composition of a number of pencil 
 pigments made by the Conté firm, reproduced below : 
 
 TABLE III. 
 
 Composition of Pigments in Conté’s Pencils. Series 1020. 
 
 3 Loss at 
 ae Graphiti 200-210° C. Iron oxide 
 a aan Silicates. | with traces Remarks. 
 & ‘ Wax, of Al,O3. 
 a etc. Ash. 
 % % Yo % % 
 0 60-28 12-85 26-87 23-70 2:07 Puce-coloured ash 
 1 55:43 17:71 26-86 16-54 5-93 2 
 2 57:63 13-76 28-61 25-61 1-90 © 
 3 50-80 10-60 38-60 34:95 0-28 “a 
 4 48-52 12-21 39-27 34:98 3-79 a 
 5 36°06 8-4] 55-53 36-29 5-35 Titanium present 
 REFERENCES. 
 
 3 J. Soc. Chem. Ind., 1922, 44,246r. 4 C. Ainsworth Mitchell, ibed., 1919, 
 38, 3837. °® Martin, “‘ Industrial Chemistry,” Vol. IT., 1918, Section LXXXVI, 
 - 404. &® Bulletin 112, U.S. Bureau of Mines, 1920, 43. 7 J. Soc. Chem. Ind, 
 1920, 356r. °® Journ. Phys. Chem., 1913,17, 390. °% U.S. Patent 1,223,350 of 
 1917. 4° ‘‘ Report of the Lubricants and Lubrication Inquiry Committee,”’ 
 Dept. of Scientific and Industrial Research Advisory Council, H.M. Stationery 
 Office, 1920. 11 ‘‘Colour Manufacture,’’ Charles Griffin, London, 1908. 
 12 “Paint Technology and Tests,’ 1911. 3% “De Metallicis,’’ Libri Tres, 
 Paris 1602, Cap. VII, 186. 44 English Patent 9977 of 1843. 
 
 Bibluography—Graphite. 
 
 Electro-Chem. and Met. Ind., 1902, 1, 52; 1905, 3, 253; 1907, 5, 452. 
 Met. and Chem. Eng., 1911, 9, 536; 1913, 11, 242. Trans. Amer. Electro- 
 chem. Soc., 1902, 1, 53; 1902, 2, 43; 1907, 12, 29; 1911, 20, 105. A. J. 
 Allmand, ‘“‘ The Principles of Applied Electro-Chemistry,’’ London, 1912. 
 J. Wright, “ Electric Furnaces and their Industrial Applications,’’ London, 
 1910. ‘‘ Graphite, its Occurrence and Uses,”’ Bulletin Imp. Inst., London, 
 1906, 4, 353. H.S. Spence, ‘“‘ Graphite,” Dept. of Mines, Ottawa, Publica- 
 tion No. 511, 1920. J. G. Bearn, “ The Chemistry of Paints, Pigments and 
 Varnishes,”’ Ernest Benn, 1923. Thorpe, ‘‘ Dictionary of Applied Chemistry,” 
 1921-1924. J. W. Mellor, ‘“‘ Inorganic and Theoretical Chemistry,” Vol. V., 
 Longmans & Co., 1924. F. Cirkel, ‘‘ Graphite, its Properties, Occurrence, 
 Refining and Uses,’’ Ottawa, 1907. 
 
CHAPTER III 
 THE FIXED CARBON BLACKS 
 
 Bone Blacks, Wood Charcoals and Mineral Blacks—Mode of Preparation— 
 Properties. 
 
 THE basis on which the blacks, described in this chapter, are differen- 
 tiated from other black pigments has been mentioned along with 
 their general method of preparation in the introductory chapter. 
 Leaving out of consideration the mineral blacks, the “ fixed ’’ carbon 
 blacks are known perhaps more familiarly as the charcoal blacks, 
 and they all have the same genesis. When non-volatile carbon- 
 aceous substances are heated in closed retorts or kilns out of contact 
 with air, such substances undergo decomposition, and water, certain 
 volatile carbon compounds, such as carbon dioxide, carbon monoxide, 
 acetic acid, acetone, hydrocarbons, and certain oily, tarry or resinous 
 compounds result, and a residue of elementary carbon, associated 
 with a greater or lesser amount of mineral ash, remains behind in 
 the retort. The amount and nature of such elementary carbon or 
 charcoal remaining depend on the nature of the raw material, the 
 type of plant used, the temperature at which the operation is carried 
 out and the extent to which volatile decomposition products are 
 removed from the sphere of action. This method of producing 
 charcoal blacks is termed dry distillation. 
 
 A convenient subdivision or classification of the black pigments 
 to be reviewed here is the following : 
 
 (a) Bone Blacks, including ivory black and drop black. 
 
 (6) Wood Charcoals, including vegetable charcoals and vine 
 black. 
 
 (c) Mineral Blacks. 
 
 This subdivision serves to indicate the origin of the black, and 
 to some extent is further justified by some of the characteristics 
 exhibited by these various blacks. 
 
 (a) Bone Blacks.—These are made by calcining bones in air- 
 tight retorts, the bones being previously freed from adhering fat 
 and ground to a coarse powder and sifted. During calcination, 
 when black for pigment is the primary need, the products of com- 
 bustion are burned instead of being recovered, the claim being that 
 a better product results, but this is purely conjectural. At any 
 rate, the bone black so prepared has greater colour-strength and 
 better working qualities than sugar-house black, where, during the 
 calcination, the by-products of the dry distillation are suitably 
 
 recovered, and the black is obtained in a granular form. After 
 22 
 
The Fixed Carbon Blacks 23 
 
 being used in sugar filtering, it is washed, ground wet, dried and 
 afterwards finds use as a paint pigment under the name of Drop 
 Black. 
 
 If bone black be treated with acid and the calcium salts dissolved, / 
 a finely-grained carbon almost free from ash results. Acid-washed 
 black has a very deep black colour, and in consequence of its fine 
 state of division a great deal of colour-strength. 
 
 Ivory black is a form of bone black made, not, as formerly, by 
 charring the waste cuttings of ivory, but by the dry distillation of 
 the best quality of bones obtainable after defatting, etc. Ivory black 
 is more intense in blackness than the average quality of bone black. 
 
 A very important use for bone black is as a decolorising agent 
 and deodorant in the filtering of sugar and other solutions and oils; 
 although it is outside the scope of the present volume to discuss the 
 utility of bone black in this direction, reference may be made to 
 the recent work of P. M. Horton and W. D. Horne,!* on the 
 réle played by bone black (or animal charcoal, as it is sometimes 
 termed) in decolorising. It is interesting to note, however, 
 according to Oliver Wilkins,’ that much of the bone black used 
 as a pigment comes second-hand to the colour manufacturer from 
 the sugar refiner. The “spent” animal charcoal of the latter is 
 thoroughly washed and ground by. heavy stones to reduce the 
 spongy, carbonaceous matter to a fine, silky powder. According 
 to this author, the old custom was to sell this black in lumps made 
 by dropping the black paste, as it came from the levigating stones, 
 in little heaps on to boards for drying, and the following out of this 
 prescribed ritual and the production of the black in peculiarly 
 shaped pieces was a criterion of purity. To some extent even 
 to-day this procedure has to be adopted in order to satisfy those 
 users who are unconvinced of the purity of finely-ground bone black 
 sold in the form of a powder. 
 
 Generally speaking, the various bone blacks are denser than 
 carbon and lampblacks. They are of bluish-black colour, have a 
 specific gravity of 2-6 to 2-80 usually, and are characterised by a 
 high content of ash, often as high as 80% or upwards, with a corre- 
 spondingly low carbon content, which may be as low as 10%, the 
 ash being largely calcium phosphate. 
 
 (6) Wood Charcoals.—The old-fashioned method was to carbonise 
 wood in heaps, taking care that access of air was very restricted, 
 but the method had many disadvantages, and owing to lack of 
 proper control of air supply, temperature, etc., it was impossible 
 to manufacture a product of uniform composition and of guaranteed 
 
24. Blacks and Pitches 
 
 purity. Ultimately, therefore, the method of heating in retorts 
 or air-tight crucibles was resorted to, as in the manufacture of bone 
 black. 
 
 The subject has been reviewed by T. W. Pritchard,1® who refers 
 to the old destructive distillation process carried on in a series of 
 retorts fitted with condensers set in brickwork, under which was a 
 furnace. Temperature control is an important feature of the 
 operation. This process gave a high yield of products. 
 
 Later, the process of subjecting to steam distillation wood rich 
 in resins and turpentine was resorted to before commencing 
 carbonisation. 
 
 A modern process, followed in the United States, and termed the 
 solvent process, is to take pine wood, which is shredded and then 
 extracted by means of solvent naphtha, which removes in good yield 
 the turpentine and resins, which are recovered after removal of the 
 solvent. Subsequently the extracted wood is carbonised. 
 
 The yield of charcoal from wood depends, of course, on the 
 nature of the wood carbonised and on the way it is heated. G. 
 Martin ® has given some statistics illustrative in this connection of 
 the yield of charcoal from air-dried wood, viz. :— 
 
 TasueE IV. 
 Yield of Charcoal from Air-dried Wood. 
 
 Nature of wood. Charcoal yield %. 
 Beech slowly heated .........cseeceaes 26:7 ) 
 “f QUICHE Eh oe icc nteh cy eee “21-9 
 Oak slowly heated ..........ccsee0e 34:7 
 = WIGHT. 30. cudotadetes eens 27-7 
 Birch slowly heated ..........cccesees 29-2 
 ¥ Cg neta eee 21-5 
 Pine slowly heated ......,....ccce00 30:3 | 
 2 QUICKIES vo cai5 ccd eeas abe eereneee 24-2 
 
 Besides the resinous woods, such materials as sawdust, coconut 
 shells, cork cuttings, beech twigs and leaves and similar vegetable - 
 matter are carbonised, particularly for the production of vegetable 
 charcoal, though for the true vine black, now largely of historic 
 interest, vine twigs, grape husks and washed wine lees are carbonised. 
 
 The apparent specific gravity of the various charcoal blacks 
 varies from 0-106 to 0-206, but when air-free they have a real specific 
 gravity of about 1:8. With the exception of vine black, none of 
 them has any great colour-strength, though they are used mixed 
 with other black pigments. 
 
The Fixed Carbon Blacks 25 
 
 In the table given below are the results of analyses of a number 
 of bone, wood and other charcoals examined in the author’s labor- 
 atory 1*« during the past four years. 
 
 TABLE V. 
 
 Results of Analyses of Various Charcoals. 
 
 Volatile Fixed 
 
 Material. Moisture. Ash. mietbae. east. 
 > (a) Oo oO oO 
 O oO Oo Oo 
 
 Boome black 2. cicescscccsesss vee Oe Ae id ba 
 A SS | Se 3°35 78-52 8°86 9-27 
 Vegetable charcoal I ...... 3°70 3°35 6-70 86-25 
 
 a rs 17 ee Sees 6°57 3:40 6°78 83°25 
 
 2 ae) 6s oe 6:49 4-42 10-71 78°38 
 
 ie ato od" Sate naee 5-30 4-50 9-28 80-92 
 Willow charcoal ............ 3-26 2:10 13-66 80-98 
 
 With the exception of the bone blacks, none of the above was of 
 intense black colour. The bone blacks were high in ash content and 
 their texture was not so fine as that of the other blacks recorded 
 above. Some of the vegetable charcoals were particularly fine, 
 having almost the fluffy texture of a typical American carbon 
 black. 
 
 (c) Mineral Black.—This is a black pigment made by grinding 
 a black form of slate or clay shale which has a carbon content of 
 about 30%. This shale exists widely distributed, occurring in a 
 specially pure state in Spain, less so in Switzerland, the Tyrol and 
 Italy, and is generally blue-black to brownish-black in tint. 
 
 Certain so-called mineral blacks are also produced, similar to 
 the above in character, by carbonising in retorts waste coal dust and 
 Scotch boghead mineral, the charred mass containing up to 30—40% 
 of carbon. 
 
 According to Gardner,!* mineral black, owing to its low carbon 
 content, has only a low tinting power, though it finds use as an inert 
 pigment in compounded paints. It has a flocculent appearance, 
 the particles showing a strong tendency to mass. 
 
 REFERENCES. 
 
 15 P, M. Horton, J. Ind. Eng. Chem., 1923, 15, 519. 18 W. D. Horne, 
 ibid., 1922, 14, 1134. 17 “The Manufacture and Properties of Pigments 
 for Paints,’? Oil and Colour Trades Journal, April 25th, 1924, p. 1165. 
 18 “ Recent Developments in Wood Distillation,” J. Soc. Chem. Ind., 1912, 
 418. 1918, p. 325. 18 Unpublished results. 
 
26 Blacks and Pitches 
 
 Bibliography—Bone, Charcoal, and Mineral Blacks. 
 
 B. E. R. and J. A. R. Newlands, J. Soc. Chem. Ind., 1888, 7, 419. T. L 
 Patterson, 2id., 1903, 22, 608. C. H. Hall, J. Ind. Hng. Chem., 
 1922, 14, 18. G. Barfi, German Patent 168,034 of 1904. F. E. Bartell and 
 E. J. Miller, J. Amer. Chem. Soc., 1922, 44, 1866; 1923, 45, 1106. J.C. 
 Lawrence, J. Soc. Chem. Ind., 1918, 87, 7. H. K. Benson and L. L. Davis, 
 J. Ind. Eng. Chem., 1917, 9,!141. Thorpe, “‘ Dictionary of Applied Chemistry,” 
 1921-1924. ‘“‘The Utilisation of Wood Waste by Distillation,” Harper, 
 St. Louis, 1908. ‘Production of Bone Black.” W. Jones, U.S. Patent 
 1518072 of 1924. 
 
CHAPTER IV 
 CARBON BLACK 
 
 Its Manufacture from the Natural Gas of Petroleum Fields—Statistics— 
 Theory of its Formation—Commercial Methods of Manufacture by the 
 Channel Process, Rotating Dise Process, Plate Process, Roller Process 
 and by Thermal Decomposition—Attempts at Alternative Methods of 
 Production—General Properties and Analyses—Methods of Testing— 
 Uses of the Pigment. 
 
 CaRBON black is the fluffy, velvety-black pigment produced in the 
 
 form of an impalpable powder by the burning of natural gas against 
 
 a metal surface. This black is not to be confused with lampblack, 
 
 from which it differs in several respects, and which is made by 
 
 entirely different methods. According to G. L. Cabot,!® who is 
 one of the pioneers of the American carbon black industry, certain 
 printing-ink makers of New York and Philadelphia found that the 
 
 soot, deposited by the suitable burning of artificial gas, gave a 
 
 beautiful gloss and an intense tint to printer’s ink, differing in both 
 
 these respects from the older and more familiar lampblack. 
 
 The first recorded use of natural gas for lighting purposes in 
 the U.S.A. occurred as far back as 1826 in New York State, but it 
 was only in 1872 that its general use for domestic purposes came 
 about, the gas being conveyed along pipes from the gas wells of the 
 petroleum fields. The same year saw the erection at New Cumberland 
 of the first factory to manufacture carbon black on a commercial 
 scale.2 In this factory gas from a gas-holder passed through 
 pipes to gas-jets arranged in the same horizontal plane beneath 
 slabs of soapstone that were pierced with numerous orifices, through 
 which excess smoke and waste gases passed. Over the slabs was a 
 roof provided with dampers for controlling ventilation. Transverse 
 horizontal scrapers below the slabs were supported, and moved 
 in horizontal grooves in the lower and opposite sides of the roof, 
 the scrapers from time to time removing the carbon black deposited 
 by the burning of the gas. The carbon black fell into sheet-iron 
 troughs suitably supported. The depositing surface was kept 
 cool by an arrangement dependent on continuously circulating 
 water. 
 
 The first lot of 500 lbs. of carbon black marketed sold for $2.50 
 per lb., but by 1881 the price had fallen considerably, and 
 the movement in the selling price since then is indicated by the 
 chart 2 (Fig. 5). Whereas the total production in 1881 was pro- 
 bably only 400,000 to 500,000 lbs., by 1920 it had risen to about 
 50,000,000 lbs. 
 
 Since the early establishment of the carbon black industry 
 
 27 
 
28 Blacks and Pitches 
 
 numerous innovations have been introduced and considerable 
 advances made in the methods of manufacture. The extent and 
 
 60 
 
 50 
 
 ee 
 
 
 
 Pa 
 es 
 Pe 
 pee 
 
 
 
 
 
 
 
 
 
 Cents per Found. 
 bo 
 s} 
 
 
 
 
 
 
 
 
 
 ® 
 
 yeahs 
 Fic. 5.—Selling Price of Carbon Black. 
 
 value of the industry are best gathered from the following table, 
 due to E. G. Sievers 7°: 
 
 TaBLe VI. 
 Carbon Black Produced from Natural Gas. 
 
 Average 
 N Quantity Average vine teq Quantity of 
 meted produced Value $. aa black per; gas used 
 (Ibs.) icon 1000 e. 
 
 
 
 ———— | |) | | 
 
 
 
 1919 
 West Virginia ... 23 | 29,925,614} 2,358,119 79 | 1:3 23,117,332 
 Louisiana ......... 7 | 14,024,606 933,334 6-7 | 0-7 20,291,021 
 Wyoming ......... ; : 
 a. ee 2 4,868,947 231,747 4-8 | 1-1 4,306,153 
 Oklahoma. ...... : , 
 Ranhisles) 2 2,922,274 244,726 8-4 | 1:5 1,954,029 
 Pennsylvania ... 2 315,500 48,114} 15-3 | 1-4 227,700 
 36 | 52,056,941} 3,816,040 7:3 | 1:04 | 49,896,235 
 1920 
 West Virginia ... 19 | 26,659,469] 2,221,674 8-3 | 1-43 | 18,628,780 
 Louisiana ......... 15 | 18,565,498! 1,455,764 78 | 1:0 18,099,800 
 Wyoming ......... ] 
 Montana ......... 1 5,850,313 326,424 5-6 | 1:6 3,673,108 
 Kentucky ...... ie ue 
 Pennsylvania ... 2 246,612 28,424 | 11:5 | 1-2 197,290 
 
 eS) — SS | — | | 
 
 39 | 51,321,892| 4,032,286 7-9 | 1-26 | 40,598,978 
 
Carbon Black 29 
 
 The variation in the average yield of carbon black per 1000 c. ft. 
 of gas burned is indicated in these figures. It must be remembered 
 that there are considerable variations in the price of gas in the 
 different fields. The industry is necessarily a migratory one— 
 gas may become prohibitive in price in a particular district or 
 the supply may become intermittent or fail altogether. 
 
 In selecting the location of a plant, an idea of the ultimate supply 
 of gas available should be obtained by reference to rock pressure, 
 thickness of gas-bearing strata, porosity of the sands, the presence 
 or absence of intruding waters, and some knowledge of the previous 
 _ history of the field and of the drilling which has been practised. 
 The following summary, due to R. O. Neal,?! is useful in this 
 connection : 
 
 “When planning the construction of a carbon-black plant, 
 information on the following points should be obtained; distance 
 from railroad or navigable stream, depth of wells, thickness of gas- 
 bearing strata, gas pressure, gasoline content and knowledge as to 
 whether gas is casing-head or dry, amount of proven territory, 
 history of field, drilling practice, location of field in regard to large 
 centres for domestic and industrial distribution of gas, distance 
 from large trunk pipe-lines for transportation of gas, open flow 
 capacity of gas wells on prospective leases, and a test on the richness 
 of gas for the approximate quantity of carbon black that one expects 
 to procure per thousand cubic feet.” 
 
 It is important to test natural gas for its carbon-black value 
 both by chemical analysis and by means of special test apparatus in 
 which a known quantity of the gas is burned and the carbon black 
 deposited on a metal plate, collected and weighed.”* 28 The varia- 
 tion in the amount of carbon black obtained from different qualities 
 of gas burned by the same process is given in Table VII, due to 
 D. B. Dow.? 
 
 It will be observed that the yield of carbon black from natural 
 gases follows very closely the ethane content, the heating value 
 of the gas and its content of elementary carbon calculated from the 
 hydrocarbons as determined by analysis. Methane (CH,) contains 
 33:5 lbs. of carbon per 1000 c. ft., as against a content for ethane 
 (C,H,) of 67 lbs. per 1000 c. ft., and the bearing of this is seen in 
 the yield of carbon black obtained in the case of Wyoming natural 
 gas. 
 
 Theory of Formation of Carbon Black. 
 
 The burning of natural gas in an incomplete supply of air results | 
 in the liberation of carbon, and the combustion, contends Bone,?4 
 
30 Blacks and Pitches ‘ 
 
 TABLE VII. 
 
 Carbon Content and Quantity of Carbon Black Recovered from 
 Natural Gas. 
 
 Louisiana. Virginia. Wyoming. 
 A. B. C. D. 
 MRL GHG «i sassis cele ean obs per cent. 94:12 70:75 | 65-23 46-45 
 PTOI. Gass bcescrasentane sce ri 3:44 24:14 | 30-07 43-10 
 Carbon dioxide ............ * 0-50 0:28 1-56 0:96 
 NWatnOROn ©) c12. Weg naecticnees 1-94 4-83 3°14 9-49 
 
 Net heating value in B.Th. U. ’ per 
 
 c. ft. at 0° C. and 760 mm. pres- 
 
 BOTS 5. < Cd saunas: cas Ow eense in lbs. 962 1,086 | 1,134 1,176 | 
 Carbon per 1000 ec. ft. of gas cal- 
 
 culated from carbon content of 
 
 methane and ethane .... in lbs. 33:8 39-9 42-3 44-3 
 Carbon black per 1000 c. ft. of gas 
 
 reported obtained ......... in lbs. 0-80 1-00 1-10 1-40 
 Percentage reCOVery — ..ccseseseceess 2-4 2°5 2-6 ol 
 
 takes place according to the following scheme as a result of hydroxyla- 
 tion : 
 
 B Sra via C 
 Oxidation H,:C:(OH), i 
 ‘ a ° e 
 CH yg (ACOH! 5 
 g 8 8 
 @|& Pac 2 | 
 OM Olan Oo | 7 
 ali al =| 7 
 & 8 8 
 AY ay A | 
 C + 2H, CO + 2H, co + H, 
 A’ B’ i 
 
 The tendency is always to pass from A to C. When the pro- 
 portion of methane to oxygen is that which is expressed by CH, + Og, 
 the reaction passes from A to BtoCtoC’. Iftheratiois 2CH, + O, 
 or higher even, then only a part of the methane can be oxidised 
 through the reaction A to C, and so part is decomposed at A by the 
 heat evolved in the A to C reaction. The minimum amount of 
 oxygen in which a methane flame will burn is 15-6%. Only in the 
 inner part of the flame, where oxygen supply is low but where the 
 heat is sufficient to decompose the methane, will carbon be evolved, 
 and the percentage of carbon to be obtained by the incomplete com- 
 bustion of methane is low; gases rich in ethane and its higher 
 homologues give higher yields of carbon. Bone noted that the 
 decomposition of methane, in the explosive combustion of hydro- 
 carbons, was a surface effect leading to a hard, gritty carbon, whilst 
 

 

 
 Fia. 6.—Channel Plant in course of Construction. 
 
Carbon Black at 
 
 the decomposition of ethane, ethylene, etc., took place throughout 
 the whole mass of the gas and yielded a soft carbon. The decom- 
 position of methane and the influence of different surfaces on this 
 have been discussed by W. E. Slater.?5 
 
 The function of the cold metallic surface, which is a feature 
 of all the commercial processes for making carbon black, is to cool 
 the liberated carbon in the flame sufficiently to prevent its com- 
 bustion, but obviously an optimum temperature is necessary. 
 Too cold a surface may prevent the maximum separation of carbon— 
 too hot a surface will cause too much carbon to be burnt and may 
 even change the physical characters of the carbon remaining. In 
 this connection a carefully regulated air supply is possibly the chief 
 desideratum, whilst the best temperature is about 500° C. 
 
 Commercial Methods of M anufacture. 
 
 The principal methods in commercial practice in U.S.A. are the 
 following, arranged according to the quantity of black produced : 
 
 1. Channel process. 
 
 2. Small rotating disc process invented by A. R. Blood in 
 1888 and now extensively used. 
 
 3. The large plate process invented by G. L. Cabot. 
 
 4, The roller process invented by E. R. Blood. 
 
 5. Thermal decomposition or cracking. (This is still largely 
 in the experimental stage.) 
 
 The Channel Process.—Briefly this is operated as follows, accord- 
 ing to R. O. Neal, who has described the process in detail in the 
 Bulletin.” | 
 
 The natural gas from the wells, after suitable pressure regulation, 
 passes through gasometers, which regulate the flow of gas, and pass 
 it on to burners arranged in the condensing buildings. It is essential 
 that equal gas distribution be obtained in each building. The con- 
 densing buildings are of sheet iron, about 700 ft. long and 8 to 10 ft. 
 in width, arranged in rows along both sides of an alley, through the 
 centre of which alley and placed at right angles to the condenser 
 units is the main driving shaft operating the machinery within the 
 units. 
 
 In the interior of the buildings are trestles or tables about 6 ft. 
 wide and about 6 ft. high, and on each trestle are usually placed 
 8 rows of channels, these latter being hung from trucks that run on 
 overhead rails. The channels have a reciprocating motion of 4 to 
 5 ft. \ 
 
‘yoelgq woqieg Surkoauo0g jo poyyop—'), “AL 
 
 
 
 20d ub. C) 
 
 eee NE Oe ee ee 
 
 “E-BUI7 UNGL9 
 
 
 
 
 
 L208. AS 
 : Ze 
 imma) 
 
 Ox-2) 
 f ims) 
 
 a 
 err e@ ~ or re en ee eae aaa Ee 
 " 
 
 Sy Wiggs eset eee eae c eee oon == 
 
 32 
 
Carbon Black 33 
 
 In Fig. 6 (A and B), taken from Bulletin 192 of the Bureau of 
 Mines, U.S. Department of the Interior, Washington, and reproduced 
 here by the courtesy of that Department, particulars of a channel 
 plant in course of construction are shown. 
 
 The gas is burned through lava tip burners, there being usually 
 1600 of such in a building of the size described here. An even, 
 luminous, smoky flame results, the draught being suitably regulated, 
 and the carbon black is deposited on the underside of each channel. 
 Underneath the channels are arranged the carbon-collecting hoppers, 
 spaced about 4 ft. apart, and these catch the carbon removed by 
 scrapers set in the hoppers; different types of scrapers with different 
 methods of actuating them are in use, but one type in use is that 
 shown in Fig. 7, reproduced from Bulletin 192. 
 
 The carbon black is conveyed by spiral conveyors to a room 
 containing bolting machines; these are galvanised sheet-iron drums 
 having across one end a screen of 45- to 60-mesh iron, over which 
 fibre brushes rotate in order to remove grit and scale from the black. 
 From the bolters, the black is conveyed to a storage bin, and packed 
 in 123 lb, sacks, or in 150 lb. ones if for export. 
 
 Plants are usually built in 60 barrel units (50 lbs. black per barrel), 
 and there are generally 18 buildings to an installation. A 20—25h.p. 
 internal combustion gas or expansion engine is quite sufficient to 
 actuate the channels and other moving parts of an installation. 
 
 A detailed plan of a carbon-black plant is shown in Fig. 8, repro- 
 duced from the Bulletin. 
 
 Small Rotating Disc Process.—In this process, invented by A. R. 
 Blood ** in 1888, and now in extensive use, the gas is burned at 
 lava tips set to the number of 18 to 24 in the upper side of a ring 
 of about 28 ins. diameter. The carbon black is deposited on cast- 
 iron discs as shown in Fig. 9, reproduced from the Bulletin. 
 
 The discs are 36—42 ins. in diameter, and together with the driving 
 gear and pinion resemble flat umbrellas. The hopper and the 
 scraper radiate from the shaft and, like the burners, are stationary. 
 The discs are arranged in rows of 21 each, with 4 rows to the 
 condensing building, and an independent driving shaft for each 
 row of discs. One unit plant has usually 16 to 20 buildings. 
 
 In all other respects the methods detailed in the channel process 
 are followed. : 
 
 The Plate Process.—This was invented by G. L. Cabot 2? about 
 1892, and the details of the process are shown in Fig. 10, reproduced 
 from the Bulletin. 
 
 The plates on which the carbon black is deposited are 24 ft. in 
 
 3 
 
34 Blacks and Pitches 
 
 diameter, and made up of 48 segments, supported by a control 
 mast and cables. These plates are stationary, though the burners 
 and the scrapers rotate, making one revolution every 8 minutes. 
 Usually 1265 lava tips are in use to each plate; the plates are 
 surrounded by a circular building 26 ft. in diameter, constructed of 
 sheet iron. The other arrangements for.conveying bolting and 
 packing are just as described for the channel process. Fig. 10, 
 
 
 
 
 
 “ 
 io nS ee, 
 
 
 
 
 
 
 a = 
 (es am 
 
 , ‘eS 
 ty ool es 
 ¢. ; 
 
 cee 
 ws ht oyaehye 40g 
 
 ez 
 
 
 
 SRNL PTS Tee 
 hi S 8 
 ie fo 
 i aaa 
 
 ‘ae a ae 
 a se , 
 
 ES a 
 — 
 Reo 
 an eee een 
 3 
 t 
 t 
 
 | 
 > 
 
 eae Fe ae 
 
 Enero mem mer 24". G2. - 
 
 Fig. 8.—Carbon Black Plant in detailed Plan. 
 
 reproduced from the Bulletin, gives a good idea of the appearance 
 of the plate system in actual operation. 
 
 The Roller or Rotating Cylinder Process.—This process, due to 
 KE. R. Blood,?§ and later improved, produces the highest-priced grade 
 of carbon black. The gas is burned through lava tips having a 
 round perforation, instead of the usual fish tail, and a cylindrical 
 flame is produced. The rollers on which the carbon black is deposited 
 are 3 to 8 ft. in length and 8 ins. in diameter, and they make one 
 
 complete revolution in 30 minutes. The scrapers are set on top of - £ 
 
 the rollers and are continuously in operation, and 6 to 9 rollers are 
 enclosed within one hood, and below the cylinders is a trough- 
 shaped hopper to collect the black. 
 
 A typical building has 196 to 288 rollers, 10,000 lava tips and 
 
 \ 
 \ ‘ 
 

 
 Fia. 9.—Depositing Surface for Carbon in the Rotating-Disc Process. 
 
 
 
 
 DETAIL OF COLLECTING BOX. 
 Allached on underside of 
 
 (/ 
 
 G 
 
 DEPAUL SUPPORTING MAST AND DRIVING MECHANISM 
 
 Fia. 10.—Details of the Plate or Cabot Process. 
 

 
 
 
 my 
 
Carbon Black 35 
 
 about 24 to 32 hoods, and a like number of hoppers. The buildings 
 are usually 65 to 100 ft. long and 25 to 35 ft. in width. 
 
 Fig. 11, reproduced from the Bulletin, shows the details of this 
 system. 
 
 Various factors, such as the design of the plant, weather con- 
 ditions, gas pressure and the presence of salt water or oil in the gas, 
 affect the yield of carbon black obtained in the commercial methods 
 of manufacture outlined. Nothing apparently is to be gained by 
 the artificial cooling, using air or water, of the cooling or depositing 
 surfaces of carbon-black plants. 
 
 For a discussion of the economics of the industry the reader 
 is referred to the Bulletin and to papers mentioned in the bibliography 
 at the end of this chapter. 
 
 Other Methods of making Carbon Black. 
 
 Carbon black was first manufactured from artificial gas, and, as 
 R. Irvine *® pointed out many years ago, was made in this country 
 long before American natural gas was so used. 
 
 The same quality of black was made with similar but smaller 
 apparatus, ordinary town gas being used as far back as 1860. To 
 produce 1 lb. of black required 1000 c. ft. of gas, and the cost was 
 5s. per lb. of black obtained. Irvine ?® suggested that gas from the 
 Scottish shale retorts might be used. 
 
 One firm in this country is manufacturing carbon black from 
 coke-oven gas, but beyond the fact that black is generally equal in 
 quality to the American carbon black, no information is available. 
 It would be interesting to know the yield of black from 1000 c. ft. 
 of this gas, in view of the fact that in the case of natural gas the yield 
 of black bears a close relationship to the ethane content of this 
 gas. P. Lebeau and A. Damiens *° have given the composition of a 
 number of samples of coke-oven gas, the ethane content being 
 only 0-45 to 1:64%, which is very much lower than the recorded 
 figure for any natural gas, and it seems legitimate to infer therefore 
 that the yield of carbon black from coke-oven gas is much inferior 
 to that from any natural gas. 
 
 Acetylene black has been made by exploding mixtures of acetylene 
 and air under pressure, the acetylene being made from the 
 refuse of calcium carbide factories. Patents 34 32 33,34 have been 
 effected from time to time describing the manufacture of acetylene 
 black, and according to G. L. Cabot *> acetylene gas possesses the 
 quality of exploding by itself, without admixture, and black has 
 been made by exploding this gas under 5 atmospheres pressure, 
 either by compression or by electric spark. , In those cases where 
 
 4 
 
erat 
 
 “MadOI96 
 
 
 
 491I{C4 
 
 
 
 ‘ . 
 APOUS 1QL 
 
 ‘meyshg sepuyéD Suryeqzoy JO J9TJOY CYT— TT “OT 
 
 Y-VW HUOIZ3BaS 
 
 #2/U] $00 
 
 JOB sdjjoy 
 ~ feo Rs 
 
 Rene ae 32 gZ 
 > 4 F/ 
 
 MAIC 425 3" 
 
 
 
 36 
 
Carbon Black 5 | 
 
 explosion occurs in the presence of air, it has been shown that the 
 acetylene not only is oxidised, but is actually dissociated. The 
 black obtained is inferior in colour and strength to the carbon 
 black from natural gas, but is useful where its bluish tinge gives 
 it a preference in certain industries. The supply is, however, 
 uncertain, and is chiefly confined to the continent of Europe. 
 
 The yield, in the case of a small Chicago plant burning acetylene, 
 as in the manufacture of carbon black from natural gas, is 11-6 lbs. 
 of black per 1000 c. ft. of acetylene—a recovery of 17:3%. 
 
 Numerous other methods have been patented for producing a 
 high yield of carbon from natural gas or other hydrocarbons, the 
 gas being generally split up into carbon and hydrogen in a retort 
 -at high temperature in contact with refractory material. Mention 
 may be made in this connection of the work of R. H. Brownlee and 
 R. H. Uhlinger,®® of Szarvasy,?’ of McCourt and Ellis,3* of W. G. 
 Laird,®® and of a recent attempt of J. A. McGuire,*® who causes 
 chlorine to react with an excess of hydrocarbon. No great quan- 
 tities of usable carbon black have been made by any of these processes. 
 
 Properties of Carbon Blacks. 
 
 All the earbon blacks are very intense in colour, glossy, whether 
 rubbed dry or in varnish, and have an extraordinary mixing strength. 
 They mix with water by simply shaking them with it, though lamp- 
 black usually will not, and this is a convenient method of distinction. 
 
 Carbon blacks generally are hygroscopic, and some blacks will 
 absorb as much as 15% of moisture. Carbon black contains con- 
 siderable quantities of carbon monoxide, carbon dioxide and oxygen, 
 the latter probably being present in some sort of loose combination as 
 ** fixed oxygen,” and the carbon dioxide may be present to an extent 
 equal to 1% of the weight of moisture present. 
 
 The specific gravity of carbon black varies from 1-8 to 2-1, and 
 its determination requires some little care in order to eliminate the 
 air bubbles always enclosed in the pigment. The determination 
 may be carried out in the usual type of specific gravity bottle, which 
 is weighed empty, full of distilled water and then full of the dry 
 pigment. The bottle containing the pigment is then filled with 
 distilled water and the enclosed air bubbles are removed by heating 
 and until the pigment is thoroughly wetted. The bottle and con- 
 tents are then brought to a temperature of 15-5° C., and additional 
 water is added if necessary, until the bottle is quite full, and then 
 weighed again. The ratio of the weight of the pigment to the weight 
 of water displaced by it gives the true specific gravity of the pigment. 
 
38 Blacks and Pitches 
 
 When making this determination for lampblack, it is preferable 
 to use benzol or some liquid which will completely wet the pigment. 
 Gardner *1 has drawn attention to the difficulties to be encountered 
 in determining the specific gravity of fine pigments and indicated 
 how these difficulties may be overcome. 
 
 The present writer ** has examined a number of genuine carbon 
 blacks, with the results recorded below : 
 
 Tasie VIII. 
 Analyses of Carbon Blacks. 
 
 
 
 ~The acetone extract of the above blacks was a mere trace—too 
 small to record in the data. 
 
 The volatile impurities in carbon black may be removed, accord- 
 ing to J. C. Morrell,*® by heating the black to pie NE es C. in an 
 iron crucible under suitable conditions. 
 
 In Table IX. are details of some very sontnles analyses of carbon 
 blacks due to W. A. Selvig. 
 
 The determination of volatile matter is carried out in the same 
 way as outlined in any of the well-known volumes dealing with the 
 analysis of fuel, and need not be detailed here. The U.S. Bureau of 
 Mines recommends for the determination of moisture, ash, and ace- 
 tone extract the following standard methods, full details of which 
 will be found elsewhere, due to F. M. Stanton and A. C. Fieldner.** 
 
 Moisture—‘‘ A one-gram sample of the black is placed in a 
 weighed porcelain crucible, and heated for 1 hour at 105°C. in 
 a constant temperature oven in circulating dry air. The crucible 
 is then removed from the oven, covered, and cooled in a desiccator 
 over sulphuric acid. The lossi in weight multiplied by 100 is recorded 
 as the percentage of moisture.”’ 
 
 Ash.—* The crucible containing the residue from the moisture 
 determination is heated gradually with a Meker burner, or better 
 in a muffle furnace, to about 750°C. or to a cherry-red. Ignition 
 is continued until all the particles of carbon have disappeared. The 
 
crucible is then cooled in a desiccator and weighed, after which it is 
 heated again for 15 minutes, cooled in a desiccator, and re-weighed. 
 If the change in weight is more than 0-0002 gram, the process is 
 repeated, until successive weighings are constant to this figure. 
 The weight of the crucible and ash minus the weight of the crucible 
 
 Carbon Black 
 
 is taken as the weight of the ash.”’ 
 
 | | Tasre IX. : 
 Analyses of Carbon Blacks, Lampblacks and other Blacks (Selvig). 
 
 Calarific value. 
 
 Method of manufacture. 
 
 Manufacturer. 
 
 Brand 
 
 ; ys 2 lt le, ee : 
 Pp ash be Pe 
 "ecs- ey 8B : ; 
 
 AA EEE 
 Bes Esae pear oie soa 
 43 4> $53 5835 q 4 
 a. Gs EES ESE: a ot 8 i 
 Uige gga geos ye Gong seen a 
 Seeecl tagess 2 ba : 
 AZaPIo40, sacs Bie E ‘ 
 oS Goce ofae 3 : 
 geyhedeg2 i222 03 2 A: 
 Raa Soon msm : bb : 
 peat crcune 
 ik eee sae 
 5 va: : 3 i 
 See eeeghede | 
 A i ee ee 
 ; Foe ; ; 2B 4 & 
 822849929 G8 
 3 24183. 5 2 am 
 
 g a § :2 gq a a fig 
 Boi, 222° 4 88 
 6 “xed pea g 8 8 Sxl 28 
 a =P Pues y 5 28s 
 on ez tM Saas 2 
 
 Bae ees 6S eR. ole as ie 
 
 44 
 78 
 88 
 
 1.85 
 ‘L8 
 “180 
 iv ai 
 La 
 
 EN et et et a cmt eh ped md med ed A el ad ed ed el odd eed ed, 
 
 BEEP SS SC2SEESSRERSgSS 
 
 Cee 66S Od a ew ah 8 
 
 SESSSSSSSSSSSELSSSSSSB 
 So 
 
 SARESISLSSRERERTATTLL 
 
 addsasies 
 
 HRSSBSSSALSSSSSSSSSSSs 
 
 are ie BREA nl ew vee ig Ge @ € Sw 6 8a 10 
 
 SSASSSegs 
 eee Sei Tee arn one Sd Saath ayia Se 
 
 ESASISSRR5RE8 
 
 Sir besisidadar é 
 = pce 
 
 ‘A 
 
 bon black. 
 
 € ee H Ore) @ 
 
 oeeees 
 ie fe © 
 a AC es 
 ee eT 
 
 ©) oP gee e 
 0 ks iy 
 2 eo Teta ence 
 ee dee or 
 
 ee a TET RS ea a Sea Si SP er rh ae ES 
 
 Pe Poe Sk BW er ae ep kl eee Mee a ce et Tee te ie 
 
 BEEBSa5SBR 
 
 et et et et 
 Whe ae ee © he eee © ® 6 °0F fk Re ae ee 
 
 REDISSSSSALLLR FERSNTSSIRaS 
 SESSSSRASSSKES MKSgde rye sssa 
 
 Be igs: 
 
 g ida ies : 
 
 ARIABLISLERSAR SLKRRSRSZTRB 
 didsssedddgdas Sidsdesgdsdss 
 
 SS 
 
 
 
 3 
 Poig. : i mas§ 
 ei gai i £adg 
 
 i Be t ( t RERS 
 an ee 
 ag: 9s: : g83e 
 BOS Spy: 3 slug : 
 aef 24: i deg : 
 258 ee 3 Be2g : 
 RJ) g&: : Bhp : 
 ap 8 i: ita : i 
 25 ee soe 
 : : Es fig ba 
 
 Pen ts a . 
 be ait isl 7 y 
 
 fedfa i bass 
 eSB LTR Rhee 8 
 8 8 & yee 
 ga: itr i ig a 
 Te de ee RE ie ae 
 
 es dhe) 3 4 4 
 eaPagus 6 “Bs A £4.55 
 UnGn Oy ag a i-} 
 Sacuag Ug a gf 
 Gas 4 a 5 & & 
 
 
 
 and ash free. 
 
 @ The form of analysis is denoted by number as follows: 1=sample as received; 2=dried at a temperature of 105° C.; 3=moisture 
 
 Acetone Extract—‘ A two-gram sample is weighed into an 
 
 alundum or paper extraction thimble of 20 c.c. capacity and the 
 extraction carried out for 1 hour, using any standard apparatus of 
 The weight of the residue after evaporation 
 
 the Soxhlet type. . 
 The extract for a 
 
 of the acetone is taken as the acetone extract. 
 
 pure carbon black is usually zero.” 
 
40 Blacks and Pitches 
 
 The estimated distribution of carbon black per annum produced 
 in the United States is : 
 
 Lbs. 
 Rubber industry : ’ ; . 20,000,000 
 Printer’s ink ; : : : : 10,000,000 
 Export ; ‘ 8,000,000 
 Stove polish ; : 4,000,000 
 Phonograph records. ; 500,000 
 Other Uses. % : ; : : 1,000,000 
 
 Under other uses are paint, carbon paper, type ribbon, tarpaulins, 
 carriage cloth, black leather, paper, bookbinder’s board, shoe polish, 
 electric composition insulators, celluloid, buttons, etc. Considerable 
 quantities are shipped to England, France, Japan and China. 
 During pre-war times one-third of the annual production was 
 exported. 
 
 Generally speaking, it may be said that carbon black is preferable 
 for black printing ink, stove polish and vulcanised rubber, lamp- 
 black being the better pigment, according to G. L. Cabot, for colour- 
 ing oilcloth, leather and rubber, other than vulcanised, and generally 
 for paint, although carbon black is preferable for certain kinds of 
 paint and varnish. For further information, the reader may be 
 referred to a paper by Perrott and Thiessen.*® 
 
 REFERENCES. 
 
 19 J, Soc. Chem. Ind., 1894, 18, 128. ?° IT: 16 U.S. Dept. of the Interior, 
 U.S. Geological Survey, 1921, p. 145. 21 Monthly Report of Investigations, 
 Bureau of Mines, U.S. Dept. of the Interior, March 1920. 72 “‘ The Sampling 
 and Examination of Mine Gases and Natural Gas,’’ G. A. Burrell and F. M. 
 Seibert, Bulletin 42, U.S. Bureau of Mines, 1913. * ‘“‘ Testing Natural Gas 
 for Carbon Black,’’ Chem. and Met. Hng., 1920, Feb. 25th. ?4 W. A. Bone, 
 Phil. Trans. Royal Soc., 1915, 215, 275. 5 J. Chem. Soc., 1916, 109, 160. 
 26 U.S. Patent 387,487 of 1888. 27 U.S. Patent 468,510 of 1892. 28 U.S. 
 Patent 269,378 of 1882. 9 J. Soc. Chem. Ind., 1894, 18, 130. °° Compt. 
 rend., 1920, 171, 1385. °1 Morehead, U.S. Patents 779,728 and 986,489. 
 82 Pictet, English Patent 24,256 of 1910. °% Wegelin, German Patent 
 201,262 of 1907. %4 Bosch, German Patent 270,199 of 1913. °° ** Lamp- 
 black and Carbon Black,” 8th International Congress of Applied Chemistry, 
 1912, 12, 13. °° U.S. Patents 1,168,931, 1,265,043, and 1,478,730. %* U.S. 
 Patent 1,199,220. °8 U.S. Patent 1,276,385. %®® U.S. Patent 1,490,469. 
 40 U.S. Patent 1,498,924. 41 “‘ Fineness and Bulk of Pigments,’ H. A. 
 Gardner, Circular 148, U.S. Paint Manufacturers’ Association, 1922. 4%. Un- 
 published results. 43 U.S. Patent, 1,359,091 of 1920. 44 F. M. Stanton 
 and A. C. Fieldner, ‘“‘ Methods of Analysing Coal and Coke,”’ Tech. Paper 8, 
 U.S. Bureau of Mines, 1913. 4° ‘‘ Carbon Black: Its Properties and Uses,” 
 J. Ind. Hing. Chem., April, 1920. 
 
 al 
 
 Bibliography—Carbon Black. 
 
 “* Efficiency of Carbon Black Plants,’’ Chemical and Metallurgical Engineer- 
 ing, New York, July 5th, 1922. ‘‘ Startling Waste of Gas in Carbon Plants 
 is Shown in Report,’’ American Gas Journal, New York, May 27th, 1922. 
 ** Carbon Black Industry in Louisiana,’’ Chemical Age, New York, December, 
 
Carbon Black 4] 
 
 1920. ‘‘Carbon Black Industry,” Manufacturers’ Record, Baltimore, Md., 
 February 24th, 1921. ‘‘ New Idea in Carbon,” Petroleum Age, Chicago, 
 Illinois, January, 1921 (relates to use of electrical precipitation process). 
 “Carbon Residue from Oil-gas Manufacture used for every Purpose for 
 which Coal is Utilised,” American Gas Journal, January 20th, 1917. 
 *“Channel Process for making Carbon Black,’’ Chemical and Metallurgical 
 Engineering, October 13th, 1920. ‘‘ Disk, Plate and Cylinder Processes for the 
 Production of Carbon Black,”’ zbid., October 20th, 1920. ‘‘ Louisiana Natural 
 Gas and Carbon Black Manufactures,’’ Chemical Age, September, 1921 
 *“Demand for Carbon Black,” Gas Age, April 10th, 1920. ‘‘ Carbon Black, 
 a Natural Gas Product,” Scientific American, January 1920. ‘‘ The Carbon 
 Black Industry,’’ Chamber of Commerce Journal, May 16th, 1924. J.B. Garner, 
 ““The Chemical Possibilities of Carbon Black,” Proc. Nat. Gas Assocn. of 
 America, 1918,10, 136. ‘‘ Thermatomic Carbon Black,’’ Chem. Trade Journal, 
 1924, 75, 712. ‘‘ Chemistry and Physics of Carbon Black,’ G. L. Cabot, 
 Paint, Oil and Chem. Rev., 1924, 78, No. 21. ‘‘Manufacture of Gas Black,”’ 
 E. H. Thomas, U.S. Patent 1,514,638 of 1924. A. Bonnington, U.S. Patent 
 1,515,333 of 1924. 
 
CHAPTER V 
 LAMPBLACK 
 Methods of Production—Properties, Uses and Analyses. 
 
 LAMPBLACK is the soot or impalpable powder obtained from the smoke 
 arising during the incomplete combustion of various carbonaceous 
 substances such as vegetable and animal oils, pinewood and resinous 
 materials. Soot has from time immemorial been used in painting 
 and colouring a variety of objects, and it was the basis of the earliest 
 known inks. The Chinese were probably the first to make it on an 
 extensive scale for the manufacture of Chinese inks as known to 
 the ancients. The method of manufacture was very primitive— 
 and still is in China—the pigment being made by igniting resinous 
 material in a pot in a closed room and leaving the material to burn 
 itself out through lack of proper air supply. 
 
 Neither the yield nor the quality of the black could be considered 
 satisfactory when produced in this way, and ordinary soot from the 
 chimney back, once in common use as a pigment, is now discarded as 
 being too impure owing to the amount of gritty and empyreumatic 
 matter it contains, together with other impurities, and by reason of 
 inferior colouring power. 
 
 The German method at one time was to burn resinous woods in a 
 closed furnace and collect on woollen cloths, exposed to the smoke 
 emitted, the resulting black. 
 
 In modern methods of manufacture the starting point is the 
 dead oil of coal-tar works, an oil containing a large amount of - 
 naphthalene, some phenol and various aromatic hydrocarbons, 
 particularly suited to the manufacture of lampblack by reason of the 
 large percentage of carbon contained therein. These compounds, 
 burnt in an insufficient supply of air, yield from 15 to 35% of their 
 weight in the form of lampblack by deposition in suitably arranged 
 chambers. 
 
 According to Cabot,®> the quality of the black is determined by 
 the size and shape of the furnaces in which the oil is burned, by 
 the heat to which it is subjected during the progress of the manu- 
 facturing operation, by the position in which the black is deposited, 
 and by the care exercised in selection of the raw materials employed. 
 
 The oil is normally allowed to flow in a sluggish stream into an 
 earthenware or iron pot or pan, in which burning occurs, and from ~ 
 which the smoke passes through flues into the chambers in which 
 the black is deposited. 
 
 The best grades of black, generally speaking, are obtained in 
 furnaces of moderate size so built that the black is practically 
 
 42 , 
 
Lampblack An 
 
 calcined at the time it is deposited and carries down with it but 
 little empyreumatic matter. The products of combustion are 
 usually carried through a series of chambers, in which are partition 
 walls, and the gases charged with lampblack are thus compelled to 
 follow a tortuous path. The baffling effect of the partitions not only 
 facilitates the deposition of the black, but may increase the per- 
 centage of deposition, though, of course, the placing of partitions can 
 be overdone, and then the speed at which the gaseous products are 
 impelled through the chambers becomes too great, leading to loss of 
 black. 
 
 ~ 
 
 VLA dL Lb hhh hh Lb b hf pitdddldlde,  plddebdbeke. 
 3a g 
 ~ 
 
 CSS 
 
 NNN 
 
 SY 
 SS 
 
 BS 
 
 SSS 
 SSS) 
 SEES 
 ASE ASRRRA NAS ERNRRRARRRANS, 
 AAAAASARRRRRAARARRAESSARRRRRRS 
 
 \ 
 
 Z “or y 
 
 N 
 
 Ns 
 
 A. Elevation. 
 
 ULLLLLLILIILA MM MY f bhtddt tty 
 
 
 
 Fie. 12.—Arrangement of a Lampblack Plant. 
 
 The charging of lampblack furnaces must be performed quickly, 
 to minimise the possibility of entry of large volumes of air into the 
 furnaces and chambers owing to the risk of formation of explosive 
 mixtures of air and the unconsumed combustible gases in the 
 chambers or collectors, as they are also termed. The furnaces are 
 kept at work for several days and then the chambers are allowed to 
 cool gradually, care being necessary to admit the air only at a rate 
 sufficient to remove any combustible gases from the chambers. 
 Lampblack is very strongly pyrophoric, and therefore the greatest 
 care is necessary in cooling it, for until it is cool it cannot be removed 
 from the chambers. 
 
 The accompanying sketches (Fig. 12) indicate, in plan and 
 elevation, the type of arrangement of a lampblack plant for securing 
 
4.4. Blacks and Pitches 
 
 efficient deposition of the black. From time to time mechanical 
 devices have been used in the form of stirrers to churn the air and 
 cause the condensation of the smoke in masses sufficiently large for 
 it to deposit itself. 
 
 Resin, resinous woods, tar and pitches are still to a small extent 
 used in the manufacture of lampblack, though the product is said not 
 to be so good as that from the dead oil of tar. The manufacture 
 from hull bran has been described by Hershmann,*® from peat by 
 J. E. Smith,4? and from coal-tar pitch by A. C. Evans and others.*® 
 By the incomplete combustion of oil,*® the burning of oil fuel,°° and 
 in several other ways based on the use of coal tar,>) 5? lampblack 
 may be obtained. 
 
 Properties of Lampblack. 
 
 Usually this contains about 80% of amorphous carbon, the rest 
 being traces of resinous oils, empyreumatic matter, moisture, traces 
 of adsorbed carbon dioxide and carbon monoxide and grit from the 
 floors and walls of the collecting chambers. In contrast to carbon 
 black, it has a grey hue. Its true specific gravity is 1-7 to 1:8 
 usually, and though it mixes well with oil and varnish, it does not 
 generally mix with water. 
 
 The contrasting properties and qualities of lampblack and carbon 
 black have been described by G. L. Cabot,1* 35 and from microscopic 
 appearance it seems likely that in their structure.these two black 
 pigments differ from one another. As an explanation of this, 
 Perrott ? has put forward the suggestion that the difference may be 
 due partly to the fact that as lampblack is made from a complex 
 mixture of carbon compounds, each with its own optimum tem- 
 perature of decomposition, a uniform product is less likely than 
 might be expected in the case of carbon black produced from such a 
 relatively simple raw material as natural gas. 
 
 The very best qualities of lampblack, known technically as 
 vegetable black, are finer and softer in texture than ordinary lamp- 
 black, this vegetable black being the black deposited farthest away 
 from the burning raw material. Such vegetable black is blacker 
 than the commoner grade of lampblack, and is lower in ash and oily 
 and empyreumatic matters. The term “ vegetable black” is due 
 to the circumstance that at one time the finer seed oils were used to 
 produce this pigment. Tables X and XI (reprinted from Tables 
 XIV and XV of Bulletin, 192) record the analyses of some lamp- 
 blacks, particulars for other black pigments being given for 
 contrast. 
 
Lampblack 
 
 TABLE X, 
 
 Analyses of Carbon Blacks. 
 
 
 
 Lon Lon ang Short Short Short 
 blac blac blac black black black 
 No. 1. No. 2. No. 3. No. 1. No. 2. No. 3. 
 
 en 
 
 
 
 
 
 nS ON Se re ea eee 3. 56 713 30 2.25 3. 02 3.12 
 Wiolative MIALtGF. 5 oo uc nee aswescdcecc 11. 99 13, 41 10. 49 5. 60 5. 48 5. 58 
 RMEMRE Pee eras otra oa. sratars aise geaw'y 84. 40 79. 44 84. 16 92.13 91, 47 91. 22 
 Pe a cereh ne rkewnavecs chs aswecavat tine +05 02 14 02 03 . 08 
 ULTIMATE ANALYSIS (AS RECEIVED). 
 CNC eet se a 1.19 1, 32 1.11 74 . 88 1.05 
 tie Se ne oa aie 88. 17 84. 56 &7. 98 94. 78 93. 50 93. 63 
 IO OES NE Sa aa 04 . 04 08 . 00 04 .05 
 I ER Ae LE pica Sinn ciceb e's oe wae 10, 54 14. 00 10, 68 4. 37 & 25 5.19 
 PERMA 2 oar Pg eink baw clceh wattas one cedSe > 01 . 06 Ol 00 30 00 
 OL A CeO eae a See - 02 -14 02 03 - 08 
 ULTIMATE ANALYSIS (MOISTURE FREE). 
 MMO eE ae con wn tcrrcye a oees 82 57 «55 50 52 72 
 Te oh TopRank ee 91. 42 91. 05 92, 91 O56, 86 96, 41 06, 64 
 LE VEE NEE ee eee See 04 07) - 08 . 08 04 - 05 
 ea is BEE 2 EER ee 7. 68 8, 28 6, 36 2. 43 2, 68 2. 51 
 LS eee a a ee eee - 01 . 06 91 . 00 -3l . 00 
 eee ON nas R ci SaaS USL ia select gra wna 05 . 02 -15 02 . 08 , 08 
 True specific gravity. .............-...00-- 80 1, 78 1, 88 1,85 1. 80 1,78 
 TABLE XI. 
 
 Analyses of Lampblacks and other Blacks. 
 
 
 
 
 
 
 
 
 
 
 Carbon from 
 
 
 
 
 
 
 
 
 
 
 
 
 
 ! f 
 Lampblaeck. Willow! W baer - 
 Bone | Vine . 
 black. | black. | CBS! | ,pul 
 : *! coal. | black. 
 
 
 
 
 No. 1. | No. 2. 
 
 
 
 
 
 PROXIMATE ANALYSIS. 
 
 
 
 IS a a a a 3. 88 
 Wr OUBPIe MIAELET. oo 5 a as orcs weceeae 10. 92 
 Pimed Carbon ie. ..5 cose es ewks ceva 2. 68 
 
 OL Re ane 82. $2 
 
 
 
 LU, Eee go ee a oe ebz 13 - 83 
 Geren Aon win Sew ieierac cea 87. 62 87, 84 & 64 
 eM ete hea oe liciasncwia eaeee e's cay ie a - 00 1, 06 
 ON geo ang Liye Sam ld ssc ove 1.18 9. 95 6. 8A 
 MERI EE a ee he anche dee caccese oT 64 08 
 RRNA fe esi Son's a minivieis: dae . 00 -06 | 82.52 
 
 
 
 
 RE MOPN oe Oe. So Sc in now pils dcd'ateie x 1, 20 47 
 NS Oe ES are eae ee 98, 00 90. 67 8. 99 
 MOREE GEP Ta phaseio iS aia's ys visti wis piace aren =k vie od . 60 1.10 
 UGE es Ses 84 7.41 3.53 
 ER hienciids uy peewee pnnsincecse 57 66 . 06 
 Ie 5 ee oe = a . 00 06 | 85.85 
 (ACETONE OXtVACt........sicsacevescnssee - 
 
 
 
 45 
 
46 Blacks and Pitches 
 
 REFERENCES. 
 
 46 U.S. Patent 1,188,936. 47 U.S. Patent, 916,049. 4% U.S. Patent 
 1,175,732, of 1916. 4% Lampblack, Ltd., English Patent 17,223 of 1912. 
 50 Franz Maiser, German Patents 203,711 of 1909 and 288,990 of 1914. 
 51 Riitgerswerke A.-G., German Patents 208,600 of 1908 and 383,922 of 1922. 
 52 French Patent 480,487 of 1916. 
 
 Bibliography—Lampblack. 
 ‘“‘Colour Manufacture,” Zerr, Riibencamp and Mayer, Charles Griffin 
 & Co., 1908. T. W. 8. Hutchins, Manufacture of Lampblack, U.S. Patent 
 1,309,070 of 1919. W. H. Frost, U.S. Patent 1,438,032 of 1922. J. G. 
 Bearn, ‘**'The Chemistry of Paints, Pigments and Varnishes,” Chapter XII, 
 Ernest Benn, Limited, London, 1923. 
 
CHAPTER VI 
 BLACK PIGMENTS IN PAINT MANUFACTURE 
 
 Consideration of the Physical Properties Involved—vVarious Uses of Black 
 Pigment Paints—British Standard Specification for Carbon Black. 
 
 BLACK pigments find extensive use in various branches of the paint 
 industry, and reference has already been made in earlier chapters 
 to the use of metallic black pigments and particularly of graphite 
 in this connection. The evaluation of black pigments according 
 to their physical properties is of prime importance when considering 
 the suitability of these pigments in the manufacture of paints, and 
 the chief physical properties we must look at are as follows :— 
 
 1. Specific gravity. 
 . Fineness. 
 . Oil absorption. 
 . Tinting strength. 
 . Colour. 
 
 Chemical properties have been discussed in the earlier chapters 
 and need not be touched upon again here. Such physical charac- ~ 
 teristics as covering power, hiding power, opacity, apply to pig- 
 ments only when viewed in conjunction with paint media, and 
 their study therefore does not really concern us here. 
 
 1. Specific Gravity—The method of estimating this has been 
 outlined in Chapter III, and for a pigment in a fine state of division 
 is not quite as simple an operation as may be imagined. The sources 
 of error lie in the difficulty of entirely removing entangled air 
 and the difficulty of ensuring that the finest portions of the pigment 
 are completely “ wetted,’ and it is therefore important that a 
 proper vehicle should be selected in which to determine the specific 
 gravity. In this connection the reader is referred to a paper by 
 Nuttall *? on the “ wetting power ” of a liquid. 
 
 Increasing attention has been paid in recent years to the specific 
 gravity of pigments, owing to the bearing this has on the volume 
 of mixed paints, and also on the behaviour of pigments when sus- 
 pended in liquid media. In some measure also there is a connection 
 between the specific gravity of a pigment and the amount of oil 
 required to grind the pigment into a uniform stiff paste, but this 
 characteristic is more properly correlated with fineness.? 
 
 Cu Bm OG bo 
 
 Average Specific Gravity of Black Pigments with others for Comparison 
 
 EGIIED fay cieis dissin evih viens sine ses 2-46 Fied, leeth- visuyinseed sth t-gee 8-80 
 RA a ais scaxvepesnsese seins 2-46 LARS GNI oo an nvantankaay hee 5-60 
 MEIGS oye ckcccacessscvvetse 2-35 White lead... igs... nes sesers ee 6-60 
 Lamp black (vegetable Barytessiss sd cia aoe 4-45 
 
 ES ap ey aE i ape A 1:78 Ultramarine blue ............ 2:50 
 ERICA ACK Sib Sis0k chesnceals 1-80 
 
 47 
 
48 Blacks and Pitches 
 
 2. Fineness.—This as applied to pigments is usually understood 
 to refer to the degree of subdivision of the particles, and has an 
 important bearing on the paint industry. A certain degree of fine- 
 ness is, of course, essential before the mixture of solid pigment 
 with its liquid medium can be spread uniformly over a surface; 
 moreover, the hiding power of a pigment is inversely proportional 
 to the diameter of the particles, and furthermore the finer the 
 particles of a given pigment when mixed to form a paint, the greater 
 is its covering power. 
 
 The study of the ultimate size of particles, the determination of 
 their size and the application of the results to the study of problems 
 in the paint trade have engaged the attention of C. A. Klein and 
 W. Hulme *4 and C. A. Klein and J. Parrish,®> °§ whose conclusions 
 have appeared in recent publications. The chief methods which 
 have been proposed for determination of particle size are: 
 
 (i) Screening followed by elutriation or sedimentation. 
 
 (ii) Direct examination under a microscope by a method 
 due to Green.5’ A photomicrograph of a carefully prepared 
 mounted sample is taken, and this is further enlarged by means 
 of a stereopticon, the measurement being made of the particles 
 on the screen by means of a millimetre scale. Green introduces 
 a number of corrections in order to get a reliable value, but 
 several objections have been made to some of his conclusions. 
 
 (iii) A centrifugal method due to Svedberg and Nichols.* 
 
 (iv) Specific gravity suspension method due to Wiegner.®*® 
 
 (v) Air flotation. 
 
 Space forbids any full treatment of the subject here, as we are 
 
 concerned mainly with results obtained for black pigments and the 
 bearing these results have on paint manufacture. According to the 
 table by Klein and Parrish,®*° carbon black particles lie between 20 
 and 10uu (lu = 10° metre), with a limiting size of luu. Now it is 
 extremely unlikely that such a fine state of subdivision characterises 
 those black pigments which after manufacture require mechanical 
 srinding, such as the various charcoals, graphite, bone black, drop 
 black; the bearing of this will be seen later. 
 
 Klein and Parrish °* have pointed out the bearing of particle 
 size, the effect of grinding and the influence of air-surround of pig- 
 ments on the bulking value, which is of such importance in the paint 
 industry. The figures given in Table XII, taken from their paper, 
 are of interest, particularly the figures relating to oil absorption. 
 
 The authors discuss the various factors bearing on the bulking 
 
 os 
 
Black Pigments in Paint Manufacture 49 
 
 value, and particularly mention the influence of the air-surround of 
 the particles, which in the case of carbon black in the packed condition 
 amounts to 80%. 
 
 TaBLe XII. 
 Bulking Value and Oil Absorption of some Pigments. 
 
 Bulking value 
 
 Ibs./¢. ft. Air voids | Ot! absorp- 
 
 ) tion in gms. 
 
 Pigment. for packed ac oil Be 
 
 Loose. Packed. | Condition. pi Sait 
 
 White lead A ......... 44 125 71 12 
 POOR ICR Bones ccenesees 103 233 58 8 
 TARPS Ue vevevieesscakies 49 140 49 i3 
 fear pon Jlaels 5.055 sess. 13 3 80 150 
 Ng BO ee 19 53 58 - 46 
 
 3. Oil Absorption.—At the present time consideration of the 
 amount of oil or other medium required to convert a pigment into 
 a paste ready for application in painting is an important matter, 
 and is spoken of generally as the “ oil absorption ”’ of the pigment, 
 though this term is capable of a varied interpretation, as Cruick- 
 shank Smith points out. The exact method of determination of this 
 property leaves much to be desired. Calbeck ® distinguishes be- 
 tween primary and secondary oil absorption of pigments, the former 
 being the proportion of oil required to make a stiff paste, whilst 
 the latter refers to the additional amount of oil necessary to produce 
 a mixture of painting consistency. This author mentions the follow- 
 ing factors as determining the oil absorption: (1) air voids to be 
 filled, (2) wetting power of the oil, (3) nature of the surface of the 
 solid particles, (4) specific surface or fineness of the pigment, 
 (5) geometrical arrangement of the solid particles in the paste or 
 paint. 
 
 Gardner * has given some figures showing the percentage of 
 oil required for grinding pigments into average paste form, viz. : 
 Carbon black 82%, lampblack, 72%, drop (bone) black, 60%, bone 
 black 40%, graphite (pure), 40%, and for contrast one may cite 
 white lead (sublimed), 10%, blanc fixé, 30%, barytes (natural), 9%, 
 terra alba (gypsum), 22%. 
 
 4, Tinting Strength—The tinting strength of a pigment is a most 
 important desideratum to the paint manufacturer, and it is in virtue 
 
50 Blacks and Pitches 
 
 of their tinctorial properties that pigments transmit their own specific 
 hue or colour to other pigments or materials incorporated with them. 
 The tinting strength as applied to blacks is the measure of their 
 ability to impart a black hue to a definite weight of a standard white 
 pigment. In testing any given black it is the rule to compare its 
 tinctorial properties with a standard black pigment, and the following 
 procedure is that proposed in connection with the use of American 
 carbon black as a paint pigment.? 
 
 In making the test, weigh out accurately 0-100 gram of the black 
 to be tested, and 10-0 grams of standard zinc white kept specifically 
 for such a test as this. Transfer to a glass or marble slab, and add 
 from a burette exactly 3-5 c.c. of refined linseed oil. Mix with a 
 palette knife, and rub out thoroughly with the knife until no streaki- 
 ness is observed when successive small portions are spread on a clear 
 piece of window glass and viewed from the upper side. Ten minutes 
 is usually the time for this operation. Follow the same procedure 
 with the standard black. Then spread a small amount of each 
 mixing side by side on a clear glass, such as a microscope object glass. | 
 Examination of the samples from the other side of the glass, par- 
 ticularly at the line where they overlap, will show a difference of 
 tinting strength should any exist. 
 
 To make a quantitative estimation of the tinting strength of the 
 sample as compared with the standard, more white is added to the 
 stronger mixing until the colours match. A new sample of the 
 stronger black is then weighed out, using the calculated amount 
 of zinc white, and the process is repeated until mixes of the same 
 colour are obtained. If, for example, it was necessary to mix 15 
 grams of zinc white with 0-1 gram of the standard to match a mixture 
 of 10 grams of zinc white and 0-1 gram of the sample, the sample 
 has 662% the strength of the standard. 
 
 5. Colour.—By the term colour is meant the relative blackness 
 of the material when mixed with oil. In making the colour test, 
 0-3 gram of each of the blacks to be compared is added to each of a 
 like number of portions of 1-3 ¢c.c. of refined linseed oil from a burette. 
 Mix thoroughly by means of a palette knife, spread side by side on a 
 slip of glass, and compare the relative colour by viewing from the 
 upper side of the glass. 
 
 The measurement of the colour of a pigment in terms of some 
 agreed standards is possible by such means as the use of the Tinto- 
 meter (Lovibond), the Colourmeter and other means, to which 
 considerable attention has been paid in recent years. The reader 
 is referred to the more recent volumes on colour manufacture and 
 
Black Pigments in Paint Manufacture 51 
 
 colour testing for a fuller insight into the details of colour 
 measurement (cf. Klein and Aston’s volumes). 
 
 In considering the uses of the black pigments in paint-making, the 
 purpose for which the paint is intended is of importance, and 
 Cruickshank Smith mentions the following uses to which such a paint 
 may be applied : 
 
 (a) Decorative work requiring a jet-black used chiefly as a 
 self-colour ; 
 
 (6) Tinting or staining, requiring a finely-ground and very 
 strong paint suitable for making grey or slate-coloured tones; 
 
 (c) Protection of wood, iron or stone, or as an important 
 ingredient in paints to be used in protecting one or other of these 
 surfaces. 
 
 For decorative work alone, bone black is strongly favoured, carbon 
 black being added sometimes to secure depth of colour. Often, 
 however, such pigments are adulterated with barytes and whiting 
 for cheapness. 
 
 Black paints for tinting and staining purposes must generally 
 be lampblack or carbon black, and in conjunction with a white base 
 the former gives a bluish-grey tone and the latter a brownish-grey 
 tone. Blacks vary in colour and in their tinting strength—the less 
 volatile matter a black contains the blacker its colour. But the 
 tinting strength of blacks high in volatile matter is usually higher 
 than that of blacks containing more free carbon. This fact may be 
 due to the way in which the volatile matter is dispersed through the 
 black; this point will be discussed more fully in the next chapter 
 in connection with the use of blacks as ink pigments. 
 
 Carbon black and lampblack absorb far more oil in grinding than 
 is the case with mineral and bone blacks; this is partly on account 
 of their finer state of subdivision, but against this must be set the 
 fact that paints from the former pigments have, in consequence of this 
 finer state of subdivision, greater hiding power. Generally also the 
 former blacks are unsurpassed for use in making certain \black 
 varnishes on account of their superior tinting strength; carbon 
 black has three times the tinting strength of some of the charcoal 
 blacks, such as one from ground coconut charcoal. 
 
 As protective coverings, black paints are not used for general 
 purposes, except in the case of graphite, which has been mentioned 
 in this connection in Chapter II. In the preparation of black dis- 
 tempers for stone and wood, however, and in the manufacture of 
 stove polishes, both carbon black and lampblack find great use. 
 
52 Blacks and Pitches 
 
 The so-called grinding in oil of the blacks, or, more properly 
 speaking, their incorporation in the oil or paint medium, can be carried 
 out in the ordinary granite triple-roller paint mill in the case of 
 paints which contain the relatively coarser mineral, bone or charcoal 
 blacks. Where very fine lampblack or carbon black is concerned, 
 the ordinary granite triple-roller mill is useless. Rollers with a 
 very smooth face are used, and these are usually enclosed under 
 a hood or cover, so that loss of pigment, owing to its extreme fine- 
 ness, is prevented. The author has experienced cases where such 
 covering was necessary even in the use of very finely-ground vege- 
 table charcoal. 
 
 The following tests have been suggested ? in connection with the 
 use of carbon black as a paint pigment : 
 
 Carbon Black for Paint Manufacture. 
 
 Chemical tests. Physical tests. 
 Moisture ......... less than 5% Tinting strength ...... not less than 
 PARED ons o chil axa chen less than 1-:25% 95% of the 
 strength of 
 standard. 
 
 In connection with the use of carbon black as a pigment in air- 
 craft manufacture, the following specification is extracted, by the 
 kind permission of the British Engineering Standards Association, 
 from their Report No. D. 30, November, 1921, official copies of 
 which can be obtained from the Secretary of the Association, 28 
 Victoria Street, Westminster, 8.W.1, price 2d., post free. 
 
 BRITISH ENGINEERING STANDARDS ASSOCIATION 
 British Standard Specification for Avrrcraft Material. 
 
 CARBON BLACK 
 
 1. Description.—The material shall consist of gas carbon black, 
 containing not less than 96% of carbon. 
 
 2. State of Division—The material shall be in a fine state of 
 division, uniform in character and free from gritty particles. Five 
 parts of the pigment shall grind to a stiff paste with 4 parts of 
 castor oil (British Standard Specification 2 D. 5). 
 
 3. Moisture, etc—The loss in weight on heating in an oven at 
 100° C, (212° F.) for 1 hour shall not exceed 3%. 
 
 4. Matter Soluble in Water.—The material shall contain not more 
 than 0-1% of matter soluble in water and the aqueous extract shall 
 show no acid reaction to methyl orange. 
 
 The test shall be carried out as described in Appendix I. 
 
 5, Ether Extract.—The material shall contain not more than 0- 5%, 
 
Black Pigments in Paint Manufacture 53 
 
 of matter soluble in methylated ether (sp. gr. 0-720). This shall be 
 determined by extraction in a Soxhlet apparatus for 2 hours. 
 
 6. Ash.—The amount of ash left on ignition shall not exceed 
 oy 
 
 7. Colour—The colour of the material shall closely match 
 that of the Standard,* when determined by the method given in 
 Appendix II. 
 
 Note.—By “match” in the above clause, shall be understood approxi- 
 mately matching when compared with the Standard in diffused daylight. 
 
 8. Tinting Strength.—The tinting strength of the pigment shall 
 
 be not inferior to that of the Standard,* when determined by the 
 method described in Appendix III. 
 
 APPENDIX I. 
 Method for the Estimation of Matter Soluble in Water. 
 
 Two grams of the material shall be moistened with alcohol and 
 then boiled for 5 minutes with 200 c.c. of neutral distilled water and 
 filtered. The reaction of the filtrate shall be determined towards 
 methyl orange. An aliquot part of the filtrate shall then be 
 evaporated to dryness and the residue weighed. 
 
 AppEnpDIx II. 
 Method for the Determination of Colour. 
 
 Four parts of the pigment shall be ground to a paste with 3 
 parts of castor oil (British Standard Specification 2 D. 5). 3:5 
 grams shall then be thinned with 50 c.c. of the following nitro- 
 cellulose medium, and the resulting product brushed on doped 
 Linen Aeroplane Fabric (British Standard Specification 3 F. 1). 
 
 Nitro-cellulose syrup, British Standard Specification 2 D. 8. 23-2 grams 
 
 Butyl acetate pe ne ie oD: €s L642ec. 
 Alcohol # << a 2 Dobe 1b wee 
 Benzol a ot A 2 D. 10. Is sec: 
 Acetone = a “e 2D 22, 29s 
 
 APPENDIX III. 
 Method for the Determination of Tinting Strength. 
 
 One part of the pigment shall be mixed with 80 parts of zinc 
 oxide (British Standard Specification D. 27) and ground to a paste 
 with 50 parts of castor oil (British Standard Specification 2 D. 5). 
 
 This Specification was adopted by the Sectional Aircraft Com- 
 mittee on the 21st October, 1921, and approved on behalf of the 
 Main Committee on the 5th November, 1921. 
 
 * The Standard consists of a piece of doped and varnished fabric pre- 
 pared as described in Appendix II, which can be obtained on application to 
 the Superintendent, Royal Aircraft Establishment, Farnborough. 
 
54. Blacks and Pitches 
 
 When considering artists’ pigments, the qualities most desirable 
 are permanence, brilliance, purity of tone; and permanence is, of 
 course, often a matter of conditions. In manufacturing the artists’ 
 black pigments the most frequently used blacks are carbon black, 
 lampblack and bone black.®! 
 
 REFERENCES. 
 
 53 “ Industrial Applications of Wetting Power,’ 5th Colloid Report, Bri°. 
 Assoc. Adv. Sci., 1923, 38. 54 Journ. Owl and Colour Chem. Assoc., 1920, 
 21, Vol. III. °° Jbid., 1924, 45, Vol. VII. *°* Jbid., 1924, 46, Vol. VIL. 
 5? Journ. Franklin Institute, 1921, 192, 637. 58 Svedberg and Nichols, 
 Journ. Amer. Chem. Soc., 1923, 45, 2910. 5 Wiegner, Landw. Versuchsst., 
 1918, 91, 41. ® ‘* The Oil Absorption of Pigments,’ Calbeck, Chem. Met. 
 Eing., 1924, 31, 377. 61 May, Chem. and Industry, 1924, 48, 82. 
 
 Bibliography—Blacks as Paint Pigments. 
 
 ‘* Determination of Distribution of Particle Size,’ Kelly, J. Ind. Eng. 
 Chem., 1924, 16, 928. J. Parrish (communication to discussion), Journ. Ol 
 and Colour Chem. Assoc., 1925, 55, Vol. VIII. ‘‘Numerical Determination of 
 the Fineness of Pigments,’ Werl, Moniteur de la Peinture, 1924, No. 116, 309. 
 “The Chemistry and Technology of Paints,” M. Tech., 1916. ‘‘ Modern 
 Pigments and their Vehicles,” Maire, 1908. Papers on the Measurement of 
 Colour, Journ. Oil and Colour Chem. Assoc., 1921, 27, Vol. IV. Jbid., 1922, 
 36, Vol. V. 
 
CHAPTER VII 
 BLACK PIGMENTS FOR INK MANUFACTURE 
 
 Different Classes of Work requiring Printing Ink—Properties of Blacks— 
 Long and Short Blacks—Chemical, Physical and Practical Tests on 
 Printing Ink Blacks—Some Photomicrographs of Ink Pigments. 
 
 It seems probable that the very earliest known inks had lampblack 
 or some similar form of carbon as their base; all the ancient 
 Egyptian inks appear to have been essentially carbonaceous in 
 character. A. Lucas ® has examined the remains of ink of the 
 sixteenth century B.c., and shown it to be of carbon basis. Accord- 
 ing to Chinese historians, Chinese, or Indian ink as we term it, 
 was made as far back as between 2697 B.c. and 2597 B.c. Vitru- 
 vius,®* the Roman engineer (30 B.c.—a.D. 14), describes the prepara- 
 tion of an ink for decorative purposes, the soot from pitch-pine being 
 the basis. Gradually, however, the transition from carbon inks to 
 those made from gall nuts and iron salts took place in Europe, and 
 this transition was probably complete by the Middle Ages so far as 
 inks for writing purposes are concerned. For a full account, how- 
 ever, of the development of the ink-making industry from the earliest 
 times to the present day the reader must turn to Mitchell and 
 Hepworth.*4 
 
 With the invention of the printing press and its introduction 
 into England by Caxton, lampblack as a pigment for printing ink 
 came into universal use, and was used exclusively for this purpose 
 until the advent of carbon black about 1864, since which date the 
 latter pigment has been used to an increasing extent, and is now 
 the principal pigment for black printing ink, which is, of course, the 
 most important ink used in printing, the ink being composed of the 
 black pigment in a vehicle such as boiled linseed oil, other oils 
 used according to requirements being perilla, tung and some mineral 
 oils. The main desiderata are thus the pigment and the oil or 
 varnish in which it is mixed. 
 
 Printing inks are used in three main classes of work, viz. : 
 
 1. Those for ordinary typographic work, 
 
 2. Those for lithographic printing, 
 
 3. Those for depressed surface printing, e.g., in copper-plate 
 engraving work. 
 
 The modern rotary printing-presses require an ink that will dry 
 sufficiently rapidly to enable the presses to be operated at a high 
 speed, that will flow freely, possess great covering power and make 
 instantaneous and legible impressions.2° One lb. of carbon black 
 
 mixed with 8 lbs. of oil and other materials will give sufficient ink 
 . 55 
 
56 Blacks and Pitches 
 
 to print 2,250 copies of a 16-page newspaper of ordinary size or 
 90 copies of a 300-page octavo book. 
 
 Certain carbon blacks give a “‘short”’ ink, 7.e., an ink of buttery 
 consistency which does not flow rapidly, and such an ink is eminently 
 suitable in lithographic and offset work, in slow-speed presses, and 
 for most half-tones. Lampblack does not give the best consistency, 
 and is too grey in colour. On the other hand, there are carbon 
 blacks especially desirable where fast-running presses are in use, 
 such blacks yielding a fluid “ long”’ ink, which has opacity enough 
 to give a black letter. According to Underwood and Sullivan,® 
 if a pigment mixed with a large quantity of oil remains stiff or cannot 
 be drawn out into a string between the fingers, such pigment is said 
 to be “ short,” and generally it happens that pigments showing this 
 property are not suited to ink manufacture. On the other hand, 
 an ink with a good flow and the property of being drawn out into a 
 thread between the fingers is said to possess length, and the black 
 which imparts these characteristics is said to be a “ long ”’ black. 
 
 The properties of the various black pigments and their value 
 as ink-making pigments have been ably summarised by Underwood 
 and Sullivan ®° and are given in tabular form thus : 
 
 TaBLE XIII. 
 Properties of Blacks. 
 
 Oil 
 
 Name. Top hue. Under hue. absorption. Fineness. 
 
 Bone black ...... Greenish-black | Brownish-black | Fairly low | Should be fairly 
 fine, %.e., there 
 should still be 
 some grain 
 
 Vine black ...... Greenish-black | Brownish-black | Fairly low — 
 
 darker than 
 bone black 
 
 Carbon black ... Deep black Brownish-black High — 
 
 Lampblack ...... Deep black Brownish-black High — 
 
 Mineral black ... | Brownish-black | Decided brown ; Fairly low | Should be an im- 
 palpable powder 
 
 Magnetic pigment | Brownish-black | Decided brown Low 
 
 Manganese black | Brownish-black | Decided brown Low 
 
 Name. Flow. Shortness. Tastpers Atmospheric 
 to light. influences. 
 
 Bone black ...... Flows fairly well Fairly short No effect No effect 
 
 Vine black ...... Flows fairly well Fairly long e is 
 
 Carbon black ... Poor Short fe * 
 
 Lampblack ...... Poor Short * . 
 
 Mineral black ... Good Fairly long 5 a 
 
 Magnetic pigment Good Long re re 
 
 Manganese black Good Long 
 
Black Pigments for Ink Manufacture 57 
 TaBLE XIII (continued). 
 
 Abrasive 
 
 Name. | Drying. Smoothness. qualities Incompatibility. 
 
 Bone black ...... Exerts no Does not make Quite Mixes with 
 
 drying action a smooth ink abrasive everything 
 
 Vine black ...... a Does not make Quite es 
 
 a smooth ink abrasive 
 
 Carbon black ... | nes Works up very | Not abrasive ‘i 
 
 smooth 
 
 Lampblack ...... an Works up Not abrasive Ba 
 
 smooth 
 
 Mineral black ... . Does not make Quite = 
 
 a smooth ink abrasive 
 
 Magnetic pigment ve Works up Not abrasive oe 
 
 very smooth 
 
 Manganese black Fr: Works up Not abrasive Re. 
 
 very smooth 
 Name. Value as an Ink-making Pigment. 
 
 Bone black ......... Of great value as a plate-printing ink material, although it must 
 be mixed with vine black for colour and to give the proper working 
 qualities. 
 
 Vine black ......... Of great value as a toner to mix with bone black to give colour 
 and working qualities to black plate-printing inks. 
 
 Carbon black ...... The most important typographical black; in fact it is the base of 
 all black typographical inks at the present day. 
 
 Lampblack ......... | Not much used at present, as its place has been taken by the cheaper 
 
 but similar carbon black. 
 Mineral black ...... 
 Magnetic pigment | +} Used principally to mix with other blacks. 
 Manganese black . 
 
 Such physical qualities and the methods of evaluating them as 
 specific gravity, fineness, oil absorption, tinting strength and colour 
 have already been discussed in the preceding chapter, and need 
 not be dealt with again here, though in one way or another all have 
 an interest to the ink-maker. 
 
 Chemical tests have been dealt with in Chapter IV, and in con- 
 nection with the amounts of volatile matter in blacks it may be 
 mentioned that the halo sometimes to be observed round letters in 
 some old books and papers has been attributed by Irvine 7° to the 
 presence of tarry compounds such as chrysene, C,,H,, (m. p. 250°C.), 
 and pyrene, C,,H,, (m. p. 148° C.), in the black used. Whilst there 
 are no definite specifications laid down to which carbon blacks for 
 ink-making must conform, the following have been suggested and 
 are here re-printed from the Bulletin 2: 
 
 Printing Ink. 
 
 Chemical tests. Physical tests. 
 Moisture ......... less than 5:0% COIOUE accvas must match standard. 
 BBO pteccersst ces less than 0-1% Tinting 
 Acetone extract . less than 0:1% strength . must equal standard. 
 
 CSPI Vs voce ums enone wesiesetense none. 
 
58 Blacks and Pitches 
 
 Practical Tests—The black when made into ink must have satis- 
 factory working qualities as determined by an actual run on the 
 press for which the ink is intended. The ink must have satisfactory 
 transfer, tack, drying properties, colour, and must print a sufficient 
 number of pages per pound. The oil must not separate from the 
 pigment and there must be no offset or smutting. 
 
 Testing Methods.—Chemical and physical tests are performed as 
 previously described. Practical tests are to be made on the press 
 for which the ink is intended. Specifications for tests to be made 
 for which half-tone black ink is used are as follows : 
 
 1. Non-separation of Oul from Pigment.—The oil or varnish should 
 not separate from the pigment either on the face of the type or cuts 
 or in the fountain, but should be short enough to break up readily 
 in the distribution and not “ string.” 
 
 2. Transfer.—In transferring from type or cuts to paper the ink 
 should leave the face of the type or cuts reasonably clean. 
 
 3. Hardness.—Ink should dry hard on the paper in 8 hours to 
 admit of easy handling without damage or injury to the work, and 
 should not pull the coating or the face from the paper, nor the face 
 from the roller. 
 
 4, Drying—Ink should not dry on the forme, rollers or distribu- 
 tion, so that it may be easily removed therefrom. | 
 
 5. Offset or Smutting.—The ink must be able to carry sufficient 
 colour to print clean and sharp, without offset or smut on sheets 
 _ falling on top from the pressfly or in piling the work. 
 
 6. Colour.—The ink must dry a deep, solid carbon (not aniline) 
 black, and not turn grey, nor have a metallic sheen or lustre, nor 
 blister the face of the paper. 
 
 7. Quantity Required.—The weight of the amount used must be 
 noted and averaged on a basis of 5,000 printed pages. 
 
 Methods to be used in making the Practical Tests.” 
 
 1. The practical test of half-tone black ink shall be made on the 
 flat-bed presses in use in the Government Printing Office. 
 
 2. The test shall be made on coated book paper of the size, 
 weight and quality in general use in the Government Printing 
 Office. F 
 
 3. The type or cut forme shall be previously “made ready ” and 
 the press otherwise in good condition to make a satisfactory run. 
 
 4. The forme, rollers, distribution, and ink fountain shall then 
 be thoroughly washed and cleaned. The ink to be tested shall be 
 

 

 
 Fic. 13.—Photomicrograph showing Agglomerated Particles 
 of Short Carbon Black, 2 hrs. after preparation on the 
 Slide. Magnified 500 diameters. 
 
 
 
 Fic. 14.—Photomicrograph showing Dispersed Particles of 
 Long Carbon Black, 2 hrs. after preparation on the Slide, 
 Magnified 500 diameters. 
 
Black Pigments for Ink Manufacture 59 
 
 weighed before being placed in the fountain. The quantity to be 
 tested should be sufficient to run not less than 3 hours, and prefer- 
 ably a run of 5 hours should be made. 
 
 5. Ink that will separate the oil or varnish from the pigment 
 on the face of the forme or in the fountain will not be accepted. 
 
 6. To be satisfactory, ink, under the impression, should transfer 
 from the face of the type or cuts to the paper, leaving the face of the 
 type or cuts reasonably clean. It should be heavy in body, should 
 feed well, and have sufficient “tack ’’ to dry on the paper rapidly 
 enough, while printing, to avoid the necessity of using slip sheets; 
 but it should dry hard on the paper in 8 hours, so that the work 
 can be handled easily without damage or injury to the printing. 
 It must not pull the face or coating from the paper and leave it on 
 the forme or pull the face from the rollers. It should be removed 
 easily from the forme, rollers and distribution, and must be able 
 to carry sufficient colour without offset or smut, and print clean 
 and sharp. 
 
 7. The ink, to be satisfactory, must dry a deep, solid carbon 
 (not aniline) black, and not turn grey, nor have a metallic sheen or 
 lustre, nor blister the face of the paper. 
 
 Photomicrographs of carbon black have been taken by Dr. 
 Reinhardt Thiessen and are reproduced here by the courtesy of the 
 U.S. Department of the Interior from Bulletin 192. Under the 
 microscope, freshly-prepared mixtures of thin lithographic varnish 
 with short and long black respectively at first appear precisely 
 similar. They consist of ultra particles or of agglomerates of two 
 _or three particles, but after a few minutes there is a progressive 
 agglomeration of the particles to be noticed in the case of a “ short ”’ 
 black and in about an hour there are groups with upwards of a 
 hundred particles grouped together. In contrast, the “long ” 
 black remains completely dispersed even after an interval of several 
 hours. These differences are admirably illustrated in Figs. 13 
 and 14. 
 
 Long blacks are usually made with cylindrical burners and a 
 cool flame, a method tending to the production of a black high in 
 volatile matter, and it is suggested that these impurities prevent 
 carbon particles from agglomerating. The tendency towards 
 agglomeration is materially altered by the character of the vehicle 
 in which the blacks are suspended. Lampblack shows the same 
 tendency to agglomerate as do short carbon blacks, and this fact 
 is borne out by the appearance in Fig. 15. As a rule, however, 
 
60 Blacks and Pitches 
 
 lampblacks make long inks, so that the tendency to agglomerate 
 does not account entirely for the difference in behaviour of different 
 carbon blacks and of lampblack. 
 
 Under the microscope lampblack and different grades of carbon 
 black present much the same appearance. ‘There are differences in 
 the amounts of coarse particles, but the different behaviour of 
 the various blacks may be due to a difference in the constitution of 
 the ultramicroscopic particles, possibly a difference in size, in 
 attraction between the particles, and in surface energy at the oil- 
 black interface, but the reliable data available hardly warrant the 
 putting forward of even a tentative explanation of the different 
 behaviour of “ long ”’ and “ short” blacks. 
 
 Preliminary study of (1) viscosity, (2) cohesion, and (3) adhesion 
 of mixtures of black pigment and oil has been entered upon, and in 
 some measurements which have been made long blacks are shown 
 to have lower cohesion than short blacks, which is what one would 
 expect from their behaviour. It seems reasonable to surmise that 
 the physical considerations will outweigh the purely chemical 
 in any hypothesis which satisfactorily explains the behaviour of 
 different blacks, not only as ink pigments, but as paint pigments 
 too. 
 
 REFERENCES. 
 
 62 Analyst, 1922, 47, 9. ® De Architectura, lib. VII., 10.  ‘“‘ Inks, 
 their Composition and Manufacture,” C. A. Mitchell and T. C. Hepworth, 
 1916. 8° “The Chemistry and Technology of Printing Inks,” N. Underwood 
 and J. V. Sullivan, 1915. 
 
 Bibliography—Blacks as Ink Pigments. 
 
 ‘** Composition, Properties and Testing of Printing Inks,’”’ U.S. Bureau of 
 Standards Circular 53, 1915. ‘‘ Carbon Black for Ink,”’ Gas Age, New York, 
 1920, May 10th. ‘‘ Where the Printer Gets His Ink: America’s Carbon- 
 black Industry,” Scientific American, New York, 1920, April 38rd. Thorpe, 
 ** Dictionary of Applied Chemistry,” Vol. ITI., 1922, p. 639. 
 

 
 Fic. 15.—Photomicrograph showing Agglomerated Particles 
 of Lampblack. Magnified 500 diameters. 
 

 
 ub 
 
 
 
CHAPTER VIII 
 CARBON BLACK AS A RUBBER PIGMENT 
 
 Factors concerned in the Use of Compounding Ingredients in Rubber— 
 Tests for Carbon Black in Rubber—Change in Elastic Constants— 
 Stress—strain Relationships. 
 
 Prior to the year 1914 carbon black and lampblack were used in 
 the rubber industry only for colouring purposes, and to only a small 
 extent. The presence of mineral ingredients in a fine state of sub- 
 division in vulcanised rubber has long been recognised as capable of 
 imparting desirable characteristics to such rubber, and a knowledge 
 of the relative effects produced by different ingredients that may be 
 used is of great importance.*® 
 
 _ Zine oxide, which had early attained a position as an important 
 filler for rubber, became too costly soon after the outbreak of the 
 World War, and it was then shown that carbon black could be success- 
 fully substituted as a filler in rubber. The favourable results 
 achieved increased the use of carbon black enormously, and the 
 present tendency is to manufacture black tread tyres instead of 
 white ones.2° Since 1922 the demand from the rubber industry 
 for carbon black has been so heavy that there has been a consequen- 
 tial expansion in the production of carbon black from natural gas in 
 the United States, the production in 1923 being an increase of 
 104% over the production in 1922.°? 
 
 Carbon black as a rubber pigment is now used to the extent 
 of 3—20%, according to the purpose for which the rubber is 
 required. On a volume basis, carbon black (sp. gr. 1-8) costs 
 only one-third of the price of zinc oxide (sp. gr. 5-6, say), but 
 actually in practice a greater volume of carbon black is used than 
 of zinc oxide, so that the resulting mix with the black contains less 
 rubber per unit volume than the zinc oxide mix. 
 
 According to Greider,®® the principal factors governing the 
 reinforcing effects of all compounding ingredients in rubber appear 
 to be: 
 
 1. Quantity of pigment or volume ratio pigment to rubber 
 phase. 
 
 2. Average particle size (specific surface). 
 
 3. Wetting of pigment by rubber, or adhesion, surface 
 tension. 
 
 4. Flocculation of the pigment during incorporation or 
 vulcanisation. 
 
 5. Particle shape. 
 
 6. Uniformity or size-frequency distribution. 
 61 
 
62 Blacks and Pitches 
 
 The influence of particle size on specific surface is of great 
 importance in the rubber industry, and Wiegand,® in discussing 
 the effect of surface area on the rubber stress-strain curve, gives the 
 following figures : 
 
 Apparent Surface. 
 
 Barytes . . 30,480 sq. ins. per c. in. of pigment. 
 Carbon Black . 1,905,000 _,, * “a 
 
 The method of formation of carbon black is, of course, responsible 
 for its fine state of subdivision and the corresponding enormous 
 surface that ensues. Theoretically carbon black should be an ideal 
 filler for rubber in virtue of its fine state of subdivision, because 
 Ditmar 7° has found the following advantages accrue from the use 
 of finely divided pigments in rubber mixtures : 
 
 1. The nearly homogeneous mixing. 
 
 2. The accelerated rate of cure. 
 
 3. The reduction in cost by the increase possible in the per- 
 centage of admixture. 
 
 4, Increase in elasticity. 
 
 5. The intensification of the colouring power. 
 
 6. The smoother surface obtained, and greater resistance to 
 abrasion. 
 
 7. The longer life of the cured rubber. 
 
 Now in all the above respects carbon black has been found to be 
 an ideal rubber pigment, and it is claimed for it, in addition, that 
 it protects rubber from the action of light and, furthermore, may 
 even retard oxidation. 
 
 The following tests have been suggested ? for use in testing carbon 
 black for the rubber industry : 
 
 TaBLE XIV. 
 Carbon Black as a Filler for Rubber. 
 Chemical tests. Physical tests. 
 
 Moisture ......... less than 4% (rit cu duer a none (should com- 
 Acetone extract. less than 0-5% pletely pass through 
 At iipipieasaeen. less than 0:25% a 100-mesh sieve and 
 7 feel as an impalpable 
 powder when rubbed 
 
 under the finger). 
 
 Tinting 
 
 strength . not less than 90% of the 
 strength of standard. 
 
Carbon Black as a Rubber Pigment 63 
 
 Practical Tests. 
 
 Rubber mixes are made up containing equal weights of the 
 sample to be tested and of the standard. Mixes are cured under 
 exactly the same condition. The finished sheet is tested for tensile 
 strength, per cent. elongation, toughness, and resistance to abrasion. 
 
 Wiegand 71 and Schippel ** have investigated the volume increase 
 of compounded rubber under strain, and also the stress-strain curves, 
 and the results indicate generally that the finer the state of sub- 
 division the larger the proportion of inert filler which can be mixed 
 with rubber without resultant loss of tensile strength. In the case 
 of carbon black, apparently up to 40% may be compounded, and 
 the rubber is thus hardened and stiffened without loss of tensile 
 strength. The volume increase at 200% elongation varies from 
 1-46% in the case of carbon black and 1-76% in the case of lamp- 
 black to 13-3°% in the case of barytes—azinc oxide apparently behaves 
 somewhat abnormally. 
 
 TABLE XV. 
 The Results for Mixings containing 20 Volumes of Pigment 
 
 Displace- Total Volume 
 ; Apparent ment of increase % 
 Pigment. peice. stress-strain area at 200% 
 curve. " | elongation. 
 Carbon black ...... 1,905,000 42 640 1-46 
 Lampblack ...... 1,524,000 4] 480 1-76 
 Red oxide ......... 152,400 29 355 1-9 
 Zinc oxide ......... 152,400 25 530 0:8 
 bo) a 60,900 17 410 4-6 
 Fossil flour ...... 50,800 14 365 3°5 
 a are 30,480 8 360 13:3 
 
 With the exception of zinc oxide, therefore, the increase in volume 
 which occurs in compounded rubber when under strain is lowest 
 when the particles are in the finest state of subdivision. The advan- 
 tage of fine pigments relative to coarse ones is probably accounted 
 for by the greater tendency of the compounded rubber, when 
 stretched, to separate from the large particles.” 
 
 The stress-strain curve for rubber reproduces in a simple manner 
 the relation between the load and the elongation, and the displace- 
 ment of the stress-strain curve refers to the increase in load sup- 
 ported at a given elongation, and is thus a measure of the resistance 
 
64 Blacks and Pitches 
 
 to stretching. In respect of this property the behaviour of carbon 
 black and lampblack is in accordance with the size of their 
 particles. 
 
 W. W. Vogt and R. D. Evans ™ have investigated the stress— 
 strain relationship and Poisson’s Ratio for all the common rubber 
 compounding ingredients. For homogeneous isotropic substances 
 the elastic constants and Poisson’s Ratio are the same in all direc- 
 tions in the substance, but there are other substances where these 
 constants and Poisson’s Ratio have different values, and such latter 
 substances are termed anisotropic.’® As a result of their investiga- 
 tions, these authors find the following fillers are isotropic, viz. : 
 carbon black, lampblack, zinc oxide, barytes, lithopone, whilst the 
 following are anisotropic, viz.: graphite, mica, magnesium car- 
 bonate. It will be noted that graphite does not fall within the 
 same category as carbon black and lampblack. 
 
 Similar differences were noted by the authors in regard to volume 
 increase under strain and permanent set; the permanent set was 
 higher for mixtures with anisotropic fillers than for those with 
 isotropic ones, and mixtures containing anisotropic fillers on tearing 
 behave as though laminated. 
 
 This anisotropy in properties is postulated as being due to the 
 shape of the particles; particles with two dimensions notably 
 greater than the third tend to align themselves during calendering 
 with their longer axis in the direction of the calender, and their 
 smaller dimension perpendicular to the plane of the calender. In 
 consequence, different values for elastic constants and for Poisson’s 
 Ratio are obtained for a compounded rubber, according as to 
 which of three mutually perpendicular directions is chosen to make 
 the test, 7.e., with the grain, across the grain, or vertical to the 
 grain. 
 
 The ultimate particles of lampblack and carbon black tend to 
 approximate to the spherical shape from their very method of 
 formation, and one would expect them therefore to be isotropic. 
 The reader who is further inclined to pursue this study must consult 
 some of the better-known works on rubber technology, to which 
 domain the study properly belongs. 
 
 REFERENCES. 
 
 66 Indiarubber Journal, 1919, 58, 19. 67 See Appendix I, p. 171, 172. 
 68 J. Ind. Eng. Chem., 1924, 16, 151. ®* Can. Chem. Journal, 1920, 4, 160. 
 70 Chem. Zeitung, 1921, 45, 943. 71 J. Ind. Eng. Chem., 1921, 18,118. 7 Ibid., 
 1920, 12, 33. 7% Annual Reports, Soc. Chem. Ind., 1919, 4, 324. 7 Vogt 
 and Evans, J. Ind. Eng. Chem., 1923,15, 1015. 75 See Searle, «‘ Experimental 
 Elasticity,’ Camb. Univ. Press, 
 
Carbon Black as a Rubber Pigment 65 
 
 Rubber Pigments—Bibliography. 
 
 Depew and Ruby, J. Ind. Eng. Chem., 1920, 12, 1156. Green, Journ. 
 Franklin Inst., 1921, 192, 637. Green, J. Ind. Eng. Chem., 1921, 18, 1130. 
 ** Physics of Rubber,”’ Wiegand, ibid., 1922, 14, 854. ‘“‘ Fineness and Bulk 
 of Pigments,’ Gardner, Circular 148, Paint Manufs. Assoc., U.S., 1922. 
 ** Determination of the Particle Size of Pigments,’? Vogt, Indiarubber World, 
 1922, 66, 347. Luttringer, Caoutchouc et Gutta-Percha, 1922, 19, 11,308. 
 Green, Chem. and Met. Hng., 1923, 28, 53. Greider, J. Ind. Eng. Chem., 
 1923, 15, 504. ‘‘ Thermal Properties of Various Pigments and Rubber,” 
 I. Williams, J. Ind. Eng. Chem., 1923, 15, 154-157. Weigel, U.S. Bureau 
 of Mines, Technical Paper 296. Endres, J. Ind. Eng. Chem., 1924, 16, 1148. 
 G. L. Cabot, Indiarubber Review, 1924, 24, Nov., p. 84. ‘* Determination of 
 Distribution of Particle Size,’’ W. J. Kelly, Ind. Eng. Chem., 1924, 16, 928. 
 Indiarubber Review, 1923, 28, 754. 
 
CHAPTER IX 
 PITCHES AND BITUMINOUS MATERIALS 
 
 Introduction—Factors Involved in Classification—Definitions—Complete 
 Classification. 
 
 Introduction and Classification 
 
 On various parts of the earth’s surface, notably in Syria, Egypt, 
 Trinidad, Bermudez, California and Utah, occur mineral deposits, 
 some of which are hard, brittle and black, whilst others are soft 
 and viscous, black fluid masses. Allied to these in respect of many 
 of their properties, and notably as regards applicability, are those 
 black residues which arise out of the distillation, frequently 
 destructive, of such familiar substances in the organic world as 
 coal, wood, peat, petroleum, bone, fatty acids and greases. ‘The 
 terms Pitch, Asphalt, Asphaltum, Bitumen are variously and some- 
 what indiscriminately applied to these natural and manufactured 
 products, and in consequence a certain confusion arises at times. 
 
 Many of these natural deposits have been known in the East 
 from time immemorial, where their first use appears to have been 
 in the nature of a cement for joining objects together. The 
 word asphalt is traceable to Babylonian times, to the Greek 
 aéodadroc, through late Latin asphaltum to the French asphalte 
 and ultimately the English asphalt. (Milton, Paradise Lost, i, 729, 
 refers to “asphaltus’’?). The term bitumen originated in 
 Sanskrit. 
 
 The earliest recorded use of asphalt by the human race goes 
 back to the Sumerians, who were the pre-Babylonian 7° inhabitants 
 of the Euphrates valley. 1t was also known to the early Persians 
 and to the ancient Egyptians, who used it in connection with their 
 burial rites.77 In the Old Testament there is reference to it in 
 connection with the Tower of Babel (circa 2000 B.c.) and in con- 
 nection with incidents relative to the infancy of Moses (circa 
 1500 B.c.).78 
 
 From its earliest mention in the literature of Greece, Rome and 
 Palestine, the typical asphalt of commerce was the solid bitumen, 
 found on the shores of the Dead Sea, of the following proximate 
 composition 7° : 
 
 Carbon : . Tie 
 Hydrogen . ; . ae 
 Oxygen : , ; . dey, 
 Nitrogen. : : : a ot fy = 
 
 and closely analogous is the Egyptian bitumen : 
 66 
 
Pitches and Bituminous Materials 67 
 
 Carbon s . ; j 1 8h38% 
 Hydrogen . ; fag eenB2%, 
 Oxygen é A ; ; - 56-26% 
 Nitrogen. ; ; : 5 QE 
 
 According to Nebuchadnezzar, his father Nabopolassar (625— 
 604 B.c.) laid the first asphalt block pavement of which any record 
 is extant.°° Hannibal of Carthage (250 B.c.) used asphalt in war- 
 fare, and Pliny the Elder of Rome about a.p. 100 makes reference 
 to asphalt, which, he says, must be glossy and black. 
 
 Asphalt was discovered in Cuba ® in 1535, and the Pitch Lake in 
 Trinidad ®° by Sir Walter Raleigh in 1595. In 1661 we find refer- 
 ence to the production of wood tar on the large scale by the dry 
 distillation of wood, and later, in 1681, the discovery of coal tar 
 pitch was made in England, a patent relative thereto being taken 
 out by Becher and Serle. *° 
 
 During the nineteenth century many advances were chronicled 
 in connection with our knowledge of asphaltic and pitch-like sub- 
 stances, and the first use of the asphalt pavement is to be recorded 
 in London, Paris and the large cities of U.S.A. Such natural 
 bitumens as gilsonite were discovered in Utah in 1885, and the 
 same century saw the manufacture and use of stearine pitch and 
 petroleum pitch—residues of the distillation of fatty acids and 
 petroleum respectively. | 
 
 As already mentioned, owing to the loose and indiscriminate 
 way in which the terms “ bitumen,” “tar,” “ pitch,” “ asphalt,” 
 etc., have been used for centuries, coupled with the fact that the 
 physical properties and the chemical composition of the substances 
 so designated were little understood, the problem of accurately 
 defining and systematically classifying the various pitches and 
 bituminous substances has proved extraordinarily baffling. At 
 the present time there is no uniform or accepted standard of nomen- 
 clature, though much has been done towards evolving order out of 
 chaos by the work of Abraham,*! Clifford Richardson *? and the 
 British Engineering Standards Association.*? In his recently 
 published book, P. E. Spielmann **« has reviewed at some length 
 and somewhat chronologically the various attempts that have been 
 made to secure uniformity of definition and nomenclature of 
 - Bituminous Substances. The present author ®* in an earlier 
 publication used the term bitumen to define a class of substances, 
 not necessarily solid, occurring in nature, and which are soluble 
 in carbon disulphide, chloroform and other neutral liquids, and 
 consisting essentially of compounds of carbon and hydrogen asso- 
 
68 Blacks and Pitches 
 
 ciated frequently with compounds of oxygen, sulphur and nitrogen 
 with possibly traces of mineral matter, the latter consisting of 
 compounds of iron and alumina. Adopting this definition, one 
 would then. regard the asphalts as mineral matters containing 
 bitumen in intimate association. Richardson has suggested the 
 term “residual pitches ” for those closely allied artificial products 
 arising during the distillation of organic bodies. 
 
 Broadly speaking, the foregoing is in substantial agreement 
 as regards its main outlines with the more elaborate and detailed 
 system of definition and classification adopted by Abraham,*® 
 and the present author has adopted in this volume the system of 
 Abraham, except in respect of certain substances which have 
 been omitted from that writer’s scheme for reasons which will be 
 indicated later. 
 
 The following criteria, viz., origin, physical properties, solubility 
 and chemical composition, form the basis for a preliminary classi- 
 fication indicated in the accompanying table : 
 
 TABLE XVI ® 
 
 Mineral 
 Native | Veuotable 
 is Animal 
 Origin Evaporation (fractional distillation) 
 Destructive distillation 
 Pyrogenous {eae in a closed vessel 
 Blowing with air 
 Colour in Light (white, yellow or brown) 
 mass Dark (black) 
 Liquid 
 Consistency | Viscous 
 or hardness | Semi-solid 
 Solid 
 Conchoidal 
 Fracture Hackly ‘ 
 Waxy 
 Physical Lustre | Resinous 
 properties Dull 
 Adherent 
 Feel | Non-adherent 
 Unctuous (waxy) 
 Oily (petroleum-like) 
 Odour Tarry 
 Volatility Non aclatile 
 Fusible 
 Fusibility {Difieuiy fusible 
 Infusible (melts only with decomposition) 
 Non-mineral constituents in carbon disulphide 
 Solubility {Distillate at 300 to 350° C. in sulphuric acid (¢.e. “‘ sulphona- 
 tion residue ’’) 
 Hydrocarbons (compounds containing carbon and hydrogen) 
 feet bo hanes ee (compounds containing carbon hydrogen 
 Ne and oxygen 
 eS ie ihe Grvptallinabic paraffins (crystallise at low temperatures) 
 Mineral matter (inorganic substances) 
 

 
 
 
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 AJP AT} 9Tqnjos AJOATy O14ST104 snoues 
 g[qeiiea | -vredmog Ajosie'y -ereduoy | -oereyy ATtO — pmbry -o1hg IVT, 
 10778Ur wouINnyzIq 
 [VIOUIUE FILM pozvIoOsse soumTy -o1hd 
 -ou10s §=‘seIpoq =poyeuosAxo e[qnjosutr Q[TPRTOA quoreqpe | [Np 02 |Ajeareared oryjeydse 
 surureyuoo ‘suoq1eo01pA HT —_ Ajosre'y e[qisnyuy -UON oh -uoN | Snourtsey | -wWoO SATION -UON 
 1ozyeu [eIoUTUA 
 YjIM pozeroosse souwljyouos weuINn4Ig 
 ‘saIpoq poyeuesAXO UWIOI} OTT eq njosur O[IFVIOA quereype | [mp 09 |Ajoatqzered -o1h4d 
 Ayperyueysqns ‘suoqireoorpAy{ — Ajosre'T e[qisnyjuy -UON — -uON | SNoursey | -WoD eAyeN jo4teydsy 
 *19}4eUL [eIOUTUL 
 [WM poyeloosse somrjyouros 
 ‘suyjered ojqestteysA1o pue 
 seIpog poyeuesAxo WOT] 9eIT aqqe eyqnyos 9[qisny O[TFVOA quoreqpe Ajoatyered 
 Ajjeryueysqns ‘suoqieoorpAyy | -Jeprsuog Ajesiey =| Apymnowiqe -UON — -UON | SnouIsoy |} -WOD aarzen joqqpeqdsy 
 199} eU 
 [eroulNr «Ss IMA Ss PO} UTOOSSe 
 souljyouos ‘suyjered o[qestt O[IRIOA Tp 07 
 -[eysA19 OU IO 97491] Surureqzu0o -u0u quor1sype | snoursel snoues 
 ‘seIpoq poyeuesAxo WOI} 90IF a[qz 9[qnjos Ajoaty -uou 09 | ‘sorqorrea -o1hd 10 
 Ayjeryaeysqns ‘suoqieoorpAy | -Jeprisuog Ajosie'yT gqisny =| -eaedu0g — quereypy | JoprexE | 9Tqere, eaten | qeqdsy 
 10}{VUI [BIOUTUT WIIA 
 PpezyeIoosse SOUITJOWIOS ‘soIpoq pieq 
 poyeussAhx0 utezuoo you Avu 9[qnjosut O[TPB[OA quorsype | [np oz jApeatyeared weumn4yiq 
 Jo Avur yoryM ‘suoqieoorpAyT — Ajoaryrpoy | = 9Tqrsnyuy -UON —_— -uoN | Snoulsey | -WoD yreq eatyeny | -o1kg 
 197j{VUI [eIOUTUL e[qIsny 
 YyIM pozeroosse souwlyoutos ore (pros 03 | (4zep 
 ‘setpoq poyeuesAxo WOIT 90IF aqe 9Tqnyjos SOLJOLIVA ; pmbr]) | 09 94317) 
 Ajjeueysqns ‘suoqieoompAy | -roprsuog AjosieyT Iopieyy o[qeieA —_ — — gqeeva | o[qeleA | oaATZeN, | UaUINAIG 
 “O81 TSID ‘oprydynstp *97IeNngTSsu00 “k 
 O o0SE-00E | Wow UT | jexoura-uou | *AUWTNeIOA *“mopo [20g ‘arysnT 5 hdc ; 2 
 “won odunop Na Be ae "uO | seourmniea 
 *AAITIqnTos *sotjzedoid peorséyg 
 
 
 
 
 
 op TAX Wavy, 
 
70 Blacks and Pitches 
 
 In Table XVII the most important types of bituminous sub- 
 stances and pitches are classified according to the features 
 enumerated in Table XVI. Abraham, in his system of classifica- 
 tion, has included the Mineral Waxes amongst the bituminous 
 substances, but since these waxes, such as ozokerite and montan 
 wax, are so closely akin to paraffin wax, at any rate in general 
 physical properties and to a considerable extent in chemical com- 
 position, it appears preferable to exclude these waxes from the 
 scheme of classification. Furthermore, the present author does not 
 deem it advisable to include, as Abraham does, Petroleum. It 
 appears better to consider petroleum as the parent substance of 
 certain bitumens rather than as a species of bitumen itself, and 
 there is ample evidence to support this preference, and consequently 
 petroleum is not included in Table XVIII. 
 
 The definitions which follow are taken from Abraham’s classi- 
 fication,®® and they help to a clear understanding of Table XVII 
 and to that of Table XVIII, which follows in further elaboration. 
 
 Bitumen.—A term applied to native substances of variable 
 colour, hardness and volatility; composed of hydrocarbons and 
 substantially free from oxygenated bodies; sometimes in associa- 
 tion with mineral matter, the non-mineral constituents being 
 fusible and largely soluble in carbon disulphide; and whose 
 distillate, fractionated between 300° and 350° C., yields considerable 
 sulphonation residue. 
 
 This definition includes petroleum and native mineral waxes, 
 which the author, however, prefers not to include in any system 
 of classification of bitumens. 
 
 Pyrobitumen.—A term applied to native substances of dark 
 colour, the word “ pyrobitumen ”’ implying that the substances, 
 when subjected to heat, will give rise to bodies resembling bitumens 
 in their solubility and physical properties. They are comparatively 
 hard and non-volatile; composed of hydrocarbons, which may or 
 may not contain oxygenated bodies; sometimes associated with 
 mineral matter, the non-mineral constituents being infusible and 
 relatively insoluble in carbon disulphide. 
 
 Asphalt.—A term applied to a species of bitumen and also to 
 certain pyrogenous substances of dark colour, of variable hardness, 
 comparatively non-volatile ; composed of hydrocarbons, substantially 
 free from oxygenated bodies; containing relatively little or no 
 crystallisable paraffins; sometimes in association with mineral 
 matter, the non-mineral constituents being fusible, and largely 
 soluble in carbon disulphide; and whose distillate, fractionated 
 
Pitches and Bituminous Materials 71 
 
 between 300° and 350° C., yields considerable sulphonation 
 residue. | 
 
 _ Asphaltite—A species of bitumen, including dark-coloured, com- 
 paratively hard and non-volatile solids; composed of hydrocarbons, 
 substantially free from oxygenated bodies and crystallisable 
 paraffins; sometimes associated with mineral matter, the non- 
 mineral constituents being difficultly fusible, and largely soluble in 
 carbon disulphide, and whose distillate, fractionated between 300° 
 and 350° C., yields considerable sulphonation residue. 
 
 Asphaltic Pyrobitumen.—A species of pyrobitumen including 
 dark-coloured, comparatively hard and non-volatile solids; com- 
 posed of hydrocarbons, substantially free from oxygenated bodies; 
 sometimes associated with mineral matter, the non-mineral con- 
 stituents being infusible and largely insoluble in carbon disulphide. 
 
 Non-asphaltic Pyrobitumen.—A species of pyrobitumen, includ- 
 ing dark-coloured, comparatively hard and non-volatile solids; 
 composed of hydrocarbons, containing oxygenated bodies; some- 
 times associated with mineral matter, the non-mineral constituents 
 being infusible and largely insoluble in carbon disulphide. 
 
 Tar.—A term applied to pyrogenous distillates of dark colour, 
 liquid consistency, having a characteristic odour; comparatively 
 volatile; of variable composition; sometimes associated with 
 carbonaceous matter, the non-carbonaceous constituents being 
 largely soluble in carbon disulphide, and whose distillate, frac- 
 tionated between 300° and 350° C., yields comparatively little 
 sulphonation residue. 
 
 _ Pitch.—A term applied to pyrogenous residues, of dark colour, 
 viscous to solid consistency; comparatively non-volatile, fusible; 
 of variable composition; sometimes associated with carbonaceous 
 matter, the non-carbonaceous constituents being largely soluble in 
 carbon disulphide, and whose distillate, fractionated between 300° 
 and 350° C., yields comparatively little sulphonation residue. 
 
 The preceding definitions allow construction of the detailed 
 classification in Table XVIII. This latter agrees with that of 
 Abraham, except that petroleum and native mineral waxes have 
 not been included, whilst the non-asphaltic members (peat, lignite, 
 coal and their shales) have been omitted, as likewise also have 
 the pyrogenous waxes, though included by Abraham. The present 
 author considers all such substances quite outside such a classi- 
 fication. 
 
Blacks and Pitches 
 
 72 
 
 ‘[e00 snourur 
 
 -njIq Wo} oYOo Surmyoejnueul ur usA0-ox09 Jonpoid-Aq Woy poonporg 
 *[BO0O 
 
 SNOUTUIN}IG UOT, SVS SULIMJOBJNUBUL UI $}10401 OSNOY-ses WOIJ poonpolg 
 
 ‘so[eys snourumyiqorAd jo uoye[[NsIp oatjonsysep 943 Aq poonpoig 
 
 ‘([209 UMOIG) OPUSTT Jo UOTZRI[SIP SATjoNIYsep ey Aq poonporg 
 
 ‘geod Jo UO4RI[IIsIP 9ATpONAYsSep oy} Aq poonpoig 
 
 ‘spoompiey JO UOT{I[MSIP oATJONAYSop oy} Aq poonporg 
 
 *SIOJIUOD JO SOOT PUB SPOOM OY} JO UOTIRI[YSIP PATONIYSOp oy} Aq poonpoig 
 "SBS-10VBM 
 
 poyemnqievo Zurmnyovjnueur ur sinodea umejo1ed Surgovio Aq poonpoig 
 
 ‘seS-[10 SulmMyoejnueuUL ut sinodea umnoeposjod Suryoesro Aq peonpoig 
 
 
 
 ‘opeurumopeid s109448Ur [BIOUTYL | 
 
 Buryeey uo ostrourAjodep you seoq 
 
 ‘ummejorjed UOT} Suyevoy uo Ajyred sostrouA[odoq 
 ‘gjqnjosur pue | g]qnjos pue 
 
 ‘end Ajjereues) | oTqisny Sururooeq “Buryeey uo sostrourA[odocqy 
 
 eiqeyruodes Ajyaed—Asoqqny 
 
 “9[QN[OSUI pus e[qISNyUT 
 
 poalloqd 
 Bt en yty 
 
 
 
 earnduit oymb 03 oing 
 eind Aje7e1opoul OF ong 
 
 ‘umNng[Orjed UOT, POATIOG, 
 eind Ajoute1y xi 
 
 ‘syyeydse uvy yuiod-suisny seysty e@ OAB_L 
 
 
 
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 io Axel ‘ouoysourl] ‘euojspues ‘pues Jo uoMJod [eYURIsqns e@ SuTUTeJUOD 
 "(qys1em Arp oyy 
 
 uo %ol uey} sse[) 10q9euL [esouTUT pozeroosse wor cory AjoATyVreduIOg |eind Ajires 10 o1ng 
 
 
 
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 re} poompieyy 
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 soreys 
 
 snouruin}iq 
 -o1dd onyeudsy 
 oyiuosdury 
 OPTOnTy 
 
 O7[IZ}IN AA 
 OV1109V[ 
 
 oPIUIBYBIL) 
 youd oour[y 
 OFYUOsITY) 
 
 Io}yeUr [eIOUTUI 
 YyIM po werossy 
 
 *1LOQULOP[ 
 
 SIC], 
 
 suoumnjziqoikd 
 onjeydsy 
 4 
 
 
 
 seyypeydsy 
 
 sqyeydse 
 OATYEN 
 
 ‘soroodg 
 
 8978[[19STp 
 snouesoi4 gq 
 
 suouInyIq 
 -o1hg 
 
 susuInyig 
 
 *snuey 
 
 
 
 og SHONVESHNS SQONIWOLIG JO NOLLVOIMISSVT) ATLA IdWO/) 
 
 TAX Pav 
 
73 
 
 Pitches and Bituminous Materials 
 
 
 
 eSsvoIs [OOM UMOIG JO UOTYR{[TSIp uIeEs O44 Aq pouTezqo enprIseyy yqovid [oO AA 
 ‘esvoid YoVlq U0}400 JO UOTZBI[YSIP Urve}s oy. Aq poureqyqo onprsey | yoqtd poos-u09309 
 ‘splow A978} Jo uOTWeT[MSIP urve4s oy} Aq pouTezqo onprsey | yoqrd proe-Aneg 
 ‘e10zIUOd Jo des snoulsel oY} JO UOTZE[[I4SIp [eryavd oy Aq poureyqo onprseyy youd utsoxy 
 youd 1e4-0u0g 
 youd 184 
 -[809 S¥vs-1e0npoig 
 youd 124 
 -[B00 sovUINy-yselq 
 youd 14 
 -[B09 U9A0-9309 
 ‘srBqy OATZoodser youd 14 
 ey} Jo uoeyystip 10 uoyeiodeae jenred oy Aq poureyqo senprsery -[809 SyIOM-sex) 
 youd 1eq-oTeyg 
 youd 1e4-091UsrT 
 youd 1284-480g 
 youd 184-Ppoo AA 
 yoy 
 I2@4-SeB-1078 A 
 youd 1e4-se3-[19 
 
 
 
 "SJLOJOI PEsO[D UI oy ]IzZJINM SurstzeutAjodep Aq poonporg | ypeydse o4rytzqan AA 
 
 ‘plow otinydjns 441M soqeq][y4s1p 
 waneporjed Jo uonvoytind 944 Ut pouteyqo ‘espny{s plow oy} UIOIy poonporg syeydse ospnyig 
 ‘summeorjed oneydse puv oseq-poxrm jo uolye][4SIp wreeys oyy Aq poonpoig | syteydse in ang 
 syyeydse 
 ‘s[IO [enpIser poyeoy YSnomy} are Sutmofq Aq poonporg | umofored umoig 
 ‘uuneforjed onpeydse. 
 JO UOT}R][YSIP Uree4s OY IO ‘uINe[OTJed oseq PoOXIU Jo UOTPET[INSTP-uTeE}S 
 
 io Aap oy} ‘umefored onteydse-uou jo uorneyystp Arp eyy Aq poonpoig S[IO [eNnpIsersy 
 
 
 
 *sou0g JO UOTVI[NSIP oATONIYsop oy} Aq peonporg 1e4-9u0g 
 1B4-[209 
 
 ‘jeoo WOI} SVs-Loonpoid Surinjoejnueul ur stoonpoid-se3 ulo1y poonposg ses-r1oonpolg 
 "B09 IB}-[209 
 
 SNOUIUIN}Iq YJIM s[ejour Zuyjours uodn seovuInj-yse[q woz poonpoig eovUINj-4sB[q 
 
 soyoud 
 
 syeydse 
 snousso1k gg 
 
 *‘sonpIses 
 snousso14g 
 
74 Blacks and Pitches 
 
 REFERENCES. 
 
 76 “ Civilisation of Babylonia and Assyria,” Morris Jastrow, jun., Phila- 
 delphia, 1915. 7? ‘‘ Memoires-Délégations en Perse,’ ed. by J. de Morgan, 
 Vol. XITI., Paris, 1912. 78 Genesis xi. 3 and Exodus ii. 3. 79 Thorpe, 
 ‘** Dictionary of Applied Chemistry.” 8 ‘‘ Asphalts and Allied Substances,” 
 Herbert Abraham, New York, 1918, Chaps. land II. 8! “ The Classification 
 of Bituminous and Resinous Substances,” by H. Abraham, J. Ind. Eng. 
 Chem., 1913, 5, 11. ® ‘‘The Modern Asphalt Pavement,” by Clifford 
 Richardson, New York, 1908. 8 ‘‘ British Standard Nomenclature of 
 Tars, Pitches, Bitumens, and Asphalts, when used for Road Purposes,” 
 London, April, 1916. 8 ‘‘ Bituminous Substances,”’ by Percy E. Spielmann, 
 1925, Ernest Benn, Ltd. §®4 H. M. Langton, Journ. Ow and Colour Chem. 
 Assoc., 1919, 2, No. 7. 
 
 Pitches and Bituminous Substances—Bibliography. 
 
 ** Asphalts and Allied Substances,”’ by Herbert Abraham, D. Van Nostrand 
 Company, New York, 1918. ‘‘ Trinidad and Bermudez Lake -Asphalts,”’ 
 Barber Asphalt Paving Company, Philadelphia. ‘‘ Asphalts,” by T. H. 
 Boorman, New York, 1908. U.S. Department of Agriculture, Office of 
 Public Roads, Circular No. 93, 1911. Proc. American Society for Testing 
 Materials, 1916, 16, Part I, 594. ‘‘ Bituminous Substances,” by Perey E. 
 Spielmann, Ernest Benn, Ltd., London, 1925. 
 
CHAPTER X 
 THE CHEMISTRY OF THE BITUMENS AND PITCHES 
 
 Paraffinoid, Aromatic and Naphthenic Hydrocarbons—Nitrogenous, Oxy- 
 genated and Sulphur Compounds. 
 
 THE bitumens and pyrobitumens occurring in nature as well as the 
 somewhat related manufactured pitches are complex mixtures of 
 chemical compounds containing the elements carbon and hydrogen— 
 the Hydrocarbons—in varying proportions and combined in a 
 variety of ways. Some of the compounds may contain the elements 
 oxygen, sulphur and nitrogen, and smaller or larger amounts of 
 extraneous mineral matter are usually found in intimate associa- 
 tion. Hydrocarbons occur in all types of bituminous substances— 
 _ in fact, they predominate—and they are briefly considered below : 
 Hydrocarbons.—The following series are known to occur : 
 
 C, Hons. Sertes—Paraffins. 
 
 | Name. Formula. M.p.(°C.). B. p. (°C.). 
 Liquid : ) 
 Pentane CHio — +38 
 Hexane Cea, _ +69 
 Heptane CH. - +98 
 Heptadecane C,,H3¢6 22 —- 
 Solid : 
 Octodecane C,,H3¢ 28 317 
 Nonadecane CoHs0 32 330 
 Eicosane Cop Has 37 205 
 at 15 mm. 
 
 Dimyricyl Coo Hi00 102 -- 
 
 The liquid members and their isomers are associated together in 
 such petroleums as that of Pennsylvania and in certain asphalts, 
 whilst some of the solid members occur in low-temperature tars 
 from coal. . 
 
 C,H., Series—Olefines (one double bond). 
 
 Name. Formula. M.p.(°C.). B.p.(°C.) 
 Inquid : 
 
 _ Amylene and isomers CH —— +-39 
 Hexylene oi C,H. — 69 
 Heptylene C,H,, — 95 
 Kikosylene ) Cap Ha — 314 
 
 Solid : 
 Cerotene Cy,Hs4 +58 
 
 Melene C5oH 69 +62 375 
 75 
 
76 Blacks and Pitches 
 
 These and their isomers are present in some American petroleums 
 in small amount. 
 
 C,H» Series—Acetylenes (one triple bond). 
 
 Name. Formula. Bepo(tas: 
 LInquid : 
 Crotonylene C,H, 27 
 Isopropylacetylene C;H, — 
 
 Several of the higher members are found in Texas, Louisiana 
 and Ohio petroleums and in coal tar, 
 
 C, Hon» Series—Diolefines (two double bonds). 
 
 Name. Formula. Bop G3: 
 Allylene (Propadiéne) CH,-.C:CH, Gas 
 Divinyl (Erythrene) CH,:CH-CH:CH, 5 
 Piperylene («-Methylbutadiéne) CH,:CH*CH:CH-CH, +42 
 Isoprene (8-Methylbutadiéne) CH,-CH:-C(CH;):CH, +35 
 Conylene CH,:CH-CH,CH:CH-CH,CH,CH, 126 
 
 These hydrocarbons occur in tars and in certain petroleums. 
 
 CrH2,-4 Serves—Olefinacetylenes. 
 
 Some of these occur in certain types of Californian petroleum. 
 
 C,H., Series—Naphthenes or Cycloparaffins or Polymethylenes. 
 
 Name. Formula. M: p. OC). Bopp iae: 
 Cyclopropane (Trimethylene) CH<te —126 —35 
 Cyclohexane (Hexamethylene) oe +6 81 
 Cyclononane (Nonomethylene) CH,- CH, CH, Clon: 171 
 
 CH,—CH,—CH,—CH, 
 
 These occur in American mixed-base and asphaltic petroleums 
 (including Ohio, Californian and Canadian) and in fatty acid 
 pitches. 
 
 C,H2,-2 Series—Polycylic Polymethylenes. 
 
 These are usually associated with members of the previous 
 series. 
 
The Chemistry of the Bitumens and Pitches ja 
 
 C,H», Series—Cyclo-olefines (one double bond). 
 
 H 
 
 These include cyclo-ethylene, Oa ee, 
 
 CH—CH 
 propylene, C,H,,.< jee 
 y 5“ °CH,—OH,—CH, 
 They occur in Texas oils and in certain asphalts. 
 
 panne’ | 
 , and cyclo- 
 s—CH, z 
 
 C,H», Series—Monocyclic Benzenes. 
 
 Name. Formula. Bop. C0. 
 as 
 Benzene C,H, or L | 80 
 é * 
 _ Toluene or Monomethylbenzene C,H,:CH, or | hack > 110 
 Xylenes C,H,(CH3). 
 CH, CH, CH 
 \ 
 or Dimethylbenzenes | as Clon ( 
 eee Ae are etl 
 CH, 
 ortho- meta- para- 
 b. p. 142°. b. p. 139% b. p. 138°. 
 Trimethylbenzenes (3) C,H.(CH3)s 
 Hexamethylbenzene C,(CHs)¢ 305 
 
 Members of this series and their respective isomers are present 
 in coal tars, water gas tar and other pyrogenous distillates. Traces 
 have been found in many petroleums and in lignite tar. 
 
 C,H en-g to C,Hn-39 Sertes—Monocyclic and Polycylic. 
 
 C,,H,,- 3 Serves, of which the principal member is phenylethylene, 
 C,H;°CH:CH,. 
 
 C,H,;-1. Sertes—the Indenes, of which the principal members 
 are indene, C,H,°C,H., b. p. 182° C., hydrindene, C,)H,49, b. p. 176° C., 
 and the methylindenes and dimethylindenes. 
 
 Cr, Hon-1, Sertes—the Naphthalenes, the principal member of 
 
 Se Lars Ks 
 which is naphthalene, C,,H,, represented thus : © | ; 
 fe 
 
 C,Hon-14 Series—the Diphenyls, the principal member of which 
 
 is diphenyl, C,,H,,, represented as Gas Rais: The next member 
 
 of the series is methyl diphenyl, C,,H,°CH3. 
 
78 Blacks and Pitches 
 C,Hen-14 Series—the Acenaphihenes, the first member of which 
 
 FG Was 2) 
 is acenaphthene, C,.H,), which is represented as Ms ih age ee 
 H,C—CH, 
 
 CrHon-1, Series—the Diphenylenes, which include fluorene, 
 
 C,H 
 C,3H,5, represented as fe “NOH, or \Z SCH, ; stilbene, 
 
 C,H,*CH:CH:C,H,. 
 C fe tS potas 8s Anthracenes, of which the chief niger 
 
 vA ny ree 
 are anthracene, C,,H,,, represented as | |... dea, Shae 
 \A ON 
 
 P< y 
 phenanthrene, C,,H,, represented as \/ Wa wae b. p. 340° C.; 
 ( \CHs / 
 
 retene, C,,H,5; oe ib. p. 3507 CG. 
 
 Pay 
 ee 
 C3H, 
 C,Hon-29 Serves—principal member fluoranthene, C,;H jo. 
 C,Hon-22 Sertes—principal member pyrene, C,H 4. 
 ntLon-24 Sertes—principal member chrysene, C,gH4o. 
 The hydrocarbons of all the foregoing series, C,H,,-, to 
 C,,Hon-39, all occur in coal tar and the higher members of many 
 
 ie a ¥e ~ 
 of the series in coal-tar pitch. Indene, | _ vn C,H,'°C,H,, 
 i , 
 
 CH, 
 and styrene, C,H ;*CH‘CHg, have been identified, and their respective 
 amounts present determined by R. L. Brown and R. D. Howard ® 
 recently in samples of water-gas tar, whilst J. M. Weiss and C. R. 
 Downs *° have isolated 4% of phenanthrene, C,,H,), and 0:1% 
 of diphenyl, (C,H;)., from coke-oven tar. 
 
 Oxygen-containing Compounds. 
 
 Water occurs in small quantities in most native asphalts, in 
 crude tars and to some extent in pitches. 
 
- 
 
 The Chenustry of the Bitumens and Pitches 
 
 Alcohols : 
 
 Methy] Alcohol, CH,-OH. 
 Ethyl Alcohol, C,H,-OH. 
 
 Cetyl Alcohol, C,H3°OH, b. p. 344° C. 
 Ceryl Alcohol, C,,H;,-OH, m. p. 79° C. 
 Myricyl Alcohol, C,,H,,;-OH, m. p. 88° C. 
 
 79 
 
 The higher waxy members of this series are present in wool 
 
 wax or grease and in wool grease pitch and in certain bitumens. 
 
 Ketones : 
 
 Acetone, CH,°CO:CH;, and its higher homologues are found in 
 
 wood tar and certain lignite and blast-furnace tars. 
 
 Phenols : 
 Phenol, C,H;OH, b. p. 182-6° C. 
 Cresol or Methyl Phenol (3 isomers), CH,°C,H,-OH. 
 Dihydric Phenols (3 isomers), C,H,(OH),. 
 Guaiacol, OH:C,H,-OCHs. 
 Trihydric Phenols, C,H,(OH)s. 
 
 These and higher homologues and derived esters are found in 
 coal tar and lignite tar, whilst guaiacol and other esters of the 
 cresols and the trihydric phenols are found in wood tar and wood- 
 
 tar pitch. 
 
 Fatty Acids : . 
 C,,H,,0, Series : 
 
 Acetic Acid, CH,-COOH, b. p 137-9° C. 
 
 Lauric Acid, C,,H,,-COOH, m. p. 43-6° C. 
 Myristic Acid, C,,H,,-COOH, m. p. 53-8° C. 
 Palmitic Acid, C,;H,,-COOH, m. p. 62:6° C. 
 Daturic Acid, C,,H;,;>COOH, m. p. 59-5° C. 
 Stearic Acid, C,,H;,;-COOH, m. p. 69-3° C. 
 Arachidic Acid, C,,H,,,;>COOH, m. p. 77° C. 
 Behenic Acid, C,,H,,;COOH, m. p. 83:8° C. 
 Lignoceric Acid, C,,H,,,;COOH, m. p. 80-:5° C. 
 Cerotic Acid, C,,H;,,;COOH, m. p. 77-8° C. 
 Montanic Acid, C,,H;,-COOH, m. p. 83° C. 
 Mellisic Acid, C,,Hz9*COOH, m. p. 91° C. 
 
 Acetic acid is present in wood tars, whilst the higher members 
 
80 Blacks and Pitches 
 
 of this series from palmitic acid upwards, together with their corre- 
 sponding lactones and esters, are found in fatty acid pitches, and 
 the members from cerotic acid upwards in wool grease pitch and 
 in certain bitumens. 
 
 C,Ho,-20. Series : 
 Amongst the higher members are 
 
 Oleic Acid 
 Elaidic Acid fC17Hlse' COOH 
 Erucic Acid, C,,H,,;COOH 
 
 Some of the higher members of this series are found in fatty 
 acid pitches. : 
 
 Resin Acids.—These are of somewhat uncertain structure, but 
 the abietic acids and their homologues containing a phenanthrene 
 or retene hydrocarbon structure are known to occur in rosin oil, 
 and are probably present, together with their esters, anhydrides 
 and lactones, in wood tars, especially pine tar, in pine pitch and in 
 resin pitch. Various constitutions of the type represented by 
 Griin, viz., 
 
 CH, 
 COOH-C/ \c(CH,), 
 CH 
 
 Hol Ac 
 
 ae 
 Boe 
 CH 
 HC ey 
 
 CH, 
 
 Cy Hs.02, have been attributed to abietic acid, but at present the 
 constitution of this and of allied resin acids is undecided, though 
 an able summary of our present knowledge has been contributed 
 by C. E. Soane.’? 
 
 A number of highly complex resinous and oxygenated com- 
 pounds are found in many of the soft naturally occurring asphalts, 
 but their complete separation and identification have not yet been 
 achieved. 
 
 Sulphur Compounds : 
 Carbon_Disulphide, CS,, b. p. 46-5° C. 
 
 Thiophene, C,H,8, represented as ul 2 b. p. 84° C. 
 S 
 
The Chemistry of the Bitumens and Pitches 81 
 
 a-Thiotolene, CH,°C,H,'S or \, ) On pits DOELZS 0 
 Oe 
 B-Thiotolene, CH;°C,H,'S or x A ep. bie. 
 
 Thioxenes and their isomers, sees 
 Methyl Sulphide, (CH,),8, b. p. 37-5° C. 
 Ethyl Sulphide, (C,H,),S, b. p. 92° C. 
 Methyl Mercaptan, CH,-SH, b. p. 6° C. 
 Ethyl Mercaptan, C,H,;SH, b. p. 36-2° C. 
 
 Some or all of the above compounds are known to occur in 
 certain petroleums, their derived asphalts, in certain pyrobitumens, 
 notably in coal tar and lignite tar, and probably in the corresponding 
 pitches. 
 
 Nitrogenous Compounds : 
 Aniline, C,H;NH,, b. p. 183° C. 
 fos 
 Pyridene, C,;H;N, represented as a yp b. plo C. 
 
 Picolines or Methyl Pyridines (3 isomers), CH,°C,H,N. 
 Lutidines or Dimethyl Pyridines (4 isomers), (OH, }e C, HN. 
 Collidines or Trimethyl Pyridines, (CH,),°C;H,N. 
 NH 
 Indol, C,H,N, represented as aid ‘ 
 N 
 
 A: a _ 
 & is 
 
 Isoquinoline, C,H,N, represented as Seve o and their 
 NS 
 
 f 
 
 Quinoline, C,H,N; represented as 
 
 homologues. 
 N 
 Acridine, C,,;H,N, represented as ‘ be Se: 
 ER Re NS 
 Pyrrol, C,H;N, represented as es , b. p. 180—131° C. 
 NH 
 Carbazol, C,,H,N, b. p. 238° C. 
 
 Very small amounts of some of the foregoing are found in 
 
82 Blacks and Pitches 
 
 fatty acid pitches, though all are present in coal tar; some are 
 present in petroleum asphalts and lignite tar and the less volatile 
 in coal-tar pitch and lignite-tar pitch. 
 
 It is evident that the chemistry of bituminous substances and 
 pitches is very complicated in view of the fact that their com- 
 position is not definite, but consists of mixtures of numerous 
 chemical compounds in varying amounts. No single bitumen or 
 pitch has been completely separated into its constituent compounds, 
 though, of course, the composition of coal tar is to a great extent 
 known. 
 
 According to Abraham,* the element nitrogen is rarely present 
 in excess of 2% of the non-mineral constituents of a bituminous 
 substance. Asphalt, asphaltites and pyrobitumens contain varying 
 amounts, up to a maximum of about 1-7%, of nitrogen, and tars 
 and pitches, except fatty acid pitches, may contain up to 1% of 
 nitrogen. 
 
 The amount of sulphur in bituminous wieieape such as native 
 asphalts, asphaltites and asphaltic pyrobitumens may vary from 
 0 to 10%, but sulphur compounds are practically absent from all 
 the pyrogenous pitches, 7.e., those from wood tar, fatty acids, 
 coal tar. 
 
 According to the investigations of O. C. Ralston,®® the per- 
 centages of carbon, hydrogen and oxygen in bituminous compounds 
 appear to follow some well-defined laws. 
 
 For fuller information on the chemical structure, properties, 
 reactions and physical constants and general characters of the 
 various hydrocarbons, oxygen-containing, nitrogenous and sulphur 
 compounds mentioned in this chapter, the reader is referred to any 
 of the well-known standard text-books of organic chemistry. 
 
 REFERENCES. 
 
 85 Industrial and Eng. Chem., 1923, 15, 1147. 8° Ibid., 1923, 15, 1022. 
 8? Journ. Oil and Colour Chem. Assoc., 1922, 5, No. 35 (cf. Volume on Resins 
 in this series). §8* Technical Paper No. 93, U.S. Dept. of the Interior, Bureau 
 of Mines, 1915. 
 
CHAPTER XI 
 
 METHODS OF TESTING BITUMINOUS MATERIALS 
 AND PITCHES 
 
 American and British Standardisation—Physical, Heat, Solubility and 
 Chemical Tests and their Uses. 
 
 THE tests which an investigator will apply to any given material 
 may serve as a means of identification, as a criterion of purity, 
 as an aid to manufacturing control or as an indication of the use 
 to which the material may be applied. In this last-named con- 
 nection, many of the tests to be applied to a bituminous material 
 or pitch will depend on whether the material is to be used in manu- 
 facturing a bituminous varnish or a japan, in preparing a water- 
 proofing material for a damp course or in highway construction. 
 | The standardisation of testing of asphalts, solid and semi-solid 
 bitumens, tars and pitches was undertaken in the United States 
 a very considerable time ago by the American Society for Testing 
 Materials (A.S.T.M.) and very valuable work was achieved. More 
 recently in this country, thanks to the pioneer work of the Insti- 
 tution of Petroleum Technologists, the task of fixing standard 
 tests for Petroleum and its various products has been started and 
 considerable progress has been made. The work of the committee 
 engaged on the task has been reported upon by A. E. Dunstan.* 
 Many of the standard tests of the A.S.T.M. have been recommended 
 for use by this British Committee, who have, however, deferred 
 their decision in the case of many of the tests pending further 
 reports from sub-committees. 
 
 The present author in this volume has adopted the tests and 
 the numbers attached thereto as given by Herbert Abraham *° in 
 his volume on “ Asphalts and Allied Substances,” and the reasons 
 that have prompted this course are that many of the tests given 
 are already the adopted standards of the A.S.T.M., and are recom- 
 mended by the British Committee already referred to. Further- 
 more, Abraham’s scheme of testing is very full and embraces tests 
 adequate for all the industries concerned in the use of bituminous 
 materials and pitches. 3 
 
 In the following pages most of the tests are given only in bare 
 outline, as considerations of space forbid any other treatment, but 
 full description of tests with illustrations of apparatus to be used 
 are given by Spielmann.®** Moreover, it is not the purpose of the 
 present volume to give detailed descriptions of apparatus and 
 technique largely described in the well-known standard works on 
 Chemical Analysis and Experimental Physics. 
 
 83 
 
84 Blacks and Pitches 
 TABLE XIX. 
 Tests to be Applied to Bituminous Substances. 
 Test No. Description. Test No. Description. 
 Physical characteristics : Solubility tests : 
 Test 1 | Colour in mass Test 21 | Solubility in carbon di- 
 Test 2 | Homogeneity sulphide 
 Test 3 | Appearance of surface aged | Test 22 | Carbenes 
 one week Test 23 | Solubility in 88° petroleum 
 Test 4 | Fracture naphtha 
 Test 5 | Lustre Test 24 | Solubility in other solvents 
 Test 6 | Streak on porcelain UE eane cee Mn 
 Test 7 | Specific gravity Chemical testa + 
 Test 8 | Viscosity Test 25 | Wat : " 
 Test 9 | Hardness or consistency Test 96 | 0 prying 
 Test 9dj| Susceptibility factor Tes 9 uv, oe 
 Test 10 | Ductility ont FF ydrogen 
 . Test 28 | Sulphur 
 Test 11 | Tensile strength Test 29 | Ni Hi 
 Test 12 | Adhesiveness Tea es ee 
 est 30 | Oxygen 
 See eas Test 31 | Free carbon in tars 
 Heat tests : Test 32 | Naphthalene in tars x 
 Test 13 | Odour on heating Test 33 | Solid paraffins 
 Test 14 | Subjection to heat Test 34 | Saturated hydrocarbons 
 Test 15 | Fusing point Test 35 | Sulphonation residue 
 Test 16 | Volatile matter Test 36 | Mineral matter 
 Test 17 | Flash point Test 37 | Saponifiable constituents 
 Test 18 | Burning point Test 38 | Asphaltic constituents 
 Test 19 | Fixed carbon Test 39 | Unsaponifiable matter 
 Test 20 | Distillation test Test 40 | Glycerol 
 Test 41 | Diazo reaction 
 Test 42 | Anthraquinone reaction 
 Test 43 | Liebermann-Storch 
 reaction 
 Test 44 | Iodine number 
 
 
 
 Test 1.—This test calls for no comment, though it is of some 
 use as a means of identification. 
 Test 2.—Homogeneity of the Material to the unaided Eye 
 
 at a temperature of 77° F., or when surveyed under the microscope 
 or when melted, are aids to establishing the identity of the material 
 under examination, and serve to show the presence or absence of 
 mineral matter and free carbon. 
 
 Test 3.—Appearance of Surface Aged one Week. A small 
 quantity of the bituminous material melted at the lowest possible 
 temperature is, after examination of its surface, covered for a 
 week, to protect it from dust, and then re-examined. If bright 
 and lustrous it will indicate perfect amalgamation of constituents 
 and absence of oily and undissolved constituents—a lustreless 
 surface indicates the contrary. 
 
Methods of Testing Bituminous Materials and Pitches 85 
 
 Test 4.—Fracture may be conchoidal (rounded and curved like 
 a shell), or hackly (irregular and rough), and only hard and brittle 
 substances yield to this test. 
 
 Test 5.—Lustre serves as a means of identification—it gives 
 indications of the presence or absence of waxy, greasy constituents. 
 
 Test 6.—Streak on Porcelain. This represents the colour of the 
 powder left behind on drawing a piece of the bituminous material 
 across the surface of unglazed porcelain, and the test serves to 
 indicate the use of the material with coloured pigments. 
 
 Test 7.—Specific Gravity. This test serves as a means of 
 identification and of figuring the weight of a given volume of the 
 material under test. The test is ascertained by the usual hydro- 
 meter, Westphal balance and specific gravity bottle methods, the 
 exact instrument to be used with a given material being conditioned 
 by its nature and consistency. In this country the standard 
 temperature is 15-5° C. (60° F.) but the A.S.T.M. adopt 77° F. 
 
 Test 8.—Viscosity. This test is of use in the examination of 
 materials for road construction. The Engler, Redwood, Saybolt 
 viscosimeters are used in connection with this test, the main use 
 of which is in the examination of liquid and semi-liquid substances 
 for road purposes. The use of these instruments is fully described 
 by B. Redwood, J. Lewkowitsch 1 and others. 
 
 For testing the viscosity or consistency of semi-solid bituminous 
 materials for road purposes the Float Test (Test 8d) is adopted, 
 and this test is not vitiated by the presence of mineral matter or 
 free carbon. 
 
 The instrument as described by Abraham consists of an 
 aluminium saucer-shaped float and a conical brass collar weighing 
 exactly 50 grams together.’ The brass collar is fitted with melted 
 bituminous material upon placing it against a brass plate, the 
 surface of which has been amalgamated with mercury. After 
 cooling it is levelled, placed in water at 41° F. for 15—30 minutes 
 along with the aluminium float, and then screwed into the float 
 and immediately floated on the surface of water warmed to a desired 
 temperature, with the brass collar downward. Very soft materials 
 are tested at 32° F. and hard bituminous substances at 122° or 
 150° F. As the heat is transmitted through the brass collar into 
 the plug of bituminous material, the latter softens until it is forced 
 upwards and out of the collar by the weight of the instrument. 
 The time elapsing between the placing of the float on the surface 
 of the water, and when the water breaks through the plug, is taken 
 as a measure of the viscosity of the material under test. 
 
86 Blacks and Pitches 
 
 Test 9.—Hardness or Consistency. This is largely a test em- 
 ployed in connection with road-making and pavement bituminous 
 materials, and detailed reference to these tests is out of place in 
 the present volume. The familiar Moh’s Hardness Scale is used 
 to some extent, but the Needle Penetrometer % % °4 measures 
 the “‘ Penetration, which is defined as the consistency of a bituminous 
 material, expressed as the distance (usually in hundredths of 1 cm.), 
 that a standard needle vertically penetrates a sample of the material 
 under known conditions of loading (usually 100 grams), time (usually 
 5 seconds) and temperature (usually 77° F.).” A full description 
 of this apparatus, together with an allied one, the Consistometer, is 
 given by Abraham. The Susceptibility Factor (Test 9d) is a 
 numerical expression representing the susceptibility of a bituminous 
 substance to temperature changes. It is calculated from the 
 consistometer hardness and fusing point (K. and 8.) thus: 
 
 Rane cnehiife (Hardness at 32° F.) — (Hardness at 115°) 
 Fusing Point (K. and 8.) 
 
 and is obviously purely an empirical relationship. Usually this 
 
 factor is under 40 for blown petroleum asphalts and fatty acid 
 
 pitches, between 40 and 60 for residual asphalts, and over 60 for tar 
 
 pitches and asphaltites. 
 
 Tests 10, 11, 12.—Ductility, Tensile Strength and Adhesiveness 
 have the physical significance ordinarily attached to these terms, 
 and the tests are mainly of interest in testing road-making bituminous 
 materials. 
 
 
 
 x 100, 
 
 Heat Fests. 
 
 Test 13.—Odour on Heating. Most of the manufactured 
 residual pitches may be recognised by characteristic odours emitted 
 on heating. 
 
 Test 14.—Subjection to Heat. A study of behaviour on melting 
 and heating in a flame is often a valuable guide to identification. 
 Many bituminous materials, especially those of low susceptibility 
 factor, melt sluggishly and have an intermediate pasty stage before 
 reaching complete liquidity; noticeably is this the case with 
 blown petroleum asphalts and many fatty acid pitches. ; 
 
 fest 15.—Fusing or Melting Point. The determination of this 
 point raises much controversy from the fact that in strict scientific 
 parlance the term is somewhat of a misnomer when applied to the 
 complex mixture of fatty acids, hydrocarbons, asphaltic, resinous 
 and other compounds which may constitute a bituminous material ; 
 
Methods of Testing Bituminous Materials and Pitches 87 
 
 such a substance cannot have a definite melting point, but on 
 heating it passes more or less gradually from hardness through all 
 stages of plasticity to complete liquidity, and the actual tempera- 
 ture recorded as the m. p. or f. p. is that at which the material is 
 sufficiently soft to flow. 
 
 A somewhat elaborate method has been devised by G. Kramer 
 and C. Sarnow °° (K. and S. method), and modified and elaborated 
 by H. Abraham. A method called the Cube Method (Test 15c) 
 has been applied to tar-pitches,®°* and a modification of this, due 
 to W. Mansbridge,*’ is preferred for all ordinary purposes by the 
 present author and is carried out as follows. The material to be 
 tested is attached to the bulb of a thermometer, by slightly soften- 
 ing until it adheres, about 6 grams of the pitch or bituminous 
 material, which should cover one-third of the bulb being used. 
 The thermometer is then arranged in a boiling tube (1 in. by 7 ins.), 
 which is fitted into a glass enclosure itself immersed in a small 
 oil-bath, which latter is heated over a small Bunsen flame to give 
 a temperature rise of 2° C. per minute. The thermometer passes 
 through a cork, which closes the tube and is so supported that 
 the bottom of the bulb is 14 ins. from the bottom of. the tube. 
 The temperature at which the bituminous material has softened 
 sufficiently to fall to the bottom of the tube is recorded as the 
 m. p. of the material. — 
 
 Test 16.—Volatile Matter. This serves to identify various 
 bituminous materials. The A.S.T.M. recommends to heat at 325° F. 
 50 grams of water-free substance in a flat-bottomed dish 55 min. 
 by 35 mm. for 5 hours in a previously heated oven.°® 
 
 Test 17.—Flash Point. The value of this test is mainly as 
 a criterion of fire risk. The Pensky—Martens Closed Tester is one 
 of the most generally favoured types of tester in this country. 
 Its use is admirably described in any of the standard volumes on 
 technical chemical analysis, and particularly by Redwood. 
 
 Test 18.—Burning Point. This test is supplementary to. the 
 previous one. The cover of the flash-point tester is removed and 
 the heating and exposure to the test-flame are continued until the 
 vapours ignite and continue to burn. 
 
 _ Test 19.—Fixed Carbon. This test is usually of value with 
 natural asphaltine products, and is carried out as follows: % place 
 1 gram of the material in a platinum crucible of 20—30 grams 
 weight having a tightly-fitting cover, and heat for exactly 
 7 minutes by means of a Bunsen flame 20 cm. high, the mouth 
 of the burner being 6—8 cm. below the bottom of the crucible. 
 
88 Blacks and Pitches 
 
 Cool and weigh. Remove the cover of the crucible and ignite 
 over a full Bunsen flame until only ash remains. The weight 
 of the first residue less the weight of ash gives the weight of wane 
 carbon, which should be calculated to a percentage. 
 
 Test 20.—Distillation Test. As this is generally a test applied 
 to tars, and particularly in connection with road work, the reader 
 is referred to any of the well-known works on tar or petroleum 
 distillation. 
 
 Test 21.—Solubility in Carbon Disulphide. This is often a basis 
 of purchase of bituminous material. The bituminous material 
 should be freed from moisture and 1—2 grams weighed into a 
 150 c.c. Erlenmeyer flask and agitated with 100 c.c. of carbon 
 disulphide. Filtration removes the insoluble matter. The exact 
 procedure to be adopted is outlined in any of the standard works 
 on analysis. The insoluble matter remaining includes both the 
 non-mineral matter insoluble in carbon disulphide (Test 21b) and 
 the mineral matter (21c). The former is determined by ignition 
 in a Gooch crucible, and the residue represents the mineral matter. 
 
 Test 22.—Carbenes—the bituminous substances soluble in carbon 
 disulphide, but insoluble in carbon tetrachloride.1 Carbenes 1 are 
 found in tar and pitches and in certain hard asphalts and asphaltites, 
 but should not occur in petroleum asphalts to an extent in excess 
 of 05%. The procedure is as in Test 21, replacing the carbon 
 disulphide by carbon tetrachloride. 
 
 Test 23.—Solubility in 88° Petroleum Naphtha. The method 
 is performed in the same manner as for determining the portion 
 soluble in carbon disulphide, 88° petroleum naphtha being substituted 
 for the latter. 
 
 Generally it happens that the harder the bituminous product 
 the smaller the percentage that will dissolve in 88° naphtha, and 
 this soluble portion is termed “ petrolenes”’ (also “ malthenes ’’), 
 whilst the non-mineral part insoluble in 88° naphtha is termed 
 ‘* asphaltenes.” 
 
 Test 24.—This calls for no comment—circumstances will decide 
 the solvent to be used and the condition of extraction. 
 
 Chemical Tests. 
 
 Test 25.—Water. The test is mainly used for the purpose of 
 dehydrating the material prior to further examination. Its detailed 
 description will be found in standard volumes on analysis and on 
 tar distillation. ps 
 
 Tests 26, 27, 28, 29, 30.—Carbon and hydrogen are estimated 
 by combustion, sulphur by ignition of the material in a Berthelot 
 
Methods of Testing Bituminous Materials and Pitches 89 
 
 type of bomb calorimeter, nitrogen by the Kjeldahl—Gunning 1 
 method, and oxygen by difference according to the procedure 
 described in any of the well-known works on organic chemical 
 analysis. 
 
 Test 31—Free Carbon in Tars. This is an adaptation of 
 Test 24 suitable for tars and pitches containing free carbon; hot 
 benzol-toluol is the most satisfactory solvent and thorough extrac- 
 tion is necessary. A special apparatus has been devised by H. J. 
 Cary-Curr.18 
 
 Test 32.—Naphthalene in Tars. The method adopted is that 
 given in any of the well-known volumes on coal tar. 
 
 Tests 33, 34, 35 are of lesser importance generally, and as they 
 _ are mainly for the purpose of comparison, they need not be described 
 here, but the reader is referred to C. Richardson. 
 
 Test 36.—Mineral Matter. A detailed examination of this, the 
 amount uncombined, the amount combined with non-mineral 
 constituents, the chemical analysis and microscopic examination 
 of the mineral matter are often of importance in connection with 
 the examination of native asphalts. 
 
 Test 37.—Saponifiable Constituents. In this connection it is 
 often important to determine in fatty acid pitches, wood tar pitch 
 and rosin pitch the amounts of free fatty acids, lactones and an- 
 hydrides, as well as the saponification values. An estimation of 
 fatty and resin acids is also desirable. The usual standard technique 
 described in any of the well-known works on oils and fats is adopted, 
 though it will be found convenient in many cases to use light petro- 
 leum spirit as the solvent. For saponification values, the proposal 
 of Marcusson 1° is to be recommended thus: 5 grams of the pitch 
 or other material in 25 c.c. of pure benzol are refluxed for 1 hour 
 with 25 c.c. of normal alcoholic caustic potash solution, and after 
 cooling 200 c.c. of neutralised 96% alcohol are added, and the 
 mixture is titrated with semi-normal hydrochloric acid solution, 
 using as indicators together 3 c.c. of 1% alcoholic phenol phthalein 
 solution and 3 c.c. of 1% alcoholic alkali blue solution, the colour 
 change being from brownish-red to a distinct blue. 
 
 Test 38,—Asphaltic Constituents. J. Marcusson 1° has outlined 
 methods for distinguishing between native and petroleum asphalts, 
 and in the detailed scheme of analysis proposed he determines free 
 asphaltous acids, anhydrides, asphaltenes, asphaltic resins and 
 oily constituents. 
 
 Test 39.—Unsaponifiable and Saponifiable Matters. This test 
 is of considerable value as a means of identification and as a criterion 
 of quality. The customary methods are applicable after the 
 
90 Blacks and Pitches 
 
 bituminous material has first been freed from insoluble constituents 
 by refluxing with benzol. 
 
 Test 40.—Glycerol. This test is of special importance in the 
 examination of bituminous paints, japans, etc., as glycerol indicates 
 the presence of triglycerides, which may be present in stearine 
 pitches. The standard method?’ is adopted after the glycerine 
 has been obtained by prior saponification. 
 
 Test 41.—Diazo Reaction. This enables phenols to be detected, 
 and is a means of identifying most of the tar pitches. The particular 
 adaptation to be used is that due to E. Graefe.1° 
 
 Test 42.—The Anthraquinone Reaction for detecting anthracene 
 in tar products and 
 
 Test 43.—Liebermann-Storch Reaction, which serves as @ 
 qualitative test for detecting rosin, rosin oil, or cholesterol is the 
 well-known test as described in any standard work on oils and 
 fats. 
 
 Test 44.—Iodine Value. According to Pickering 1° and others, 
 this determination is not usually possible, owing to lack of a suit- 
 able solvent, but the present author has obtained good results for a 
 great variety of fatty acid pitches. About 0-1 gram of the material 
 is dissolved in 20 c.c. of cold carbon tetrachloride, and this operation 
 may require up to 2 hours. The operation is then proceeded with 
 exactly as for a fatty oil by the method of Wijs. Though the 
 solution is usually very dark, the colour change at the end of the 
 titration is quite definite and unmistakable. , 
 
 REFERENCES. 
 
 89 Journ. Inst. Petroleum Technologists, 8, No. 34, Dec. 1922. % * Specific 
 Gravity: Its Determination for Tars, Oils and Pitches,” by J. M. Weiss, 
 J. Ind. Eng. Chem., 1915, 7, 21. 1 “‘ Technology and Analysis of Oils, 
 Fats, and Waxes,” London, 1923. 2 ‘Standard Test for Penetration of 
 Bituminous Materials,” American Soc. for Testing Materials, 1916, p. 530. 
 93 “* Improved Instruments for the Physical Testing of Bituminous Materials,” 
 by H. Abraham, Proc. Amer. Soc. Testing Materials, 1911, 11, 673. «* “The 
 Testing of Bitumens for Paving Purposes,” by A. W. Dow, abid., 1903, 3, 
 352. %5 Chem. Ind., 1903, 26, 55. °* ‘*‘ Methods for Testing Coal Tars and 
 Refined Tars, Oils and Pitches Derived Therefrom,” by 8. R. Church, J. Ind. 
 Eng. Chem., 1911, 8, 228; 1913, 5, 195. ®? J. Soc. Chem. Ind., 1918, 87, 
 pt PR (Serial D6 16) ‘Amer. Soc. for Testing Materials, 1916, p. 533. 
 99 J. Amer. Chem. Soc., 1899, 21, 1116. 1% Clifford Richardson and C. N. 
 Forrest, J. Soc. Chem. Ind., 1905, 24, 310. 191 ‘*‘ Studies on the Carbenes,”’ 
 by K. if Mackenzie, J. Ind. Eng. Chem., 1910, 2,124. 192 ** Standard Methods 
 for Laboratory Sampling and Analysis of Coal ” (D 22-16), American Soc. 
 for Testing Materials, 1916, p. 570. 1° J. Ind. Eng. Chem., 1912, 4, 535. 
 104 “* The Modern Asphalt Pavement, ”” 2nd ed., 1908, pp. 544, BBS. 105 Zeit, 
 angew. Chem., 1911, 24, 1297, 198 ‘Tbid., 1916, 29, 346. 107 « Analysis of 
 Crude Glycerine,” by the International Standard Methods, J. Soc. Chem. Ind., 
 1911, 30, 556. 19° Chem. Zeit., 1906, 30, 298. 1° ‘* Commercial Analysis 
 of Oils, Fats and their Commercial Products,” G. F. Pickering, 1917. 
 
CHAPTER XII 
 NATIVE ASPHALTS 
 
 Origin and Relationship to other Naturally Occurring Bituminous Bodies— 
 The Bermudez and Trinidad Pitch Lakes—Composition of Natural 
 Asphalts. 
 
 In considering the origin of deposits of bitumens and pyrobitumens 
 geological considerations are of prime importance, though within 
 the compass of this chapter it is impossible to make more than a 
 passing reference to the subject. Bitumens and pyrobitumens, 
 in all but a few cases, are found in sedimentary deposits of sand, 
 sandstone, limestone and sometimes in shale and clay—only very 
 rarely in igneous rocks. 
 
 _ Bitumens and pyrobitumens are found in nature in the following 
 ways 8 ;:— 
 
 1. Overflows : 
 
 (a) Springs—source of petroleum and liquid forms of asphalt. 
 
 (b) Lakes—some of largest deposits of asphalt found in 
 this way. 
 
 (c) Seepages—these occur in the case of petroleum and 
 liquid forms of asphalt, usually cliffs and mountain sides 
 bearing impregnated rock. 
 
 2. Impregnated Bike. 
 
 (a) Subterranean pools or reservoirs—all the large eee 
 of petroleum occur in this way. 
 
 (b) Horizontal rock Peed oor and semi-liquid asphalts 
 
 (c) Vertical rock strata occur in this way. 
 
 3. Filling Veins: 
 (a) Caused by vertical cleav-\ The harder asphalts, asphalt- 
 
 age ; ites and asphaltic pyro- 
 (b) Cireed by peraening : bitumens are usually found 
 (c) Caused by sliding ; in fissures as a result of 
 (d) Formed by. sedimenta- one or other of these opera- 
 
 Rene . y i . J tions. 
 
 Discussion as to the origin of bitumens and related substances 
 has generally centred itself on the origin of petroleum, this being 
 
 considered the parent substance. Amongst the theories advanced 
 91 
 
92 Blacks and Pitches 
 
 to account for the origin of petroleum may be cited the one that 
 free metallic elements at high temperatures in the interior of the 
 earth react to produce metallic carbides, which in contact with 
 water produce acetylenes, and these, in turn, by appropriate 
 condensations, give rise to petroleum. W. Ramsay 4 111 has 
 commented on the almost universal occurrence of nickel in the 
 ash from petroleums, and concludes that the catalytic reduction of 
 carbon monoxide or carbon dioxide may account for deposits of 
 petroleum. 
 
 Various organic theories have been advanced purporting to 
 explain the origin of petroleum from decaying vegetable matter, 
 deposits of sea-weeds, etc., and in like manner petroleum and 
 asphalt are considered as possibly derived from accumulations 
 of animal matter and fish, which in time have decomposed into 
 hydrocarbons. In this connection the work of 8. Kawai and 
 S. Kobayashi !!* on a petroleum-like hydrocarbon derived by heating 
 shark liver oil in contact with dry clay under pressure is interesting. 
 K. H. C. Craig 11° has ably summarised the most important of the 
 recent investigations bearing on this subject. 
 
 Notwithstanding the conflicting views as to the origin.of petro- 
 leum, there is substantial agreement that petroleum, once formed, 
 is gradually converted into other types of bitumens and pyro- 
 bitumens, the cumulative influences of time, heat and pressure 
 being important desiderata. 
 
 The view currently held is that advanced by Clifford Richard- 
 son 114115 after a study of the Trinidad asphalt deposit. Here it 
 is concluded that an asphaltic petroleum existing at a considerable 
 depth is converted into asphalt as a result of surface action in 
 which a thorough emulsification with colloidal clay, sand and 
 water is brought about by the action of natural gas acting under 
 high pressure. During this metamorphosis hydrogen is supposedly 
 eliminated, the hydrocarbons being enriched in carbon thereby, 
 and becoming structurally more complex. In turn harder asphalts, 
 asphaltites and asphaltic pyrobitumens may be formed in a 
 favourable environment. 
 
 According to Peckham ™* in a review of the chemistry and 
 technology of Californian bitumen and asphalt since 1865, the 
 polymerisation of petroleum and the rapidity of its conversion 
 into asphalt are due largely to the content of unstable compounds 
 of nitrogen and sulphur in the petroleum. 
 
 Tentatively one may consider the following series of meta- 
 morphoses : 
 
Native Asphalis 93 
 
 Petroleum 
 Non-asphaltic Petroleum Mixed-base and Asphaltic 
 Petroleums 
 Mineral Waxes Asphalts 
 | | 
 
 Pure and Fairly Impure 
 
 a (Rock Asphalts) 
 Asphaltites (Impure Asphaltites) 
 Asphaltic Shales, Asphaltic 
 Pyrobitumens Pyrobitumens 
 
 The non-asphaltic pyrobitumens—the lignites, coal shales, 
 - bituminous coals and anthracite, are outside the scope of our survey 
 and need not be considered therefore. 
 
 We are now in a position briefly to review the more important 
 native asphalts, commencing with those deposits containing less 
 than 10% of mineral matter, and these we may term : 
 
 The Pure Native Asphalts—These are found in various parts 
 of the United States, notably in Utah and California, the deposit in 
 the latter State averaging 85°% asphalt, 10% mineral matter and 
 5% moisture and natural gas. Deposits occur also in Mexico and 
 Cuba, but the most important one is that of Bermudez in Venezuela, 
 the so-called Bermudez Pitch Lake, on the western side of the 
 Gulf of Paria and opposite the Island of Trinidad. The asphalt 
 lake extends over 900 acres in swampy land and averages 4 ft. in 
 depth. Where the asphalt exudes from the springs it is quite 
 soft, but the surface of the deposit hardens slowly on exposure 
 and at the edge of the lake the asphalt is hard and brittle. 
 
 According to Richardson 1 the dried crude Bermudez asphalt 
 has the following characteristics : 
 
 (Test 1) UIE DY) TASB? ces ccdent ta conacdtdensueeeoaws Black 
 
 (Test 4) CRUE ie in Aeiinna's pape xandabavns vogne's nck gie Conchoidal 
 (Test 5) Ne ica hn bss diese ok Whads sans RVbw ces dy hana Bright 
 (Test 7) Specific gravity at 77°F. .....cecsscseeeee 1-005—1-075 
 (Test 15d) ‘Temperature at which it flows ............ 135—188° F. 
 (Test 16) Volatile at 400° F. in 7 hrs. (dried 
 
 SEE Doc vo wer ssaurelnetusancswotnraevs renee 5:81—16-05% 
 (Test 21a) Soluble in carbon disulphide ............ 90—98% 
 (Test 216) Non-mineral matter insoluble ......... 0:62—6:45% 
 (Test 21c) Free mineral matter — ........cccscccccsccocee 0-50—3:-65% 
 
 The water present with this asphalt is not emulsified with the 
 asphalt, as is the case with the Trinidad deposit to be described 
 later. The amount of water varies from 10 to 40%. For a full 
 
94 Blacks and Pitches 
 
 description of the refined Bermudez asphalt the reader must consult 
 Bardwell.11? 118 
 
 Other similar deposits are the La Brea deposit in the delta of 
 the River Orinoco and small deposits in France, Greece, Eastern 
 Siberia and the Philippine Islands. 
 
 Native Asphalts associated with Mineral Matter.—Deposits are 
 found in Kentucky, composed of sand and sandstones with 4—12% 
 of asphalt, whilst in the State of Oklahoma are some of the richest 
 asphalt deposits in the U.S.A. Here the deposits are found in 
 both liquid and solid forms, and most of what is mined is used for 
 paving purposes. The crude rock is-boiled with water, the impure 
 asphalt rising to the surface and the sand waste settling to the 
 bottom. 
 
 Other deposits occur in Texas, Utah and California, at Alberta 
 in Canada, in Mexico and Cuba. The largest deposit in the world, 
 however, is that known as the “ Trinidad Asphalt Lake,” near the 
 village of La Brea in Trinidad. This deposit covers an area of 
 115 acres to an average (estimated) depth of 150 ft. in the centre, 
 where it is undoubtedly fed by gradual seepage from below, as 
 the level of the lake has dropped only very slightly in spite of the 
 removal of vast quantities of the asphalt for use in pavement 
 construction. 
 
 The crude asphalt is an emulsion of bituminous matter, water 
 and finely divided mineral matter, and is very constant in com- 
 position. There is naturally some slight change in character, as 
 the asphalt gradually flows from the centre of the lake, where it 
 is softest, to the edges, where it becomes harder. P. Carmody 1° 
 gives the following data : 
 
 Other 
 Water. Ash. Bitumen. organic © 
 
 matter. 
 
 SOLS os. 29-04% 24:1% 45:6% 1-24% 
 Hard ... 21:-4—27-4% 27-4—29-:7% 40-2—42-0% 4:-4—5:0% 
 
 Samples, after pulverising and drying at ordinary temperatures, 
 show about 55% of bituminous matter soluble in carbon disulphide, 
 and about 35% of mineral matter, the balance being water of 
 hydration, bituminous matter adsorbed by the clay, and thus 
 rendered insoluble in carbon disulphide. 
 
 The bituminous matter of the “ lake asphalt ” is a true asphalt, 
 as distinct from the asphaltites and pyrobitumens. The crude 
 
Native Asphalts 95 
 
 asphalt differs only from a residual asphalt made by the distillation 
 of a crude oil in respect to its large content of mineral matter 
 and relatively high content of sulphur, 2—10%, usually in excess 
 of 4%. | 
 
 From one edge of the lake there is a gradual steady movement 
 of asphalt towards the sea. The asphalt from this flowing sheet 
 is locally known as “land asphalt,” and is not so uniform in com- 
 position and differs somewhat from the “lake asphalt.’’ Carmody 
 (loc. cit.) gives the following examples : 
 
 Soft lake | Hardlake| Land Asphalt 
 
 from 
 asphalt. asphalt. asphalt. need 
 % 70 % % 
 
 Volatile matter .2..6..60...66 54-5 3°3 47-7 33°7 
 
 Fixed carbon .......... oS Se 9-6 10:3 9-8 8:0 
 
 ek ok oa Ven cnsarne 5:7 5-2 4°8 4:2 
 
 ASpHaltenes .....0.....s0ccee. 14-7 16-7 10-4 7-9 
 Total organic to 100 parts 
 
 EROPDATIG: acc see scs> oss. 207°6 180-7 170-1 79-7 
 
 The crude asphalt is refined by heating to about 160° C. to 
 remove water, mechanical impurities being at the same time 
 skimmed off or settled out. : 
 
 The refined asphalt, the so-called Trinidad épuré, has the 
 following properties : 
 
 BIOCHIO STAVIGY BE ZOO. ....0ssnccserersvssesectencecaece . About 1-40 
 Conchoidal fracture and dull lustre. 
 Penetration (Dow) at 25° ©. 2... ...ccvccesevennecvocsenes About 7 
 IRE CLOW OG 2 On a snugncsshensosnnecarancnensens PCR: 
 MRNA MENTE TS, GS, O5-) os nis vinwsinuytnnees seineseusentpnans ORT: veg BP 
 Bituminous matter, soluble in carbon disulphide ... Frigid ty 
 Ec hnaipne vs show's gnagestsrasssttaaauensevearenr’ WE 1. by” 
 Melting point of the pure bituminous matter, free 
 etre AMOI) INALGOL OSS ev cscccescescvescstcossesestes 3» Ob" G; 
 C. 80—82% 
 ae Oo 
 Ultimate analysis of the bituminous material ...... ‘a eck. To 
 
 N. about 0:8% 
 Solubility of the pure bituminous matter upon extraction cold by: 
 
 Acetone . ; : : ey 3 ar hy 
 Benzol . ; , , : 999% 
 Chloroform . ‘ , . 934% 
 Ethylether . : : . 689% 
 
 Native asphalts of lesser importance occur also in France, 
 Switzerland, Germany, Austria, Italy, Spain, Russia, Syria, Iraq, 
 Algeria and deposits of bituminous marl in Ismid, Asia Minor. 
 
96 Blacks and Pitches 
 
 Comparatively recently further light has been thrown on the 
 chemical composition of the natural asphalts by the researches 
 of Marcusson,!?! 122 and he subdivides these bodies into four main 
 classes : 
 
 1. Oily substances, in the main saturated and unsaturated 
 hydrocarbons. 
 
 2. Petroleum resins, or “ Petrolenes,’? which form the first 
 stage of conversion of petroleum hydrocarbons into asphaltenes. 
 They are brownish-black masses soluble in petroleum spirit, 
 chloroform and carbon disulphide. 
 
 3. “‘ Asphaltenes,”’ formed by the action of oxygen or sulphur 
 on the resins, or by intramolecular change in these. The 
 bodies are completely soluble in carbon disulphide, benzol 
 and. chloroform, and contain 7—13% sulphur. These and 
 the parent resins appear to be saturated polynuclear compounds 
 containing oxygen or sulphur. 
 
 4. Asphaltogenic acids, and their anhydrides—tar-like or 
 resinous masses soluble in chloroform and ethyl alcohol. 
 
 The following table is instructive : 
 
 TABLE XX. 
 
 Marcusson’s Subdivision of Asphalts. 
 
 
 
 Free +] 
 eaphatt- | 2000" | Asphaled etal a 
 ORETIE drides. enes. | resins. | stance. 
 acids. 
 Bitumen from Trinidad 3 va gf % % 
 STONE 5 oss ebnos es 6-4 3:5 37-0 23-0 31-0 
 Bermudez asphalt ...... 3-9 2:0 35:3 14-4 39-6 
 
 The “petrolenes”’ of Trinidad asphalt are extremely sticky 
 and of cement-like nature, and not merely oily, and they (the 
 petrolenes) impart to the asphalt its cement-like property. The 
 ““ asphaltenes ’’ impart cohesiveness as distinguished from adhesive- 
 ness, and supply body and stability to the binding material. 
 
 REFERENCES. 
 
 110 J. Soc. Chem. Ind., 1923, 2877. 111 J. Inst. Pet. Tech., 1924, 10, 87. 
 112 J, Chem. Ind. Japan, 1923, 26, 1036. 11% J. Inst. Pet. Tech., 1923, 9, 
 344. 114 J, Ind. Eng. Chem., 1916, 8, 3 and 493. 115 Met. Chem. Eng., 
 1917, 16, 3. 118 Journ. Franklin Institute, 146, [1], 45. 117 118 J. Ind. Eng. 
 Chem., 1913, 5, 973; 1914, 6, 865. 119 J. Inst. Pet. Tech., 1921, 7, No. 28. 
 120 Petroleum, 1923, 19, 576. 121,122 Zeit. angew. Chem., 1916, 29, 346, 349; 
 1918, 81, 113, 119. 
 
Native Asphalts 97 
 
 Bibliography—Native Asphalts. 
 
 “The Nature and Origin of Petroleum and Asphalt,” by Clifford Richard- 
 son, Met. Chem. Hng., 1916, 8, 4. ‘On the Nature and Origin of Asphalt, 
 published by the Barber Asphalt Paving Co., Long Island City, N.Y., 1898. 
 *“The Asphalt and Bituminous Rock Deposits of the United States,” by 
 G. H. Eldridge, U.S. Geological Survey, 1901. ‘‘ Contributions to Economic 
 Geology,’ Bulletin No. 213, U.S. Geological Survey, 1903. F. J. Nellensteyn, 
 Chem. Weekblad, 1924, 21,42; J. Inst. Petr. Tech., 1924, 10, 311. Berginisation 
 of asphalt recently studied by P. Bruylants, Bull. Soc. Chem. Belg. 1923, 
 
 32, 194. H. I. Waterman and F. Korlandt, Rec. Trav. Chim. Pays-Bas, 
 1924, 45, 249. 
 
CHAPTER XIII 
 ASPHALTITES 
 
 Gilsonite, Manjak and Grahamite—Their Occurrence and Characteristics— 
 The Asphaltic Pyrobitumens—Elaterite, Wurtzilite, Albertite, Impsonite. 
 
 ASPHALTITES are naturally occurring asphalt-like substances char- 
 acterised by high melting points (over 250° F.), and Abraham 
 recommends the following means of differentiating their three main 
 classes—gilsonite, glance pitch, and grahamite—one from the other, 
 as follows : 
 
 Specific Fusibility | Fixed 
 Streak. gravity at {| (K. &8.) | carbon. 
 sees A jag ss oe. g 
 
 70 
 Gilsonite or uintaite ......... Brown 1:05—1-10 | 250—350 | 10—20 
 Glance pitch or manjak * ... | Black 1-10—1-15 | 250—350 | 20—30 
 
 Franearni6e-*, 2.. cies anes sa okes Black 1-15—1-20 | 350—600 | 30—35 
 * When substantially free from mineral matter. 
 
 In all three classes the non-mineral constituents are almost com- 
 pletely soluble in carbon disulphide. 
 
 These bitumens are rather narrowly distributed in nature and 
 are considered by Richardson 13> 14 to be the result of metamorphic 
 changes in petroleum under a particular environment. From the 
 softest gilsonite, which will flow slowly on exposure, to the hardest 
 grahamite not melting even at high temperatures, are materials of 
 varying consistency. A hardening in consistency is accompanied 
 by gradual decrease’ in the percentage amount of the material 
 soluble in petroleum spirit or naphtha and an increase in the yield 
 of residual coke. These differences become the more striking when 
 comparison is made with other petroleum derivatives, as shown in 
 the following table due to Richardson : 15 
 
 TaBLeE XXI._ 
 
 Comparison of some Petroleum Derwwatives. 
 
 Specific Sol. in Saturated 
 gravity at naphtha. | hydrocarbon. 
 Cian o % 
 
 
 
 
 
 Petroleum flux (Texas) Tienes: 0:956 
 
 97-5 72:8 
 Petroleum residual pitch ......... 1-089 65-0 33:1 
 Bermudez asphalt ............... 1-082 62-2 24:4 
 Gilsonite (Utah)  .......c.eseeeeees 1-044 47-7 5:5 
 Grahamite (Oklahoma) ......... | 1-171 0-4 0:3 
 
 
 
99 
 
 The relations in composition of gilsonite, grahamite and other . 
 forms of natural bitumen have been tabulated in a paper by 
 Mabery.!26 
 
 Gilsonite.—This is found only in one region extending from the 
 eastern portion of the State of Utah into the western portion of 
 Colorado, and occurs in parallel vertical veins from a fraction of an 
 inch in thickness to a width of 18 ft. The material is removed by 
 a crude mode of mining. 
 
 A sample examined by the present author *4 some time ago had 
 
 Asphaltites 
 
 the following characters : 
 
 MR MUR MRR Daly gs a sy sii cmv is cnssbiacnndadvetcsesiaaesss Jet black 
 NE hina sch n6i4s< sannevaseytersecensexvaane Conchoidal, the 
 sample being 
 very brittle 
 RG incu dn tie a acincds wend ednanas ase ase s uses Very bright 
 ei lenieiaa Stews avssekecsensscoanacessadesws Only 0-75% 
 Solubility in carbon disulphide ................0eeeeeee 99-75% 
 Melting point (drop method) ............ccceeeeeeeeenee 130° C. 
 RPMI TIMACUOD onan ce ssvectcccccsscscessnedsccesveces Nil 
 
 According to Abraham,*° gilsonite is fairly uniform in composition 
 
 and complies with the following characteristics : 
 
 SMT SCONE TEINS 2 css csbacesiscccccsccarctanacenssecews Black 
 
 EM RIALIG civ acu ycctacdsentsccecssccdecccosscecdussies Conchoidal 
 
 Nis cas pn des Avnecnsdvessnccsniechsenen=s4s% = Bright to eich 
 bright 
 
 IE ESTEE Sele kas cescrccesncstginedsesascnsessvicnsavas Brown 
 
 iene). epecihic pravity at 77° Ft ..ccssccecseccascesas 1-05—1-10 
 
 (Test 9a) Hardness on Moh’s scale .........scceeceseeveees 2 
 
 (Test 9b) Hardness, needle penetrometer at 77° F. 0 
 
 (Test 9c) Hardness, consistometer at 115° F. ......... 40—60 
 
 Hardness, consistometer at 77° F.......... 90—120 
 Hardness, consistometer at 32° F............. Too hard for test 
 
 Pieep ud) Biaceptibility factor:  .......scccccscsccsecsoness >100 
 
 (Test 10a) Ductility at 77° F. (Author’s method) ...... 0 
 
 Cee y CPT OT NEALE oo iii. lec csv encecesccoatedines Characteristic 
 
 (Test 14a) Behaviour on melting ........ccccsscccsessseeees Forms a compara- 
 tively thick, vis- 
 cous melt 
 
 (Test 140) Behaviour on heating in flame ...........008. Softens and flows 
 
 (Test 15a) Fusing point(K. & 8. method) ............+6 250—350° F. 
 
 (Test 150) Fusing point (Ball and ring method) ...... 270—370° F. 
 
 (Test 16) Volatile at 325° F. 7 hours (dry substance) Less than 2% 
 Volatile at 400° F. 7 hours cccecssscsessovees Less than 4% 
 Volatile at 500° F. 4 hours ............00000. Less than 5% 
 Ae? PIMC COLDOTE iiss. ines beds) ed veteces dentenes 10—20% 
 (Test 20) Distillation test. 
 Die Oats vas aed Ana da ORV Yee by vaaset Oke kos 9-34% Distillate 
 BN LE i van dice ie dnd bp ewe sae ai 5:35% Distillate 
 Det Cocca cbank senr pendants bade tas ka 12-84% Distillate 
 eee O05 ig cytes bess Sica cudneeeaugeecaaee 28-99% Distillate 
 PMR BU Cl nic, connate Suna dawdeanGhidns Gian Coked 
 (Test 21a) Soluble in carbon disulphide ...............46 Greater than 98% 
 (Test 216) Non-mineral matter insoluble —...........666. 0—19 
 
 SOHOKCHHEH HEHEHE H HHH OHH HHH HEHEHE EEOE 
 
 (Test 21c) Mineral matter 
 
 Trace—1 % 
 
100 Blacks and Pitches 
 
 (Test 22), Carbomes) « \.c...0.. ccpvsnswae aces audbnranwae copay 0—4% 
 (Test 23) Soluble in 88° naphtha  ..........s..seceesseree 40—60% 
 (Test 24) Grams soluble in 100 grams of cold solvent :— 
 Amy] acetate. ..ccipsnsncutnesncaceteeasueietns 86 
 Awav] aloobol<,s.0.- ceataucusy ss cnyn ne eehs weeieee Insoluble 
 AIDY] TIGALO Kuo. en peace ceedeth cr ebiane se eeeee 1 
 Aniine<:’ its). 6. Geka iceaks Cereb eels Insoluble 
 Bonzol ss is vcdss Seah dcouncassetbs aaenneranees 71 
 Carbon disulphide sv. s.+<)se0aa7s saver tuaen ee Soluble in all pro- 
 portions 
 Carbon tetrachloride  Ys...eusteecs cases gana 
 Chloroforna.>\.iscevsseeeessaneaea eke cones onnaenm 54 
 Ethyl] acetaten' $21.4 Wis avy then dn enen em 3 
 Ethyl! alcohol) sie svescs ues seneueeae hexane Insoluble 
 Elthy! thor |: .sviitns os} sogdeanrecesvasteeeaeen eee Soluble in all pro- 
 portions 
 Naéputhia 62° \v.5.i..0-sscseuasteensactspesemeamne 
 Nitsa benrene Vow. .ars euanci ss casucknenpeneeeseiee 9 
 Propyl aloohol <0. aus sane sarees Insoluble 
 ASTOR aio a's inv ssn ocoke acne hang cea Eee 72 
 AUEPODGING 15. hs Cacnksdmevens sasdes eee r eee 60 
 (Peat. 26)" Wagan oivicscscsosanciseackag thausy\aaenieene ee 88—89-5 % 
 (Dest: 27))  STVReORer >. oa. oc. sarsatesnaascessseaenen ae ieee 8-5—10-0 % 
 (Test 28)  Sulphay. gicscccicececnegeysuesace ts oosecekena tee 1-7—2:0 % 
 (Teat 29) Nitrogen cas s<ppusdas sees danepcesuaeiea tate 0:8% 
 (Tost. 30) Oxyoen oo cies 4scpestcantescnnsaaes sebeesgne cena 0—2% 
 (Test 33) Paraffin scale «0.0 i53/. .ceeecetessdctoam ss dagen 0—Trace % 
 (Test 35) Sulphonation residue  .........ssecccececseeeeees 85—95% 
 (Test 37) Saponifiable matter -......i.s..s.scnccsosescesveve Trace 
 (Test 41) . Diaze reaction ~ A ci.iss idevagessaesss scene benecen No 
 (Test 42) Anthraquinone reaction ........sseccecsseoenees No 
 
 Glance Pitch—This resembles gilsonite in external appearance. 
 It always shows a brilliant conchoidal fracture. It occurs in Mexico, 
 Colombia (S. America), Syria and in the West Indies. That occur- 
 ring in Barbados is generally marketed under the name of Barbados 
 ““Manjak ”’ 12” It is claimed that no other native bitumen equals 
 it in respect of its lustre, strength, melting point, intensity of colour 
 and. elasticity. | 
 
 According to Abraham, this ‘‘ manjak”’ contains sulphur 0:7— 
 0:9%, 1 to 2% mineral matter, specific gravity at 77° F. about 
 1-10, fusing point 320—340° F. (K. & S. method), fixed carbon 
 25—30%, and 97—98% of the bitumen is soluble in carbon 
 disulphide. : 
 
 R. H. Emtage 128 also quotes the following analysis for Barbados 
 ‘“ manjak ’—carbon 83-62%, oxygen and nitrogen 2-05%, hydrogen 
 8:29°%, sulphur 0-85%. Water to the extent of 2-499% and ash 
 2:70% are recorded. 
 
 According to Abraham,*° Glance Pitch complies with the following 
 characteristics : 
 (Test 1). ..Colour in mess v)..0....css os «saa eaes eae er Black 
 
 (Test 4) BrAGQre ocicsicccicnsessas kon user emeeaeeepanee ... Conchoidal to 
 hackly 
 
Asphaltites 101 
 
 IE 1k MUI Sy cao dds es ci Chivecy vehVscvsseneseds cancers Bright to fairly 
 7 . bright 
 
 Pee 0) teal On Porcelain ...........ecessensasvenceses Black 
 
 Pee)  pecibepravity ab 77° Foes cc ccsesencendons 1-10—1-15 
 
 (Test 9a) Hardness, Moh’s scale .............ccceeeeceneees 2 
 
 (Test 9b) Hardness, needle penetrometer at 77°F. . 0 
 
 (Test 9c) Hardness, consistometer at 77° F. ..........++ 90—120 
 
 (Test, 92) Susceptibility factor  .........cccsccecccccvssees >100 
 
 Wemernee Iemetatitys At 77? Fe ccssesiec caters es sveceiges: 0 
 
 Set BAICIOMT OF) TNOALING ., 0000s. cersnvectesscestscsscacs Asphaltic 
 
 (Test 14a) Behaviour on melting ............ccscccesesveees Forms a compara- 
 
 tively thick and 
 viscous melt 
 
 (Test 14b) Behaviour on heating in flame ............... Softens and flows 
 (Test 15a) Fusing point (K. & 8. method) ............... 250—350° F. 
 (Test 156) Fusing point (Ball and ring method) ...... 270—375° F. 
 (Test 16) Volatile at 325° F. 7 hours (dry substance) Less than 2% 
 wormere ot 400° Ff. * 7 hours’ .o.s.ccccdsccseces Less than 4% 
 RNS MEME COPION, ooo ncvccccccccencacssevccsssccvevcen 20—30% 
 (Test 21a) Soluble in carbon disulphide .................. Usually greater than 
 ; 95% 
 (Test 216) Non-mineral matter insoluble _............... Less than 1% 
 RPE) UITIONVAL TAGGED... ccc cc cccscccecesteseccosacoaces Less than 5% 
 SEE, MRE eres. oUc du'davicu sos cct'e wens voussecect Less than 1% 
 (Test 23) Soluble in 88° naphtha .............cccseeveees 20—50% 
 RUE TRIES gee Vice cca descVscesccsdebccssincncceosaces 80—85% 
 UE REAPER eos snd chp eeaicnsi¥edeedaeucejescaseds 7—12% 
 EE ENN axis chs sscnceegeqercdcsesccearcynsscns 2—8% 
 (Test 29) Nitrogen and oxygen ......c.ccssccesccssevevens A trace to 2% 
 eR EPI yc spina iless enue Abusbioascevekssceocde 0—trace % 
 (Test 35) Sulphonation residue  .........scceseccesescceees 80—95% 
 (Test 37) Saponifiable matter ...........cccccccessencescccs Trace 
 ee Ey FOACTION eis cisesees cecccccceccsescucesce No 
 (Test 42) Anthraquinone reaction .........sccscceseeeeees No 
 
 Grahamite.—This asphaltite may be very pure or may be 
 associated with as much as 50% of mineral matter. It occurs in 
 West Virginia, Oklahoma, Colorado, Mexico and Cuba. It is found 
 in veins of varying thickness from which it is mined. 
 
 A number of veins of grahamite are mined also in the island of 
 Trinidad, and near San Fernando, on the west coat of the island, 
 occur deposits of the so-called “ manjak.” Its properties are as 
 follows : 
 
 EME PAVIRU EG 20 CO, oa cccuntcrnsanecesserssvsncaves ss About 1:17 
 MRCS ARs OE IS.) sven nsccrdhexsnesancnsengoaneiens 175—225° C. 
 MRL. 5. 50 bc os anvanss ps aioes ads pskaneh wae hee on About 33% 
 ROMS Ti PALOON, CIGUIPHIGS. . 42.00. csercesevacsncsennsey 92—96% 
 ze sete COMPRCRLOSICE. Soiscesevnccheudncs smtee About 54% 
 = petroleum ether 88° Be ......ccscccsscevsees 13—18% 
 
 The largest vein is that worked at the Vistabella mine. The 
 composition of the product throughout this vein is not constant; 
 at the edge the manjak is amorphous or coal-like in character ; 
 at the centre it is lustrous and like gilsonite in appearance. The 
 melting point of this latter type is lower and its solubility in 
 
102 Blacks and Pitches 
 
 petroleum ether,—viz., about 55%—is much greater. The dis- 
 tillation test is as follows : 
 
 Below 160°, sk ntetiege ee alee 0-5% 
 
 £BO—= BOO" CC. iG ccchcancs cst eeeneeaye names 26:5% 
 Above S007-C. chiwcisapiennty cope seees cree 18-:0% 
 Carbonaceous residue —.....ssseessccosences 55:0% 
 
 This “‘manjak” yields on extraction with acetone and sub- 
 sequently with chloroform 12-06% of “ petrolenes’’ and 83-19% 
 of “ asphaltenes ” with 4:75% of insoluble residue.129 
 
 Grahamite, in general, according to Abraham °° complies with the 
 following : 
 
 (Test 1) Colour.in ‘manasa |, 5.2.5 s0n+sarshesideceeotseansee teen Black 
 
 (Test. 4) PraQtare . cis cscacctesessxecberp neh <dees ieee ae Conchoidal to 
 hackly 
 
 (Test -° 8). cL MSt0e y, vives deen cecanteamkh cas antens anaeeeee ieee Very bright to dull 
 
 (Test 6) Streak on porcelain |.......ccwscesses0eunaeeee Black 
 
 (Test 7) Specific gravity at 77° F. :— 
 Pure varieties (containing less than 10% 
 
 mineral MMAGbOr) <<....sacekankess Spann cna 1-15—1-20 
 Impure varieties (containing more than 
 10% mineral matter) ....¢:.sss~sssnnaceee 1-175—1-50 
 (Test 9a) Hardness (Moh’s scale)  ......ssscceeeesceeeeees 2—3 
 (Test 9b) Hardness needle penetrometer at 77° F. ... 0 
 (Test 9c) Hardness, consistometer at 77° F............. Over 150 
 (Test. 9d) Susceptibility factor  ..cceccsesnssenssesaesnemus 100 
 
 (Test 146) Behaviour on heating in flame :— 
 Variety showing a conchoidal fracture 
 
 and‘a black lustre. <..i00.ssuseepseseeunnin Decrepitates 
 violently 
 Variety showing a hackly fracture and a 
 fairly bright to dull lustre. ............ Softens, splits and 
 burns 
 (Test 15a) Fusing point (K. & 8. method) ............... 350—600° F. 
 (Test 15d) Fusing point (Ball and ring method) ...... 370—625° F. 
 (Test 16) Volatile at 500° F. 4 hours .................. Less than 1% 
 (Test 19) ~Pixed €arbon i....00 iiivenss saaktancaxs cet eee 30—55% 
 (Test 21a) Soluble in carbon disulphide ...............0+. 45—100% 
 (Test 216) Non-mineral matter insoluble in carbon 
 disulphide Ty .icisisceehecsdascawees resend Less than 5% 
 (Test 21¢) Mineral matter 1)iinc...)iasu~Jewaiaeek eee Variable (up to 50%) 
 (Test 22). Carb@nee ©. cisasensdsdcanvagy iy peenres enone 0—80% 
 (Test 23) Soluble in 88° petroleum naphtha ............ Trace to 50% 
 (Test 30) Oxygen in non-mineral matter ............... 0—2% 
 (Test.33}° Paraffin 0 issiiiisacee'sscessdcecaseolessdes bs aaneee 0 to trace % 
 (Test 35) Sulphonation residue ...........cceseccenesevees 80—95.% 
 (Test. 37) Saponifiable matter’... .......55-ccs san eesnaeenee Trace 
 (Test-41) °Diazo reaction © 0.0. .c Lien coke ana No 
 (Test 42) Anthraquinone reaction ...........cceessceeeees No 
 
 In general, grahamite is characterised by the following features : 
 
 1. High specific gravity ; 
 
 2. Black streak ; 
 
 3. High fusing point ; 
 
 4. High percentage of fixed carbon; 
 
 5. Solubility of non-mineral matter in carbon disulphide. 
 
Asphaltites 103 
 
 Asphaltic Pyrobitwumens.—These are naturally occurring sub- 
 stances composed of hydrocarbons characterised by their infusibility 
 and comparative freedom from oxygenated substances. The prin- 
 cipal classes, usually containing less than 10% of associated mineral 
 matter, are as follows: 
 
 Specific Fixed 
 Streak. gravity carbon. 
 at 77° F. % 
 3 Light brown 0-90—1-05 2—5 
 yD a re Light brown 1:05—1-07 5—25 
 EATER, 6 oak sh pniuncsscce vase Brown to black 1:07—1-10 25—50 
 PAUP sinc is dnevcrecs. Black 1-10—1-25 50—85 
 
 All these are results of petroleum metamorphosis. 
 
 Hlaterite is found in England, Australia and near L. Balkash 
 and has little beyond scientific interest. It was discovered in 
 Derbyshire in 1673,1°° is moderately soft and elastic, contains 6—7% 
 ash and is slightly soluble in ether. 
 
 Wurtzilite is found only in Utah,1*! occurring there in veins of 
 varying width and length. It is characterised by being sectile and 
 cutting like horn; if bent too far or suddenly it snaps. Its principal 
 tests are quoted by Abraham as follows: . 
 
 ERE as, in alanc hcrccceesd sues aur s¥ecestnss Black 
 OS CTE VICY. A607" Fs... cov ssccseevesercaapens 1-:05—1-07 
 Hardness, consistometer, 77° F. oe... eee eee ees Over 150 
 
 (On heating in a flame it softens and burns quietly, but 
 does not fuse without decomposition.) 
 
 SRD MOER 0 ov anndb pasGeedbrracds svov nave arvve ene 5—25% 
 SPINEL TIUATLOT hn. sssasrorsnsccsesssnvecmercssnaass 0-2—2-5% 
 i oss tno oakn kel paras tsainnner cess ses 5—10% 
 EMMIS RE (Osi syigs Son vias wou dp.) cs 5 08s bocca dahooaga About 80% 
 IN ie Sil ou danipesianicns xs banpagehsnaibile 10—12% 
 Ei abcd cons vatdensnn¥ind 460% sea vunlevardecmied te 46% 
 EE Pn 2 20nd valk wis bb sbiy ws viba cae sonpees vues About 2% 
 
 Albertite occurs in New Brunswick, Nova Scotia, Utah, Tasmania 
 and in West Africa. It is characterised by its infusibility, insolu- 
 bility in carbon disulphide, specific gravity (1:07—1-10 at 77° F.), 
 fixed carbon 25—50°% and small percentage of oxygen (less than 
 3%). At one time this product was utilised to enrich bituminous 
 coal in the manufacture of coal gas. 
 
 Impsonite represents the final stage in the metamorphosis of 
 asphaltites and asphaltic pyrobitumens. It is characterised by its 
 infusibility and insolubility in carbon disulphide and comparatively 
 small percentage of oxygen (less than 5%). 
 
104 Blacks and Pitches 
 
 The most important deposits are found in Oklahoma, Arkansas, 
 Nevada. 
 
 Somewhat allied are the asphaltic pyrobituminous shales and 
 the non-asphaltic pyrobituminous shales, in the latter of which are 
 associated the cannel coals, torbanites and pyropissite. For further 
 information on these latter substances the reader is referred to the 
 publications of Watson Smith,!? Baskerville and Hamor }** and 
 others. 
 
 REFERENCES 
 
 123 “ Gilsonite and Grahamite,’’ by Clifford Richardson, J. Ind. Hng. 
 Chem., 1916, 8, 496. 1%* ‘* Grahamite, a Solid Native Bitumen,”’ by Clifford 
 Richardson, J. Amer. Chem. Soc., 1910, 82, 1032. 125 J. Ind. Hng. Chem., 
 1916, 8, 493. 126 J. Amer. Chem. Soc., 1917, 39, 2015. 127 Oil and Colour 
 Trades Journal, 1919, 56, 2093. 4128 ‘‘ The Mineral Industry during 1908,” 
 17, 71. 1°° Bulletin of Imperial Inst. (Supplement to Board of Trade 
 Journal), 1903, 4, 180. 1° Lister, Phil. Trans., 1673. 131 W. P. Blake, 
 Trans. Amer. Inst. Mining Eng., 1889, 18, 497. 132 J. Soc. Chem. Ind., 
 1909, 28, 398. 183 “‘ American Oil Shales,’ 8th International Congress of 
 Applied Chemistry, 1912, 25, 631. 
 
CHAPTER XIV 
 PETROLEUM ASPHALTS, OR RESIDUAL PITCHES 
 
 Occurrence, World’s Production, and Refining of Petroleum—Characteristics 
 of Residual, Blown and Sulphurised Petroleum Asphalts. 
 
 VeERY closely allied to the native asphalts are the residuals from 
 the distillation of petroleum, not only by reason of similarity in 
 appearance and in chemical composition, but in virtue of similarity 
 of applicability. These petroleum asphalts are jet-black shining 
 solids, often brittle and usually showing a conchoidal fracture, 
 having a low ash content, usually about 0-1%. With the exception 
 of the Mexican residuals, they contain only small amounts of 
 sulphur, so that in these two latter respects they are in marked 
 contrast to the native asphalts. 
 
 Petroleum occurs in different parts of the world, and varies 
 widely in composition. The extent of its production is shown in 
 a table recently prepared by Mr. George Sell, published in a paper on 
 “‘ Crude Oils of the Empire ’”’ 1*4 (see Table XXII, p. 106). 
 
 From the standpoint of this chapter, petroleums may be divided 
 into three groups : 
 
 1. Those bearing a substantial quantity of solid paraffins, 
 usually associated with open chain hydrocarbons. 
 2. Those bearing a substantial proportion of asphaltic bodies, 
 usually associated with cyclic hydrocarbons. 
 3. Those of mixed composition, bearing both solid BeAeng 
 and asphaltic bodies. 
 
 Paraffinoid hydrocarbons predominate in the petroleums produced. 
 in Pennsylvania, West Virginia, Lima (Ohio), Canada and Alaska, 
 and the residues do not yield asphalts on distillation. 
 
 Mixed base petroleums covering both asphalts and paraffins 
 occur in Illinois, Texas, Mexico and Roumania. 
 
 Cyclic hydrocarbons predominate in petroleums produced in the 
 Mexican Gulf field, California, Trinidad, and these fields yield 
 asphaltic petroleums. In the case of the Borneo field, some of the 
 petroleum here is asphaltic, whilst some has a paraffin base. The 
 Baku field gives a petroleum in which the cyclic hydrocarbons of 
 the C,H,, series—the naphthenes—predominate, though the oil is 
 not asphaltic. 
 
 After dehydration crude petroleum is fractionally distilled, the 
 process being intermittent or continuous, and both methods are 
 employed either with or without steam: in the latter case the 
 
 distillation is said to be dry. 
 : 105 
 
106 
 
 Blacks and Pitches 
 
 TABLE XXII. 
 
 World’s Production of Petroleum. 
 
 (In Imperial gallons.) 
 
 
 
 1923. 
 Estimated 
 or based on 
 preliminary 
 
 returns. 
 
 — | ES | | 
 
 United States |15,519,070,000 |16,526,305,000 |19,513,585,000 |25,399,570,000 
 
 Mexico 
 Russia 
 Eastern 
 Archipelago 
 Persia 
 Roumania... 
 Galicia......... 
 POP So cess 
 Japan and 
 Formosa... 
 Argentina ... 
 Venezuela ... 
 France: ..<.. 
 Germany...... 
 SIAL Osan css 
 
 British Empire— 
 India 
 
 Egypt 
 Sarawak ... 
 Canada .... 
 United 
 Kingdom. 
 
 eeveee 
 
 6, 
 
 103,089,600 | 6,460,129,200 | 6,370,000,000 | 5,233,544,000 
 907,500,000 924,000,000 | 1,209,000,000 | 1,344,000,000 
 585,541,500 588,464,400 585,189,000 583,000,000 
 394,703,100 505,660,500 665,081,700 846,487,700 
 263,875,300 301,846,100 354,678,700 391,340,400 
 196,062,200 180,694,400 182,804,200 188,831,000 
 98,582,700 125,000,000 127,000,000 128,000,000 
 93,205,000 91,000,000 90,000,000 88,000,000 
 50,963,600 51,247,500 71,087,400 80,000,000 
 17,360,000 50,000,000 70,000,000 100,000,000 
 13,601,800 13,766,500 19,101,000 17,511,900 
 8,418,700 9,000,000 11,000,000 13,000,000 
 1,360,500 1,317,300 1,300,000 1,300,000 
 293,116,800 305,683,200 298,504,100 298,000,000 
 72,906,000 82,395,600 85,566,300 90,000,000 
 37,281,100 51,376,000 45,000,000 35,000,000 
 35,138,100 49,632,200 100,178,900 135,000,000 
 6,868,800 6,563,900 6,267,400 6,160,000 
 102,100 91,400 32,800 7,500 
 
 ee ee | | | eS 
 
 Total 
 
 Figures in black are estimated. 
 
 ... |24,698,746,900 |26,324,173,200 |29,805,376,500 |34,978,762,500 
 
 For full details as to the operation of petroleum distillation the ~ 
 reader must have recourse to the works of Redwood 1%5 and Camp- 
 
 bell,18° but in bare outline two refining schemes may be quoted, due 
 to A. E. Dunstan and J. Kewley: 1%4 
 
 Topping Scheme. 
 
 Crude oil distillation. 
 
 | 
 Petrol from 
 pre-heater. 
 
 Benzine. 
 
 Crude | ge 
 
 Crude benzine. 
 Redistillation. 
 
 Residue. 
 
 ~- Kerosene. 
 
 Redistillation. 
 | 
 
 Residue 
 
 Residue 
 fuel oil. 
 
Petroleum Asphalts, or Residual Pitches 107 
 Full Refining Scheme. 
 
 Crude oil distillation. 
 
 Petrol from Crude benzine. Once-run Heavy 
 
 pre-heaters. Redistillation. kerosene, residue, 
 pitch or 
 coke. 
 Benzine in Residue. Redistillation. Loss, 
 one or more 
 grades. 
 Kerosene. Intermediate oil. 
 
 Heavy oil and paraffin 
 Redistillation. 
 
 | 
 2nd stage H. O. & P. Residue, 
 In one or two fractions. pitch or 
 Refrigeration. coke. 
 
 5 Loss. 
 
 Paraffin scale. Filtrate. 
 Fractional sweating. Lubricating oil base. 
 Refractionation or concentration. 
 
 
 
 | 
 High ating point Low melting point 
 wax. wax. 
 Decolorisation. 
 Candle manufacture. 
 
 The main refinery products are given in Table X XIII below : 154 
 
 TaBLeE XXIIT 
 Principal Refinery Products from Crude Petroleum. 
 
 Specific Initial and 
 Name. gravity final boiling Remarks. 
 range. points, ° C. 
 Naphtha . 0-728—0-759 95—150 — 
 Gasoline \Benzine eats 0-639—0-780 31—190 ee 
 TROT OMENG. 5 oss sei iscs ices 0-785—0-811 140—310 — 
 PRAMAS chicka Sinu decays ss 0-816—0-855 300—350 —— 
 Ee ren 0-85 —0-96 300 and Not more than 
 upwards 1% of sulphur. 
 Lubricating oil ......... 0-882—0-905 300 and Free from sul- 
 upwards phur and 
 ; asphalt. 
 Residual oil ..........5.:.. 0-928—0:96 — — 
 
 
 
 The residual products obtained in the distillation of petroleums 
 are represented by the following classes, according to Abraham : 
 
108 Blacks and Pitches — 
 
 (a) Residual Oil.—The residue from the dry-distillation of 
 paraffinoid petroleums, the steam or the dry distillation of mixed- 
 base petroleums and the steam distillation of asphalt-bearing 
 petroleum. This residual, termed liquid asphalt, petroleum flux, 
 etc., is liquid or semi-liquid at the ordinary temperature. 
 
 (b) Residual Asphalt,—The residue from steam or dry distillation 
 of mixed base and the steam distillation of asphalt-bearing petro- 
 leums. 
 
 (c) Blown Asphalts.—The products obtained by blowing air 
 through residual oils at high temperature. | 
 
 (d) Sulphurised Asphalt.—A product obtained by heating residual 
 asphalt with sulphur at high temperature. 
 
 (ec) Sludge Asphalt.—The asphalt-like body separated from the 
 acid sludge produced in the refining of petroleum distillates with 
 sulphuric acid. The newer methods of refining petroleum will 
 doubtless eventually eliminate this type of residual. 
 
 (f) Petrolatum or Vaseline. 
 
 The following yields are obtained from a California asphaltic 
 petroleum : 187 
 
 Gasoline (60? BG.) .<issessiedacenuencabeut texcessenes Trace—20% 
 Naphtha (66° 336.) ....0:ss0ssteaesenstqnateeastemeaenes Trace—15% 
 Kerosene (35—42° Bé.) ....cccccccceseccsescccccceece Trace—30% 
 Gas or fuel oil (25—30° Bé.) .........ccccseeeseseees 10—40% 
 Lubricating oil (17-—25° Bé.) — .......scesscccveveee 15—70% 
 Ftesidual asphalg .....cssccesanoncedetseuvenstnaccieenny 20—40% 
 LpDGE \ nninas cup niane cnn tase bouseehdsoeduive humans oat atiaeee 1—4% 
 
 The characteristics of residuals depend on the following factors : 
 
 (a) The nature of the petroleum from which they are derived. 
 
 b) The extent to which the distillation is carried. 
 
 (c) The method of distillation employed and the care with — 
 which the operation is conducted have some bearing on the 
 result also. 
 
 Residual asphalts in general comply with the following charac- 
 teristics given in a table due to Abraham : 
 
 (Test 1) -ColQur $23, 2098 2. o0.5 cx adeaeetccabheis aes Black 
 
 (Test 2) ‘Homogeneity, ....2.cs-egenecttesandesnasnee ee Variable 
 
 fToats 4) PROC ure Sixes vacag cus ecdeanayepaheuken menses ait Conchoidal in case 
 of hard residues 
 
 (Test 6) Streak om porcelain ........cscccsccccesessooes Black 
 
 (Test 7) Specific gravity at 77° BF. ......cscccsseeees 1-00—1-17 
 
 (Test 96) Penetration at 77° FB.  ........cccceescceeeeees 150—O 
 
 (Test 9c) Consistency at 77° Br. ..cccsscsecedeccccoccnes 5—100 
 
 (Test 9d) Susceptibility factor  ...........c.cceceeeeees 40—60 
 
 (Test 11) Tensile strength at 77° F.  .......cceseeeees 0-5—10:0 | 
 
 (Test 15a) Fusing point (K. & 8.) ....... kien ye eae 80—225° F. 
 
 (Teat.17) > Blesh point s (....carcasacendendbiameensaten anes 400—600° F. 
 (Vest 18)" Barnine poine itscs ss ncane eee eens enna 450—700° F. 
 
Petroleum Asphalis, or Residual Pitches 109 
 
 DRE SET AERA CATON Wiviyecs a biinassuacetedeccaresecdee 5—40% 
 (Test 21a) Soluble in carbon disulphide ............... 85—100% 
 DAME BAC) MAITIOTAL INALLOL .. occ cccececsccscsusecesvaccseees 0—1% 
 (Test 23) Solubility in 88° naphtha ................45 25—85% 
 
 Carbon 85—87%, Hydrogen 9—13%, 
 Sulphur trace —10%, Nitrogen trace 
 —1%, Oxygen 0—2-5% 
 Saponifiable constituents  .........seseeeeee 0—2% 
 Some petroleum residual pitches examined by the present author *4 
 
 showed the following characters :— 
 
 Specific 
 
 gravity at | M. p. (° C.). art 
 
 15-5° C, ‘ 
 
 _ Residual pitch from— 
 
 An American petroleum I . 1-045 82—83 0-07 
 9 - $s 9 Roe 1-060 110 0-08 
 A Mexican petroleum ...... 1-001 122 0-12 
 An Asiatic See ae ae 1-107 65—67 | 0-72 
 
 None showed more than a trace of saponifiable matter, and except 
 in the case of the Mexican variety, sulphur was present only in 
 trace. 
 
 According to Marcusson,!%8 petroleum residual asphalts or 
 pitches do not contain asphaltogenic acids, and the proportion. of 
 oily constituents (and their characteristics) depends on the extent 
 of the distillation, but the amount is much greater than in the 
 natural asphalts. The residues from some of the American petro- 
 leums contain notable quantities of aromatic hydrocarbons, such as 
 anthracene, phenanthrene, chrysene and pyrene. Further, these 
 residual asphalts are insoluble in water, acids, alkalies and only 
 slightly soluble in alcohol, though readily soluble in benzol and 
 carbon disulphide. 
 
 Blown Residual Asphalts. 
 
 Air-blown asphalts derived from residual oils derived in turn 
 from asphaltic mixed base or non-asphaltic petroleums have been 
 manufactured for many years since they were first reported upon 
 by Gesner in 1865, and the first commercial scale operation was 
 brought about by F. X. Byerley in 1894.18° Generally, air and 
 steam are blown into the residual oils at 270—300° C. for 10 to 24 
 hours. The advantages of “‘ blowing” over steam distillation are 
 that it is easier to produce an asphalt of a particular grade and of 
 better quality, and, in addition, the asphalt acquires a somewhat 
 rubber-like property. Moreover, the yield of asphaltic residue from 
 “blowing ” is greater than by steam distillation. 
 
110 Blacks and Pitches a 
 
 What the chemical changes are during blowing is uncertain, but 
 D. Holde and S. Weill 44° have examined some of these blown 
 asphalts, and find their saponification values increase with rise of 
 melting point. In general, blown asphalts comply with the follow- 
 ing characteristics : °° 
 
 (Test 1) © Colony im aan} 2S. avh weet dat aen eeeeec ae Black 
 (Test 2a) Homogeneity to the eye at room tempera- 
 PATO: ions sunsare ctubu cas uns haa ene emeeae ies ane Uniform to gritty 
 (Test 2b) Homogeneity under the microscope ......... Uniform to lumpy 
 (Test 3) Appearance surface aged indoors one week Bright to dull and 
 greasy 
 (Test 4) Pragya ss ssccc cas cncadeetohnoswicescees cuae eevee Soft grades do not 
 
 show a fracture, 
 hard grades pre- 
 sent a conchoidal 
 
 fracture 
 
 {Peat 67%. LUstre 24 ane dasevewhian> pacntawhsncne ooeeanraneem Bright to dull 
 
 (Test 6) Streak on porcelain .........6<.)..nscscuutaeasvan Brownish-black to 
 black 
 
 (Teast 7)--Specific gravity at: ITF. ian See 0-90—1-07 
 
 (Test 9c) Consistency at 77° Br. ....ccccccscccccccescencens 2—30 
 
 (Test 9d) Susceptibility factor  ......ccccsscsscscccsecsees 8—40 
 
 (Test 10)  Ductility © o.......Nidac. ivackes divas casket Variable 
 
 (Test Tl} ‘Tensile strength “..n..cisssacsncekectwavarcyeeras Variable 
 
 (Test 15a) Fusing point (K. & 8. method) ............... 80—300° F. 
 
 (Test 156) Fusing point (Ball and ring method) ...... 100—325° F. 
 
 (Test 16) Volatile matter, 500° F.in 4 hours ......... I—12% 
 
 (Test 210) Flags pO © \<sjccresvwedd ses sp varaet tenn gee cee 350—550° F. 
 
 (Test 18). “Burning ‘potint 5 is ccvadekedsdectsaheeeagtn ine gee 400—650° F. 
 
 (Test 19) -Wisced carbon ..$i vcssna oceessdpescamie gi scegsenoceee 5—20% 
 
 (Test 21a) Solubility in carbon disulphide ............... 95—100% 
 
 (Test 216) Non-mineral matter insoluble ............... 0—5% 
 
 (Test-21¢c) Mineral miatter .i).scdesks ies sinsenseey ems 0—3% 
 
 Test22) -Darbenes ..,..+.cassbsatavsstadeesag pakanen er ee 0—10% 
 
 (Test 23) Solubility in 88° naphtha ...................4. 50—90% 
 
 (Test 24) Solubility in other solvents  ...............00. Largely soluble in 
 
 turpentine and 
 benzol, and 
 slightly soluble in 
 
 alcohol and acetone 
 (Test 25) Water «25. ccoscekenerguen ee ni ruca mentee uae ane Absent 
 (Test.28): Sulphur .o5ccsdesscsacnceaees teeth aiecereeaeen Trace —7:5% 
 (Test:30). Oxy Gert» .5..s5.casesecsepuch avai Cask aseseeehtcnreae 2—5% 
 (Test 33). Parefiits 3.0005. crvacsakewes us stiecastecesnctermerneaun 0—10% 
 (Test 34) Saturated hydrocarbons ............scsseseeeees 30—75% 
 (Test 35) Sulphonation residue  ...........cccscceecsceeees 90—100% 
 (Test 37) Saponifiable constituents  .............ceeeeeee Trace —2% 
 (Tost 20) GiyOerol ive akaks een cana ancien aralies poem None 
 (Test 43). Diazo reaction” ...ccccscsasdtsccteanckene saccnaunene No 
 (Test 42) Anthraquinone reaction . ........csceceseereeeees No 
 
 Sulphurised Asphalts. . 
 
 Under the action of heat, sulphur has a sort of condensing action on 
 
 asphalt—analogous to vulcanisation possibly. Abraham represents 
 the process roughly as C,H, + 8 = C,Hon-. + HS. 
 
Petroleum Asphalts, or Residual Pitches 111 
 
 Numerous patents have been effected for sulphurising asphalts, 
 fatty acid pitch, coal-tar pitch, grahamite, etc., but the use of 
 these sulphurised bodies has generally been abandoned. 
 
 Recently, however, H. Burnice 144 has treated residues from 
 Roumanian crude oil with about 7:-5% sulphur, and claims to have 
 produced a particularly good product. 
 
 Sludge Asphalts. 
 
 These are not now produced to the extent that formerly obtained. 
 They are characterised by the following features: intense black 
 streak, high percentage of sulphur, high percentage of oxygen, 
 which distinguishes them from all other forms of asphalt and the 
 _ small amount of paraffin and saturated hydrocarbons they contain. 
 
 Much discussion and investigation have centred on the problem 
 of satisfactory methods for differentiating the various natural and 
 artificial asphalts and bitumens, and one may cite as references the 
 publications of Hutin,!*# Graefe,14* Pailler,444 Marcusson 14° and 
 Richardson.“ The conclusions drawn by the last-named investi- 
 gator are particularly noteworthy, for it is shown that the natural 
 Trinidad and Bermudez asphalts consist largely of unsaturated 
 hydrocarbons, and following in order of increasing percentage of 
 saturated hydrocarbons we have respectively Trinidad residual 
 pitch, Mexican petroleum pitch, Californian petroleum pitch, and 
 Texas petroleum pitch. From this follows the very important con- 
 clusion that the greater the percentage of saturated hydrocarbons 
 in a bitumen the less pronounced are its asphaltic characters. 
 
 K. C. Pailler 147 has pointed out the differences between natural 
 and petroleum residual asphalts based on estimation of the fixed 
 carbon, the acidity of the liquid obtained on careful dry distillation 
 and on the saponification value. 
 
 REFERENCES. 
 
 134 Dunstan and Kewley, Journ. Inst. Pet. Tech., 10, No. 44, July 
 1924. 135 “A Treatise on Petroleum,’’ Sir Boverton Redwood, 4th ed., 
 3 Vols. 1922. 156 ‘‘ Petroleum Refining,’ by Andrew Campbell, 2nd ed., 
 London, 1922. 137 Bulletin No. 32, California State Mining Bureau. 158 Zevt. 
 angew. Chem., 1918, 31, 113,119. 1° U.S. Patents 237,662 and 239,466 of 1881. 
 140 Petroleum, 1923, 19, 541. 141 English Patent 188,354. 14% Caoutchouc 
 et Guttapercha, 1916, 18, 8994. 143 Zeit. angew. Chem., 1916, 29, 21. 444 J. 
 Ind. Eing. Chem., 1914, 6, 286. 145 Zeit. angew. Chem., 1913, 26, 91. 148 J. 
 Ind. Eng. Chem., 1916, 8, 319. 4147 J. Soc. Chem. Ind., 1919, 38, 940a. 
 
 Bibliography—FPetroleum Asphalts. 
 J. M. Weiss, J. Ind. Eng. Chem., 1918, 10, 732 and 817. J. Marcusson, 
 
 Mitt. K. Materialpruf, 1918, 36, 279. ‘‘ Detection of Natural Asphalt and 
 Petroleum Pitch,” F. Schwarz, Chem. Fett. Harz. Ind., 1913, 20, 28. 
 
CHAPTER XV 
 COAL-TAR PITCH AND ALLIED PITCHES 
 
 Residuals in Pyrogenous Distillation—Occurrence, Genesis and Composition 
 of Coal—Destructive Distillation of Coal—Composition, Properties and 
 Uses of Coal Tar—Coke Oven, Producer Gas and Blast Furnace Tars— 
 Distillation and Properties of the Resultant Tar Pitches. 
 
 In this country the best known pitch and that produced in by far 
 the largest amount is the familiar Coal-tar Pitch, and under this 
 heading will be considered the pitches corresponding to the tar 
 recovered as by-products from bituminous coal carbonised or 
 consumed. in f 
 
 1. Illuminating Gas Works. 3. Blast Furnaces. 
 2. Coke Ovens. 4. Gas Producers. 
 
 According to a recent return,148 the quantities of Tar Pitch pro- 
 duced in Great Britain in the years 1922 and 1923 were as follow : 
 
 1922. 1923. 
 From gas and coke-oven works ...... (tons) 490,573 624,641 
 From Other Works cess crntsisscansatesena (tons) 23,663 52,721 
 
 The consideration of the production of the tars themselves is 
 rather outside the scope of the present volume, and the reader is 
 referred to any of the well-known works on Gas Manufacture, etc., 
 for full information. It is not out of place, however, to point out 
 that tars constitute the volatile and oily decomposition products 
 obtained in the pyrogenous treatment of bituminous and other 
 organic substances, such as shale, peat, greases, etc., and the result- 
 ing distillates are usually of liquid consistency, dark brown to black 
 in colour, and have an odour usually characteristic. The synopsis 
 reproduced on p. 113, due to Abraham, indicates the raw materials 
 used and the modes of treatment. 
 
 The temperature to be employed depends much on the materials 
 to be decomposed, but high temperatures result in the formation 
 in the tars (and hence in the resultant pitches) of higher amounts 
 of free carbon, due to greater thermal decomposition (“ cracking ” — 
 or “ pyrolysis ’’), and also lead to the formation of a very large 
 number of hydrocarbons and allied substances in addition. This 
 subject of the pyrogenesis of hydrocarbons has been treated fully 
 by A. E. Dunstan, F. B. Thole and E. L. Lomax,™® and the reader 
 is referred to the survey by those authors of the chemical problems 
 involved. ) 
 
 Coal-tar Pitch is a product of the distillation of coal tar, which 
 in turn is a by-product in the manufacture of illuminating gas from 
 coal, the yield of tar in such manufacture being approximately 4% 
 
 112 
 
Coal-tar Pitch and Allied Pitches 113 
 TABLE XXIV. 
 
 Residuals in Pyrogenous Distillation. 
 
 
 
 Want Partial decomposition. 
 alone ** Cracking ”’ 
 Raw materials used. | (‘‘ Destruc- Limited of oil 
 tive dis- access of vapours. 
 tillation isi air. 
 Bituminous substances : Oil t 
 Petroleum products . — Ww Et OE 
 ater-gas tar 
 EE a ee Peat tar Peat tar -- — 
 DID ivacacss vncvnay sess Lignite tar | Lignite tar — — 
 Pyrobituminous shales | Shale tar Shale tar — — 
 | Gas-works |) Producer- | Blast- 
 Bituminous coals . gas coal furnace mo 
 Coke-oven fe ta 
 Coal tar 
 Other organic materials : 
 9 ROOT ee ee eg Wood tar — oes 
 BRONTE iCrineedc deers cs Bone tar — -- 
 
 
 
 of the weight of coal carbonised. As coal, therefore, is the ultimate 
 parent of coal-tar pitch, it is of interest to know something of the 
 former. Stopes and Wheeler 1°° have defined coal thus: ‘‘ Ordinary 
 coal is a compact stratified mass of mummified plants (which have 
 in part suffered arrested decay to varying degrees of completeness), 
 free from all save a very low percentage of other matter. Veins, 
 partings, etc., which are found in nearly all coal are local impurities 
 and are not part of the coal itself.” 
 
 Coal is found in many parts of the world, by far the largest 
 deposits (chiefly humic or so-called bituminous coal) occurring in 
 the Coal Measures of the carboniferous period. The coal-forming 
 vegetable materials have accumulated in a variety of ways—on 
 land, in sea-water, in fresh-water, and in brackish water. Bone 15! 
 has recently put forward in tentative outline a scheme indicating 
 the possible formation of coal through various stages, commencing 
 with the lignocelluloses, vegetable proteins and resins composing 
 the original vegetable material. 
 
 Researches by leading geologists and botanists indicate that 
 coal has been formed from plants occurring in the following groups : 
 
 Thallophyta (alge and fungi). 
 
 Bryophyta (mosses and liverworts). 
 
 Pteridophyta (ferns, horsetails). 
 
 Gymnosperme (the Araucaries, Cycadaces, Ginkgoaceee). 
 
114 Blacks and Pitches 
 
 Coals vary much in character, and it is found convenient to 
 divide them broadly into the following groups : 1°? 
 
 1. Brown Coals or Lignites. 
 
 Cannel Coals. 
 
 Bogheads or Torbanites. 
 3. Humic or Bituminous Coals. 
 
 4. Anthracite Coals. 
 
 As we are here concerned only with a product derived ultimately 
 from bituminous coals, it is sufficient to confine our attention to 
 coals of this class which are black, of more or less even brightness 
 and which separate into more or less rectangular pieces when broken. 
 
 Various schemes for classification of coal on an analytical basis 
 have been put forward, though none is satisfactory. But Lewes 
 suggested that the coking or non-coking power of coal will depend 
 upon the preponderance in the first case of resinous bodies and 
 hydrocarbons, and in the second case of humus bodies and residuum 
 (carbon). 
 
 The study of the action of solvents on coal has received much 
 attention in recent years, and Clark and Wheeler 1** have come to 
 the conclusion that coal contained two main groups of bodies, 
 ‘““humous ”’ and ‘resinous”’ respectively. Jones and Wheeler 1°° 
 obtained a solid paraffin, chiefly heptacosane (C,,H,,), from a bitu- 
 minous coal. An investigation on the resinic constituents and 
 coking properties of coal has been carried out by W. A. Bone, A. R. 
 Pearson, E. Sinkinson and W. E. Stockings,45* and a number of 
 important results have been recorded. 
 
 It is evident that the coal substance can be divided into two 
 main groups, viz., cellulosic (humic) and resinic, and hydrocarbon 
 bodies (both saturated and unsaturated), and resinous bodies have 
 been isolated, which indicates that these compounds exist in the 
 free state in many types of coal. 
 
 A comprehensive review of the present enews of the com- 
 position, properties and uses of coal-tar pitch is given in a paper 
 by Weiss,1°? who points out that the character of the pitch depends 
 on : 
 
 2. Sapropelic Coals 
 
 (a) The character of the tar distilled. 
 (b) The percentage of total distillate removed. 
 
 But, as is pointed out by Butler,15® the composition of coal tar 
 is so varied, and is dependent on such a variety of factors, that no 
 analysis that is fairly representative can be given. This investi- 
 gator further adds that coal tar varies principally as follows : 
 
 ' 
 
Coal-tar Pitch and Allied Pitches 115 
 
 (1) That containing a preponderance of open chain par- 
 affinoid bodies and giving a lower yield of pitch. 
 
 (2) That characterised by the presence of closed chain 
 aromatic compounds, free carbon and leading to a greater 
 yield of pitch. 
 
 The specific gravity of coal tar varies in practice between 1-070 
 and 1-215, according to temperature of carbonisation and the type 
 of retort used. According to Wright,!** lower specific gravity tars 
 generally result when a low-carbonisation temperature (800° C.) is 
 used, or if the coal be carbonised in vertical retorts, whereas high 
 temperatures (1100° C.) and the employment of horizontal retorts 
 lead to high gravity tars. The point of this is that the lower specific 
 gravity tars are more aliphatic in character, and thus influence the 
 properties of the pitch subsequently produced; such tars arise in the 
 relatively new Del Monte process of distilling coal. 
 
 The extent to which tars vary in their yield of commercial 
 distillates is indicated in the following table, due to E. G. Stewart.159 
 
 TABLE XXV. 
 
 — Commercial Distillates from Gas Works Tar. 
 
 Works using | Works using 
 
 high heats | moderate heats ara on 
 and light and fairly bie! ee 
 charges. heavy charges. hiatal 
 % % % 
 | eee an 2-0 2-0 2-0 
 Be GUID vive cans cyineecsdevess 1-0 6:0 5:6 
 Carbolie and creosote oils 14-0 32-0 41-4 
 Anthracene oil .-............ 5:0 4:0 4-0 
 NS ON RD Og 78-0 56-0 47-0 
 ‘“* Free carbon ”’ in pitch 36-0 17-0 5:5 
 
 Closely analogous to coal-tar pitch is coke-oven pitch from 
 by-product coke ovens, used primarily for the production of coke. 
 The coking is, of course, a process of destructive distillation, and 
 the character of the tar, and ultimately of the pitch produced, 
 depends somewhat on the type of coke oven used and the method of 
 recovering the distillates. 
 
 Lewes 153 gives the analysis of what may be considered a typical 
 coke-oven tar as follows : 
 
116 Blacks and Pitches 
 
 Semet-Solvay Coke Oven Tar. 
 
 SPecific: QTAVILY” ~s..Scansasvsrscn an Merates« inet tenes 1-170 
 Light dil, 80—<370" ©. gel... ssa, ewacmepnenken aes 3°7% 
 Middle. oil, 170-230": C, oi...) ..s<sesahas sank da cena 9-8% 
 Creosote oil, 2B0—270° Cy oo. cecsceeccecccccccecceves 12:0% 
 Anthracene oil, over 270° Cy wscsscsacecetesnieenent 4:3% 
 PHGOI aii ove ca cdkn. cv nccadecun aaah ets on opcaiene n 67:0% 
 Water! i coves denuacsss Gigsy paadeosaearerciuts eae 2:3% 
 
 Blast-furnace coal-tar pitch is obtained from blast-furnace tar, 
 in its turn a by-product of the blast furnace when the latter uses 
 bituminous coal. Generally speaking, blast-furnace pitches are 
 more paraffinoid than other forms of coal-tar pitch, and owing to 
 their relatively high ash content (from the flue dust) are not so 
 valuable. 
 
 By-products are recovered from the large producer-gas plants, 
 of which several types are in use, and the tar is subsequently distilled 
 for the production of the usual fractions. 
 
 The problem of coal-tar distillation concerns us here only in so 
 far as it relates to the production of coal-tar pitch. Several types 
 of still are commonly in use, various methods of heating are employed, 
 and there are both continuous and discontinuous systems of tar 
 distillation in use, not only in this country but abroad. 
 
 Amongst the commonest types of continuous-distillation plant 
 in use in this country may be mentioned the systems due to Hird, 
 Wilton and the Chambers and Hammond system. | 
 
 Space forbids anything more than a brief outline of one of 
 these systems, namely, the Hird continuous system, a typical 
 installation of which is shown in the accompanying illustrations 
 (Figs. 16-19), which, together with the following account of the 
 working of the system, are taken from Warnes’s book.'*? 
 
 Briefly, the method in the Hird continuous system is as follows. 
 The crude tar is conducted from the storage tank into the regulating 
 tank; from this tank it flows to the steam preheater, then to the 
 first of the series of heaters, a constant head being maintained by 
 means of a float valve in the regulating tank. In passing through 
 these heaters the temperature of the tar is raised by its receiving 
 heat from the various distillates leaving the stills as they pass 
 through the coils. During its passage the tar is deprived of prac- 
 tically all the contained water and the crude naphtha. The vapours 
 of these materials pass into a common main, and thence through 
 the tube of a coil condenser, in which they are condensed. ‘The 
 condensed liquids then pass through a sight box and a separator, 
 and thence to their respective receivers. 
 
Coal-tar Pitch and Allied Pitches 117 
 
 After its passage through the heater-coolers the tar flows through 
 the coil in the pitch cooler, and while doing this its temperature is 
 further raised, whilst that of the pitch is correspondingly lowered. 
 On leaving the pitch cooler the temperature of the tar may be 
 
 
 
 
 
 
 
 —, 
 | 
 
 wi 
 IAS 
 
 
 
 ait La hh 
 0 
 
 
 
 
 
 
 
 . iW 
 455 : 
 oa a 
 a 
 
 
 
 
 
 teed (tif Ba 
 ‘ / X oe av 1 Ww) 
 
 
 
 Fia. 16.—Plan of Hird’s Continuous Distillation Plant. 
 
 from 120° to 200° C., according to the original composition of the 
 tar. If the original water content has been high, much of the heat 
 will have gone into the removal of water during the passage through 
 the heaters. 
 
 The tar is now distilled for its light oil creosotes, etc., by adjust- 
 ing the heating of the stills, so that as the tar flows through them 
 in succession it shows such temperatures as have previously been 
 
‘ea Hibs 
 
 “qUuB[ qd UOlMel[Msiq 1B4-[V0D snonulzUoO Ss pIlH— LT “OL 
 
 
 
 
 
 pre ae ee — 
 
 PoE 3 
 ware ee ee ee 
 
 Dine ee, 
 
 
 
 
 
 
 
 2S 
 
 5 sine eet, 
 
 
 
 
 
 118 
 
Coal-tar Pitch and Allied Pitches 119 
 
 found to give desirable oil fractions. The anthracene distillation is 
 helped by live steam as usual in tar distilling. 
 
 The residue from the last still is liquid pitch, and this passes 
 from the still into the pitch cooler, through which it travels on its 
 way to the pitch bay, and during its progress it gives up much of 
 its heat to the crude tar passing through a pipe immersed in it, on 
 its way to No. 1 still. The temperature of the pitch on leaving the 
 cooler is such that it practically inhibits the emission of irritating 
 fumes so often observed when running off pitch in the intermittent 
 systems of tar distillation. 
 
 With such a plant it is possible to adjust the temperatures so as 
 to obtain continuously uniform fractions of any desired boiling 
 point, whilst at the same time the pitch can be varied to meet any 
 desired twisting point. Moreover, this plant may be worked with 
 a coke-oven installation (Figs. 16, 17, 18 and 19). 
 
 Coal tar pitches show the following ranges according to Abra- 
 ham : 
 
 TABLE X XVI. 
 
 Characteristics of Various Tar Pitches. 
 
 Gas-works |Coke-oven| , Piast Producer- 
 
 furnace gas 
 sere ee ag coal-tar | coal-tar 
 Se were pitch pitch 
 (Test 1) Colourin mass... | Black Black Black Black 
 
 (Test 2a) Homogeneity at 
 
 PO Bie cancsis 2 Variable | Variable | Variable | Variable 
 (Test 2b) Homogeneity 
 
 when melted... | Uniform | Uniform | Uniform | Uniform 
 (Test 4) Fracture ......... Conchoidal| Conchoidal| Conchoidal| Conchoidal 
 (Test 7) ere gravity at 
 
 I Ae dims caes 1-15—1-4 | 1-20—1-35] 1-2—1:3 | 1-2—1-35 
 (Test 13) Odour on heating Penetrating odour characteristic of all 
 coal tar pitches 
 
 (Test 15b) Fusing point (Cube 
 
 method) ...... 90—345° F. 
 (Test 19) Fixed carbon ... | 30—45% | 20—45% | 10—30% | 20—45% 
 (Test 21a) Soluble in carbon 
 
 disulphide ...... 55—90% | 60—85% | 50—75% | 60—85% 
 (Test 216) Non-mineral mat- 
 
 ter insoluble ... | 10—45% | 15—40% | 15—35% | 15—40% 
 (Test 2 lc) Mineral matter. 0—1% 0—1% 10—20% | 0—2% 
 (Test 35) Sulphonation 
 
 TOMAS .cisncses 0—5% 0—5% 5—20% 0—5% 
 
 
 
 Carbon 90—95%, hydrogen 3—5%, sulphur 0:-5—1%, 
 nitrogen 0-2—1-:2%, oxygen trace to 2%, 
 
LORS 1e}-[eoH snonuyzU0D 8. pPIy—'sl “OL 
 
 2 
 yi oo 
 Psa -> 
 
 ? 
 
 AMA 3 oh ate a isfy 4s Saye 
 ‘ . A : wee 7 
 
 
 
 --e=--— a a ae as 
 
 120 
 
‘quelq uolyeyysiq 1ey-[vop snonulzuo) 8. paly—6l “OI 
 
 Ra 
 
 Se as ; 
 Se 
 Rae SS ees 
 
 
 
 
 
 os, 
 
 
 
 ares 
 
 
 
 
 
 
 

 
 
 
Coal-tar Pitch and Allied Pitches 121 
 
 All the pitches are largely soluble in carbon disulphide, 
 benzol, coal-tar distillates, carbon tetrachloride and chloroform. 
 They are only partially soluble in petroleum distillates and 
 turpentine. 
 
 Concentrated nitric and. sulphuric acids char and decompose coal- 
 tar pitch, though if diluted the acids effect only slow disintegration, 
 whilst hydrochloric acid (concentrated or dilute) and solutions of 
 the caustic alkalies and ammonia have no effect. Air and water 
 appear to be without action, but the softer pitches on exposure to 
 the weather gradually harden, owing to the drying out of the oily 
 constituents. 
 
 Coal-tar pitch is a complex mixture of hydrocarbons mainly 
 belonging to the aromatic series, basic and non-basic nitrogen 
 compounds and oxygenated compounds, all of high boiling point 
 and ‘‘ free carbon ”’ (see Chap. X). According to Marcusson, coal- 
 tar pitch consists of “free carbon,” high molecular weight hydro- 
 carbons, coal-like resins, soluble tar bitumens, phenols, cresols and, 
 in addition, three distinct tar resins respectively soluble in benzol, 
 carbon disulphide and pyridine; in addition, compounds of sulphur 
 and nitrogen are present. The resins are said to be aromatic 
 - compounds of high molecular weight, and the one soluble in benzol 
 will absorb oxygen, being thereby transformed into a mixture of 
 the two other resins. On this property, so it is suggested, mainly 
 depend the drying power and resinification capacity of coal-tar 
 _ pitch. 
 
 According to H. Tindale,*® coal-tar pitch can be separated into 
 four constituents—oils boiling up to 300° C., “ petrolenes,”’ ‘‘ asphalt- 
 enes ” and “free carbon.” In vertical retort tars, asphaltenes are 
 said to occur in amounts of 25—30% and in horizontal retort tars 
 to the extent of 35—40%. 
 
 The handling of solid pitch has practnted problems consequent 
 on its tendency to produce ulcerous and cancerous growths and 
 inflammation of the eye,!*! and this handling is now the subject of 
 Home Office regulations. Incidentally, one may remark that, being 
 brittle in cold weather, fatal explosions due to coal-tar pitch have 
 been recorded, as the pitch dust is more highly inflammable than 
 coal dust of the same degree of fineness.1® 
 
 According to T. Howard Butler,1®* one of the most successful 
 modern methods of dealing with coal-tar pitch is to allow it while 
 hot to run into pans holding approximately half a ton. When the 
 pitch is cold the pans are picked up by a crane and swung into 
 railway trucks. 
 
122 Blacks and Pitches 
 
 REFERENCES. 
 
 148 Statistical Department, Board of Trade, February 1925. Private 
 communication to the author. 14° Journ. Inst. Pet. Tech., 1916, III, 9. 
 160 “* Constitution of Coal ’’ (Monograph), Marie C. Stopes and R. V. Wheeler, 
 H.M. Stationery Office, London. 1°! ‘ Brown Coals and Lignites,’? W. A. 
 Bone, J. Roy. Soc. Arts, No. 3662, Jan. 26th, 1923. 15? “Coal Tar Dis- 
 tillation,’? A. R. Warnes, 3rd ed., Ernest Benn, Ltd., 1923. 15% ‘‘ The Car- 
 bonisation of Coal,”’ by V. B. Lewes, Ernest Benn, Ltd., London. 154 Clark 
 and Wheeler, J. Chem. Soc., 1913, 108, 1704. 155 Jbid., 1914, 105, 2562. 
 156 Bone, Pearson, Sinkinson and Stockings, Proc. Roy. Soc., 1922, A., 100, 
 582. 157 J. Ind. Eng. Chem., 1916, 8, 841. 158 J. Soc. Chem. Ind., 1918, 
 37, 23. 158¢ Journ. of Gas Lighting, 52, 169. 159 Trans. London and Southern 
 District Junior Gas Assoc., 1911-1912, p. 43. 1° English Patent No. 
 163,199. 191 Brit. Med. Journ., Dec. 9th, 1922. 162 Report of H.M. Chief 
 Inspector of Factories and Workshops, 1914. 18 ‘‘ Modern Practices in Coal 
 Tar Distillation,’ J. Soc. Chem. Ind., 1918, 237. 
 
 Bibliography—Coal-tar Pitch and Allied Pitches. 
 
 ** Modern Gasworks Practice,’’ Alwyne Meade, London, 1921. ‘“* The 
 Practical Chemistry of Coal and its Products,” A. E. Fmdley, London, 1921. 
 ‘“The Constituents of Coal Tar,’’ by P. E. Spielmann, London, 1924. Bone 
 and Sarjant, Proc. Roy. Soc., 1919, A, 96, 119. Tideswell and Wheeler, 
 J. Chem. Soc., 1919, 115, 619. Porter, U.S. Bureau of Mines, Bulletin 82, 50. 
 Munro, J. Soc. Chem. Ind., 1922, 414, 1297. Bedson, Trans. Fed. Inst. Min. 
 Eing., 16, Newcastle, 1899. Anderson and Henderson, J. Soc. Chem. Ind., 
 1902, 21, 237. ‘‘ Researches on Coal,’ 8. Roy Illingworth, J. Soc. Chem. 
 Ind., 1920, 39, 1llv and 13417. ‘‘ Ultimate Composition of British Coals,” 
 T. J. Drakeley, J. Chem. Soc., 1922, 121, 211. ‘‘ The Problem of Gas Works 
 Pitch Industries and Cancer,”’ John Murray, London. Thorpe, ‘“ Dictionary 
 of Applied Chemistry,” Vol. III, 1922. ‘The Constitution of Coal,” W. A. 
 Bone, J. Soc. Chem. Ind., 1925, 44, 2917. Distillation of Tar—English 
 Patent, 224,305 of 1923. E. V. Evans, “A Study of the Destructive 
 Distillation of Coal,” Gas Journ., 1924, 165, 483, 550, 629; 167, 447, 515, 580. 
 
CHAPTER XVI 
 MISCELLANEOUS. PITCHES 
 
 Wood-tar Pitch from Hard and Soft Woods—Wood Distillation—Rosin 
 Pitch—Peat and its Distillation Products—Peat-tar and Lignite-tar 
 Pitches—Water—Gas and Oil-Gas—Tar Pitches and their Properties. 
 
 Wood-tar Pitch. 
 
 THE treatment of wood by destructive distillation has already 
 been touched upon in Chapter III, but in this chapter the volatile 
 distillates will be discussed rather than the residual charcoal. During 
 the period 1915—1918 wood distillation acquired considerable 
 importance in this country. Several factories were erected and 
 equipped with modern wood-distillation plant, only to fall into 
 _ disuse and ultimately to be dismantled on the resumption of peace- 
 time conditions. 
 
 According to a report of the U.S. Department of Commerce,!* 
 there were in 1923 in the United States 123 establishments engaged 
 in wood distillation—77 utilising hard woods, 26 utilising soft woods, 
 each with appropriate plant for recovery of the by-products, whilst 
 the remaining 20 utilised different types of wood and did not recover 
 the by-products. 
 
 In the forest regions of the Continent of Europe wood distillation 
 is also of great importance, and it has been computed that prior to 
 1914 the yield of pure pine pitch from the distillation of resinous 
 woods in the Russian forest area was about 124,000,000 lbs. annually, 
 and this was largely exported from Archangel and constituted the 
 Archangel or pine pitch of commerce. 
 
 Woods may be divided into two main classes, viz : 
 
 Hard woods—maple, birch, beech, oak, poplar, elm, willow, ash, 
 chestnut. The distillation of these aims at the production of wood 
 alcohol, acetate of lime, tar and charcoal. 
 
 Resinous or Soft Woods—-pine, fir, larch, spruce, cedar. The 
 distillation of these aims at the production of turpentine, wood oils, 
 tar and charcoal. : 
 
 The yield of pitch and its characteristics naturally are influenced 
 by the type of wood distilled, and as a result of large-scale experi- 
 ments on the destructive distillation of wood, J. C. Lawrence 1844 
 finds that 
 
 (a) Rich, soft resinous woods, like the firs and pines, yield 
 about 8-4% pitch. 
 (b) Lean soft woods yield 3:9% pitch. 
 (c) Hard woods, like oak, birch, elm, yield about 5-2% pitch. 
 123 
 
124 Blacks and Pitches 
 
 Slightly different types of retorts and by-product recovery plants 
 are used in distilling the two main types of wood, but in both cases 
 the heavy oils or tars are fractionally distilled to yield pitch, hard 
 wood yielding hardwood-tar pitch and the soft resinous woods 
 yielding pine-tar pitch. 
 
 These two classes of pitch vary somewhat in their physical 
 properties, owing to initial differences in the wood and to slightly 
 different types of plant used, and in duration and temperature of 
 the destructive distillation of the wood. 
 
 They comply mainly with the following characteristics, according 
 to Abraham : ®° 
 
 Hardwood-tar Pine-tar 
 pitch. pitch. 
 
 (Test 1) Colour in Mass ’.........cssnsce0s Black Brownish black 
 (Test 2) Homogeneity  ......cccxceesres Uniform Uniform 
 (Laat . 4) oF raceuire £4 gs oss sas caies oh dunpees Conchoidal Conchoidal 
 (Test 7) Specific gravity at 77°F. ... 1-2—1-3 1-I—1-15 
 (Test 15a) Fusing point (K. & 8.) ...... 100—200° F. 100—200° F. 
 (Test 19) Fixed carbon ....s.0.....es0ss 15—35% 10—25% 
 (Test 21a) Soluble in carbon disulphide. 30—95% 40—95% 
 (Test 21c) Mineral matter .........,..00000. 0—1% 0—1% 
 (Test 37) Saponifiable constituents ... 5—25% 10—40% 
 (Test 37c) Resin acids  .........csccseseeens Up to 20% Up to 40% 
 
 Wood-tar pitch consists largely of the methyl esters of the 
 cresols, such as guaiacol and of the trihydric phenols, and on the latter 
 probably depend its antiseptic and preservative properties. The 
 pine pitches contain larger amounts of rosin acids than are found 
 in the hardwood pitches. The contrasting properties of these two 
 types of pitch are given by H. K. Benson and L. L. Davis.1® 
 
 A sample of English hardwood-tar pitch examined by the author *4 
 showed the following results—black colour, uniform, very brittle 
 and with hackly fracture and a black streak : 
 
 Specific gravity at 155° OC, oic..avececsasenuegunnen 1-114 
 
 Melting point (cube method) ..........ccssscsceseees LIT, 
 
 Freed war bon Nt fasiasasenssaasle te sacs caceeeeeeenee 16:2% 
 Mineral migtter oiccsssiveris obeys edcnhasaadensaseeent arin 0:092% 
 Soluble in carbon disulphide ............seeesseeeees 63:7% 
 
 Odour On Mating i... wwc-esspahsaeckeaabegaee cee very creosotic. 
 
 The sample was almost completely soluble in cold absolute 
 alcohol. ) 
 
 Rosin Pitch—This is somewhat similar in composition and 
 properties to pine pitch. Oleo-resin, the sap of the long-leaf pine, 
 is composed of turpentine and rosin, and by distillation is separated 
 into these two main constituents. The rosin, in turn, is distilled 
 
Miscellaneous Pitches 125 
 
 either with or without the use of superheated steam, or even in vacuo. 
 If destructively distilled at atmospheric pressure, it yields about 
 16% of rosin pitch and various rosin oil fractions. According to 
 V. Schweizer,1** when rosin is distilled with superheated steam, 
 the following yields are obtained : 
 
 MMR TARER ANE eau ls savas vewe'nscaisvecsiuacht ne cets 5:5—5-8% 
 NE ER a iehins «rundown et ied ans oben iad vhaad 11-25—12:0% 
 ERA is a. ols cennipeg idcenatuanedanaenes 49:0—50:8% 
 UMMMEIREOUSSS EE Cassi deta acts scenesaves¥ecsecs 10:25—10-65% 
 MNT RCE cs sea0 5 5 cis DEN ad) af tas owe cs ad» Sed dees 18-0—19-:0% 
 
 Rosin pitch is usually hard and friable, contains considerable 
 quantities of resin acids (10—45%), but is free from fatty acids 
 and does not weather well. 
 
 Peat-tar Pitch.—Peat, a compressed mass from the decomposition 
 of vegetable matter in a swampy environment, consists of a mixture 
 of water, iron and calcium salts, vegetable fibres and humus acids 
 and small amounts of nitrogenous and sulphur compounds. By 
 many it is considered as the precursor of lignite in that chain of 
 metamorphic changes which, commencing with the cellulose of 
 woody fibre, leads ultimately to coals. The great obstacle to its 
 commercial exploitation has always been the difficulty of satis- 
 factorily dehydrating it and the process known as ‘“‘ wet carbonising ”’ 
 has offered the greatest possibilities. Now that the main difficulties 
 inherent in its utilisation are said to be overcome by the proposals 
 of W. Wieland,*®’ its use should become more general. 
 
 Dry briquetted peat is distilled to a limited extent by a variety 
 of methods, and yields gas, tar, ammonium compounds and a coke 
 hard enough to be used in blast furnaces. The tar, a black, viscid 
 liquid, is produced to the extent of about 9—10% of the air-dried 
 peat, and on distillation dry peat tar yields the following, according 
 to Abraham : 
 
 TABLE XXVII. 
 Distillation Products from Peat. 
 
 After 
 Sends, Purification. 
 YN % 
 MNO SE Eso Sc pide hse bav's vnc dus’ ong aig 16 12 
 PY MAID oii v sects tcc censanveses 30 25 
 TAIL OE cscs» sigs sv dah hie > wsaans 15 13 
 MORNE IES, ~ on chins Sevaiccaessiediandaceubs 12 2 
 MMROMEL DOI a pe kneccinonssxnngseaararessh x 16 16 
 MAL Lia, Gates > .abkuAsibds She asende»toernike = 12 
 
 (as a ERR i a RR eg ree 11 20 
 
126 Blacks and Pitches 
 
 EK. Bornstein and F. Bernstein 1°° devised a process for the 
 destructive distillation of crude peat, and the resulting tar, when 
 dehydrated, yielded 47% of a paraffinoid pitch. According to 
 G. T. Morgan and C. E. Scharff,1®* the redistillation of peat tar 
 yields about 5:8% of a typical soft pitch with asphaltic properties. 
 
 Ordinarily peat-tar pitch has much the same properties as 
 lignite-tar pitch, and has poor weathering properties. 
 
 Lngnite-tar Pitch—Brown coals (Lignites), cannel coals and 
 bituminous shales all yield tars on destructive distillation, and these 
 tars subsequently give rise to pitch, allied on the one hand somewhat 
 to coal-tar pitch and on the other hand to wood-tar pitch. 
 
 Large deposits of lignite occur in the U.S.A., in Canada, to some 
 extent in Australia, one small deposit at Lowe, in Derbyshire and 
 in Germany. In the last-mentioned country low-temperature 
 retorting 17° is resorted to in considerable extent. 
 
 Retort lignite is treated in one or two ways, thus : 
 
 1. Low-temperature destructive distillation. 
 2. Solvent extraction for the removal of montan wax and 
 destructive distillation of the residue. 
 
 In the case of distillation, this takes place between 270° and 
 500° C., and the yield of tar is about 5—10% of the lignite distilled. 
 The tar, which is of buttery consistency at the ordinary temperature, 
 is dark brown to black in colour; and is composed of liquid and 
 solid members of the paraffin and olefine series of hydrocarbons, . 
 together with small amounts of hydrocarbons of the benzol series 
 and higher phenols and their derivatives (see Chapter X). There 
 are also present about 10—25% of solid paraffin and 0:5—1:5% _ 
 of sulphur. Asphaltic substances, however, according to Mar- 
 cusson, are scarcely present. 
 
 The tar is fractionated into crude oil (33%), a paraffinoid dis- 
 tillate (60%), small amounts of other distillates and about 5% of 
 lignite-tar pitch, or it may be continued to the stage of coke. 
 
 Lignite-tar pitch is characterised by the presence of phenols, 
 the absence of insoluble carbonaceous matter, the presence of small 
 amounts of paraffin wax, and almost complete solubility in benzol; 
 these characters serve to distinguish it from coal-tar pitch. From 
 wood-tar pitch it is distinguished by its content of sulphur and 
 paraffin, and from asphalt and resin pitch by the diazo-reaction 
 indicating the presence of phenols. 
 
 In the following table E. Graefe 1° has indicated the differences 
 between lignite-tar pitch and many other residual pitches, thus : 
 
Miscellaneous Pitches 127 
 TABLE XXVIII. 
 
 Comparison of some Residual Pitches. 
 
 Residue ; 
 after Sulphur. Todine 
 benzol value. 
 
 extraction 
 Lignite goudron , 66-5 
 TE EMRE Che 69 pie. sovcses. « . 93°7 
 i, a cacue re . Ҥ 50-0 
 NRT gi dnc sguccvevescce . . 140-0 
 Petroleum pitch I : 49-4 
 a re ii . : 70:3 
 a ee aL . 103-5 
 
 
 
 In Germany, by reason of its solubility in petroleum distillates, 
 lignite-tar pitch finds extensive use in the manufacture of cheap paints. 
 
 The retorting of bituminous shales is also a source of shale tar 
 and shale-tar pitch in many parts of the world, not only in the U.S.A., 
 but in Australia, Germany and Scotland. Shale tar and the resulting 
 pitch are more paraffinoid than asphaltic in character, and generally 
 are closely similar in properties and composition to the corresponding 
 products from lignite. 
 
 Water-gas and Oul-gas Tar Pitches. 
 
 These and their corresponding tars are allied on the one hand 
 to petroleum asphalts, and on the other to coal-tar pitch. In 
 modern water-gas plant, anthracite coal or coke undergoes partial 
 combustion and is then subjected to the action of steam, leading 
 to the production of “blue gas,” : C+ H,O=CO+H,. This 
 gaseous mixture is mingled with gas-oil and the resulting mixture 
 passed through a superheater at 650—700°C., to crack the oil 
 vapours. In this way a certain amount of tarry formation occurs, 
 and below are given analyses of some of these tars. 
 
 TABLE XXIX. 
 
 Water-gas Tars.\74 
 
 
 
128 Blacks and Pitches 
 
 Oil-gas tars arise in the cracking or heating of petroleum alone 
 in closed retorts, some 10% of tar being recovered in one of the 
 processes employed. 
 
 Water-gas tar and oil-gas.tar, when suitably dehydrated, are 
 distilled by similar methods to those employed with coal-gas -tar, 
 yielding corresponding pitches, which resemble coal-tar pitch, from 
 which they differ in containing paraffin to a certain extent and in 
 their low content of “free carbon”? (2—15%), 7.e., non-mineral 
 matter, insoluble in carbon disulphide. 
 
 REFERENCES. 
 
 164 Ind. Hing. Chem., Feb. 20th, 1925. 147 J. Soc. Chem. Ind., 1918, 37, 7. 
 165 J, Ind. Eng. Chem., 1917, 9, 141. 18® “The Distillation of Resins,” 
 2nd Edn., 1917, Scott, Greenwood & Son. 157 Chem. Zett., 1912, 36, 
 1305. 158 J. Gas Lighting, 1915, 129, 731. 19° Hconomic Proc. Roy. 
 Dublin Soc., 1915, II, 161. 17° Daniel Bellet, Rev. gen. Sct., 1917, 28, 118. 
 171 L. Schmitz, ‘‘ Die Flussugen Brennstoffe,” 1912. 
 
 Bibliography. 
 
 A. C. Craig, A. E. Dunstan, F. M. Perkin and A. G. V. Berry, J. Inst. 
 Pet. Tech., 1918, 4.  ‘‘ Die Braunkohlenteer Industrie,” Edw. Graffe, 
 1906... The Brown Coal Distillation Industry of Germany,” D. R. Steuart, 
 J. Soc. Chem. Ind., 1917, 36, 167. ‘‘ Shale Oils and Tars,’’ Scheithauer. 
 Hs i ea J. Inst. Pet. Tech., 1916, 2, 162. W. Dominick, Petroleum, 
 1924, 20, 1891. 
 
CHAPTER XVII 
 FATTY ACID PITCHES 
 
 Subdivided into Stearine Pitch, Cotton-seed Pitch and Wool Pitch—Saponi- 
 fication of Fatty Oils—Cotton Black Grease and Wool Grease—Dis- 
 tillation Plant and its Operation—Characteristics of Various Stearine, 
 Cotton and Wool Pitches—Bone-tar Pitch. 
 
 A GREAT variety of names has been used to designate the product 
 Fatty-Acid Pitch, thus: ‘“ Fettpech”’ (German), ‘‘ Kerzenteer ”’ 
 (German), goudron (French), candle pitch, cholesterol pitch, fat 
 pitch, stearine pitch and many others. 
 
 It may be stated generally that all the fat pitches are residues 
 remaining after the distillation of fatty matter in superheated 
 steam, whether aided or unaided by diminished pressure. 
 
 The present author prefers the following subdivisions : 
 
 (a) Stearine Pitches resulting from the distillation of fatty 
 acids produced by saponification of the familiar glyceride- 
 containing fatty oils, such as tallow, palm oil, palm kernel oil, 
 whale oil, etc. 
 
 (b) Cotton-seed Pitch, which is the residue after distillation 
 of cotton black grease. 
 
 (c) Wool Pitch, which remains after distillation of wool 
 grease or Yorkshire grease, this grease being chemically a 
 wax, and not a glyceride. 
 
 The first important reference to stearine pitch is in a paper by 
 E. Donath and R. Strasser,1”2 who mention that in the distillation 
 of fatty acids used in candle manufacture, 2—7°% of tarry matter 
 remains in the still, and that on redistillation of this residue with 
 superheated steam at 300°C. a black asphaltic mass of stearine 
 pitch remains. It further appears that this pitch was used at 
 Roubaix in the production of an oil gas. 
 
 (a) Stearine Pitches.—The raw material concerned in the manu- 
 facture of these pitches is the mixed higher fatty acids produced from 
 fatty oils by saponification, and it is necessary to digress briefly here. 
 
 Our ordered knowledge of the subject of saponification was 
 advanced when the constitution of fatty oils was established by the 
 researches of Chevreul,!”4 Berthelot,175 and Wurtz,!7* when it was 
 shown that these oils consist mainly of the triglycerides of the 
 fatty acids. 
 
 The triglycerides may be represented by the general formula 
 
 CH,—OR /OR 
 H—OR or (,H,COR 
 CH,—OR OR 
 
 9 129 
 
130 Blacks and Pitches 
 
 where “R” represents any fatty acid radical, usually the radical 
 of a higher fatty acid (see Chapter X). 
 
 Following the work of the early pioneers, the change which 
 occurs when a fatty oil is boiled with a solution of a strong base 
 such as caustic soda may be expressed by the formula 
 
 CH, OR NaOH CH, OH 
 CHO R + NaOH = CH + 3NaOR 
 CH 20R NaOH CH, OH 
 
 where R is the acid radical of any higher fatty acid, and for sim- 
 plicity’s sake the acid radical is supposed the same throughout. 
 
 The study of the hydrolysis or saponification of fatty oils has 
 been carried on largely by Geitel,1?* 178 Lewkowitsch,1” 18° Mar- 
 cusson 181 and others to the conclusion that this hydrolysis is stage- 
 wise and may be indicated thus : 
 
 Triglyceride —-> diglyceride —-> monoglyceride —-> glycerol + fatty acids. 
 
 These reactions are interdependent, the rate of formation of the 
 glycerol being conditioned by the rate of formation of the mono- 
 glyceride and so forth, the whole operation consisting of three simul- 
 taneous bimolecular reactions taking place in the same system, but 
 not necessarily at the same rate, the older view of a quadrimolecular, 
 direct action being regarded now as untenable. The present author 
 has given elsewhere 1°? a full résumé of the investigations of this 
 aspect of the subject. The demarcation into stages cannot be 
 observed on a technical scale, partly because it is impossible to 
 isolate or separately demonstrate the existence of the intermediate 
 products of the stagewise hydrolysis. 
 
 Theoretical considerations show that water or steam is essential 
 to saponification, but its use alone makes the completion of the 
 reaction almost impossible on a technical scale, and in consequence — 
 various means have been introduced to hasten the reaction, and in 
 modern industrial practice resolve themselves into : 
 
 1. The acid process, in which fats are boiled with concentrated — 
 sulphuric acid. 
 
 2. The Twitchell process, use being made of aromatic oleo- 
 sulphonic acids. 
 
 3. The autoclave process, in which the fats are heated in 
 contact with high-pressure steam in the presence of small 
 amounts of alkaline-earths such as lime, magnesia, etc. 
 
 4. The fermentation process, which depends on the lipolytic 
 
 » action of certain enzymes, such, for instance, as that in the 
 castor seed. 
 
Fatty Acid Pitches 131 
 
 The technique of the foregoing processes need not be described 
 here, but the reader is referred to the publications of Lewkowitsch 18° 
 and to a résumé by the present author contained elsewhere.18? 
 
 Much of the early work on saponification concerned itself mainly 
 with the chemical aspect of the subject, but in recent years the 
 extension of our knowledge in relation to surface tension effects, 
 colloidal phenomena, and the importance of emulsification and the 
 part that these play in many familiar industrial operations, indicate 
 that physical considerations may outweigh purely chemical ones 
 when dealing with a heterogeneous system such as exists in the 
 emulsion of fatty oil and aqueous alkaline or acid solution, which 
 constitutes the reaction mixture in industrial saponification. 
 
 The function of the particular reagents, used technically in the 
 various industrial methods of saponification already enumerated, 
 becomes that of effecting intimate association of the reactants, 
 and the accumulated evidence indicates that this association is best 
 achieved by emulsification. The author has recently summarised 
 the current views relative to the physical aspect of saponification.184 
 
 In the acid process of saponification usually applied in the case 
 of tallows and palm oil and similar fats, a change takes place in the 
 reaction, leading to the production of y-stearolactone, 
 
 CH,;(CH,),3;°CHCH,CH,CO, 
 Ose ea 
 CH; (CH,),;CH—CH,(CH,),COOH 
 OH 
 this is of importance in the subsequent distillation.1®° 
 
 The distillation of the fatty acids is carried out by means 
 plant of the type shown in Fig. 20. In this particular plant the 
 still is of cast iron, 7 ft. in diameter and 7 ft. in depth from the 
 top joint of the still, the body of which is cast in one piece, on 
 to which is bolted a cast-iron cover, the whole being supported as 
 shown. The contents of the still are heated by superheated steam 
 by means of an internal steam coil. The principal fittings include 
 a draw-off cock, feed valve, steam valve, safety valve and a self- 
 recording thermometer, enabling the temperature of the still contents 
 to be noted during the progress of the operations. The fatty acids 
 are distilled in steam, and for this purpose an open steam coil 
 through which passes superheated steam is passed into the still. 
 
 The cover is surmounted by a copper head with a copper vapour 
 outlet connected to the condenser, which is a series- of air-cooled 
 vertical copper pipes, as indicated in the diagram. Each pair of 
 tubes is provided with a bottom outlet separately connected to a 
 copper worm condenser in a water-cooled worm tank, with suitable 
 
 
 
 and i-hydroxy-stearic acid, and 
 
132 Blacks and Pitches 
 
 outlets for the various distillates. The end of the condenser passes 
 to a water-sealed fume-absorbing condenser or gas pan, of the 
 cascade type, with water inlet valve and vapour vent pipe open to — 
 the atmosphere at the top. The still shown is arranged with a 
 tubular feed heater, heated by means of the exhaust steam from the 
 heating coil in the still. 
 
 Stills of similar design are in use for direct fire heat, the stills 
 being then appropriately set in fire-brick with a suitably built flue, 
 which carries the hot gases round the outside of the bottom of the 
 still. Suitable setting of the still in the brickwork is of importance, 
 so as to ensure the bottom of the still, rather than the higher parts 
 of it, getting the bulk of the heating effect of the hot flue gases. 
 When direct fire heat is used, it is necessary that a long cast-iron 
 outlet pipe to carry away the pitch be cast solid with the body. 
 
 In an actual distillation the best practice is to work with steam 
 of high superheat and a low pressure of about 5 to 8 lbs./sq. inch; 
 the fatty acids distil over in the steam and are condensed in the series 
 of air-cooled condenser pipes, and run away to collecting pails, 
 arranged under the worm condenser, whilst the steam, together 
 with any uncondensed lower fatty acids, and such products as carbon 
 monoxide, carbon dioxide, acrolein and uncondensable hydro- 
 carbons—the products of decomposition and pyrolysis in the still— 
 pass away to the cascade condenser. 
 
 The aim of the distiller is to recover as much fatty acids from 
 the still as possible, and thus reduce to a minimum the yield of 
 pitch. The amount of recovery is determined somewhat by the 
 nature of the material distilled, the extent to which the original 
 fatty oil was saponified and the extent to which the distillation is 
 carried. For fatty acids, testing up to 95—98% acidity (as oleic — 
 acid), the yield of pitch is lower than for fatty acids testing only 
 90% acidity. The longer the distillation is continued the less the 
 yield of pitch and the less saponifiable matters such pitch will 
 contain and the harder its consistency. 
 
 The author records hereunder the results of some actual large- 
 scale distillations carried out under his control : 
 
 Acidity (as Average 
 Autoclaved fatty acids from oleic acid) yield of 
 of autoclaved pitch. 
 material 
 : of 
 Oo 0 
 Tallow (English beef) — ................06 96-3 3-7 
 Palan oil (Niger). cctsskescpeexnepstearesect 94:5 3°8 
 Whale ou (NOS) iscssasiess yb cee wed ten 94—96-2 8—9 
 
 Fish oil (J Bpan) 6.5.2. Se eer 90—92 10—12 
 
(‘F O°" ‘uopuoyy ‘oueyT ooyg “pF ‘gp “py ‘sueoyg pue suog yyouueg Ag) 
 ‘quel UoHyeyysig ploy AWeq— 0s “OLA 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

 
Fatty Acid Pitches 
 
 133 
 
 Characteristics of some stearine pitches from whale oil fatty 
 
 acids examined by the author.*4 
 
 Sample A Sample B. 
 (Test 1) Colour in mass ............ Black Black 
 (Test 2) Homogeneity ............ Uniform Uniform 
 OeeeG 2)  PLAOUITG . 2.660... ks eee e sees None—sticky Brittle 
 ee ENAMEL 1 hii Si vvecidincecsees Bright Bright 
 (Test 7) Specific gravity ............ 1:016 @ 15:5° C. 1-046 @ 15-5° C, 
 (Test 15) Melting point (drop 
 SEENON) Woks eveiices. 37:9° C. 68-5° C, 
 (Test 21a) Solubility in CS, ......... 97-:1% 90-9° 
 (Test 21c) Mineral matter ............ 0:-48% 7-23% 
 MONS iach eaneViw tense ens TTAL% 73:19% 
 En Ro ee 10-35% 10-49% 
 Oxygen (by difference) . 12:06% 9:09% 
 ROUONS. PS eae eiea cs vias trace al 
 OE eee nil gs 
 (Test 37d) Saponification value 67:8 104 
 F.F.A. (as oleic acid) 10:7% 5:41% 
 (Test 44) iodine OL a 126 97-9 
 
 Characteristics of some stearine pitches from palm oil fatty 
 
 acids examined by the author ; *4 
 
 Sample A. Sample B. 
 (Test 1) Colour in mass ............ Black Black 
 (Test 2) Homogeneity _............ Variable Uniform 
 Pe PA OUULG Fy psocednenscdveccieee None—pliable Fairly brittle 
 
 RTT ENISUIO  cssechescensascessees 
 (Test 7) Specific gravity .......... 
 (Test 15) Melting point (drop 
 
 Dull 
 
 0:982 @ 15-5° C. 
 
 Bright 
 1-060 @ 15:5° C. 
 
 WOOUNOG) -. cissiveevass 43° C. 60-7° C 
 (Test 21a) Solubility in CS, ......... 94-62% 93-7% 
 (Test 21c) Mineral matter ............ 2°98% 33% 
 Oe eee 79-6% 76-80% 
 I VOPOM ON Seu ceccesscasenes 11-26% 9-289 
 Oxygen (by difference) 6-16% 10-62% 
 Sulphee eee ke ect ie Skies ail nit 
 (Test 37d) ee en value 58-3 93-4 
 A. (as oleic acid) 8-7% T4% 
 (Test 44) Iodine DRPMAALES chen pry nos’ en's é 118-5 94°3 
 
 (b) Cotton-seed Pitch.—Vegetable oils intended for edible purposes 
 require to be refined in order to remove free fatty acids, suspended 
 impurities and albuminous matter, colouring matter, and the 
 resinous fatty unsaponifiable matter always found with the crude 
 oil, and cotton oil is of particular interest in this connection. Crude 
 cotton oil as obtained from the seed by crushing varies in colour 
 from reddish-brown almost to black, the latter colour being that of 
 Bombay cotton oil as ordinarily produced in English oil mills. 
 
 The first stage in the refining of this cotton oil is to heat it in 
 large tanks tapering downwards to a cone piece at the bottom, the 
 tanks being provided with suitable stirring gear and heating coils. 
 Caustic soda solution of specific gravity about 1-125 is slowly run 
 
134 Blacks and Pitches 
 
 through sprinkler pipes on to the heated agitated oil, with the result 
 that combination takes place between the free fatty acids in the 
 oil and the caustic soda, and ultimately soap separates out. On 
 completion of the neutralisation and with cessation of the agitation 
 the soap collects at the bottom of the tank, leaving clear bright 
 neutral cotton oil at the top. The material which separates out is 
 known as Cotton-seed Mucilage or Cotton Soap-Stock, and its 
 composition is 30—40% cotton oil, 50—60% cotton fatty acids in 
 the form of their soaps, traces of water, free caustic soda, albuminous 
 matter and colouring matters. 
 
 Usually the cotton-seed mucilage is acidified with hot dilute 
 sulphuric acid, and as a result a black grease, Cotton Black Grease, 
 is thrown to the surface. This Cotton Black Grease, after settling, 
 consists approximately of about 30° neutral cotton oil, 60% cotton 
 fatty acids, albuminous matter, black colouring matter, fatty 
 unsaponifiable matter and traces of water. It is sold to the dis- 
 tillers on the basis of 98% fatty matter soluble in carbon disulphide. 
 Sometimes the separated black grease is saponified by one or other 
 of the usual methods to which reference has already been made, 
 in order to break up the neutral oil. A better method of achieving 
 this end is to saponify the Cotton-seed Mucilage first before proceed- 
 ing to the conversion into black grease. 
 
 Ultimately the cotton black grease is subjected to steam dis- 
 tillation, the same plant and procedure being adopted as that 
 described in connection with fatty acids, with the result that light- 
 coloured distilled cotton fatty acids pass over and a residue of 
 Cotton Pitch or Cotton-seed Pitch or Cotton Stearine Pitch remains. 
 The yield of pitch averages 10—20% of the weight of black grease 
 distilled, representing 1—2% by weight of the original cotton-seed 
 oil before neutralisation. The lower the percentage of neutral oil 
 in the black grease, the smaller will be the yield of pitch, for on 
 distillation the neutral oil does not always split to yield fatty acids 
 which distil over in the steam, but a certain amount of breaking up 
 into hydrocarbons and condensation products occurs, and these 
 products remain in the pitch. 
 
 Cotton-seed pitch is usually produced in three grades: hard 
 and brittle, rubbery, and soft, is usually black, uniform to variable 
 in homogeneity, with a fracture varying from nil to conchoidal 
 and testing generally within the following limits : 
 
 (Test 7) Specific gravity at 15-5° C. ............ 0-90—1-20 
 
 (Test 15) Melting point (drop method) ......... Variable 
 
 (Test 21c) Mineral matter — ..i.fiinseccsenenssenens 2—5% 
 
 (Dest 28) “Subpiens 20 ore ond tex one voad aotee aeeemaiaee Maybe up to 1% 
 (Test 37a) Acidity (as oleic acid) .........c..eeeeee 2—50% 
 
 (Test 37d) Saponification value (usually) ...... 80—120 
 
Fatty Acid Pitches 135 
 
 (c) Wool Pitch Wool grease is the oily material naturally occur- 
 ring in sheep’s wool and is extracted from the wool clip when this is 
 suitably boiled with an alkaline soap solution and subsequently 
 acidifying the liquor, whereby the grease is caused to rise to the top, 
 and after removal, and appropriate purification and dehydration, 
 it is obtained as a light to dark-brown grease of m. p. 30—40° C. 
 
 Chemically wool grease is an animal wax and consists of esters 
 of the higher monohydric alcohols and higher monobasic fatty 
 acids (see Chapter X), such as cetyl palmitate, C,,H,,CO-OC,,H,, 
 (the ester of cetyl alcohol and palmitic acid), a certain amount of 
 free higher fatty acids, and considerable amounts of unsaponifiable 
 matter, the latter consisting of higher monohydric alcohols and 
 cholesterol. Normally glycerides are not constituents of wool 
 grease. 
 
 Wool grease is recovered in great quantity in the woollen centres 
 of the West Riding of Yorkshire, where many of the Municipal 
 Sewage Works have installed special plant for the recovery of the 
 grease from the industrial effluent. This grease is subjected to 
 steam distillation, without previous saponification, the same type 
 of plant being utilised as for the distillation of fatty acids. 
 
 A number of typical samples of Yorkshire wool grease tested 
 in the author’s laboratory showed the following results : 
 
 TABLE XXX. 
 
 Analyses of Wool Greases. 
 
 
 
 Inorganic Unsaponi-| Saponi- Acid. Todine 
 matter. Water. fiable fication value. value. 
 matter. value. 
 % % % 
 
 | ee 1-4 0-82 39-65 101:3 55-5 25-73 
 
 i: Seren 1:77 0-89 43:5 121-7 66:9 29-5 
 Gas. 0-6 0-75 29-3 131-4 69-3 26:48 
 Dee. 0-44. 2-1 36-6 135 70-2 27-1. 
 
 According to G. F. Pickering,!°® wool pitch has the following 
 characteristics : 
 
 Soft to hard, dark brown to black, usually bright and of 
 uniform consistency, specific gravity at 15-5°C., 0-97—1-0, 
 melting point 90—160° F., ash 0-5—5:5%, saponifiable matter 
 about 7% in hard pitches to 30% in softer samples. 
 
 Free fatty acids 0:75—15%, with 6% as an average, iodine 
 value 35—45, 
 
136 Blacks and Pitches 
 
 The various fatty-acid pitches (stearine, cotton and wool pitches) 
 vary somewhat in their chemical and physical properties, due to 
 differences in the materials from which they are made. According 
 to the method employed in the preparation of the fatty acids, 
 these bodies contain, in addition to the saturated and unsaturated 
 fatty acids, small amounts of neutral fats, hydroxy-acids, anhydrides 
 and lactones, fatty unsaponifiable matter and colouring matter. 
 In the case of cotton black grease all the foregoing may be present, 
 with the addition of albuminous matter and a larger percentage of 
 neutral fats than found with the fatty acids. Wool grease, of 
 course, contains no glycerides, but considerable amounts of higher 
 alcohols and some cholesterol. | 
 
 During distillation of these raw materials saturated fatty acids 
 generally distil away first, but some of the unsaturated acids, such 
 as oleic and those of higher unsaturation, are partly polymerised 
 and partly suffer decomposition, being transformed into saturated 
 and unsaturated hydrocarbons of the naphthene type (see Chapter X). 
 
 Some portion of the i-hydroxy stearic acid present in the fatty 
 acids (when the acid process of saponification has been bai under- 
 goes change thus to iso-oleic acid : 
 
 ag eres Mc tree —_> 
 ati ne stearic acid 
 CH,;(CH,),—CH(CH,),COOH + H,O 
 iso-oleic acid 
 (a solid isomer of oleic acid) 
 
 Condensations and intramolecular changes between some of the 
 components in the still may also take place, and there is also a 
 certain amount of cracking (pyrolysis), leading to the production 
 of hydrocarbons, not only from the fatty acids and neutral fats, 
 but (in the case of wool grease) also from the higher alcohols and 
 cholesterol. : 
 
 These pitches, therefore, may be regarded as complex mixtures of 
 saturated and unsaturated fatty acids and condensed fatty acids, 
 saturated and unsaturated hydrocarbons, some neutral fat, 
 anhydrides and lactones, and in the case of wool pitch, cholesterol 
 and the higher alcohols. 
 
 In view of the contrasting features of the several conflicting 
 theories accounting for the genesis of. petroleum and the asphalts, 
 a detailed examination of the fatty acid pitches is of scientific 
 interest and importance from the point of view of the possible 
 formation of petroleum from animal matter and fish blubber. 
 
Fatty Acid Pitches 137 
 
 All fatty acid pitches are converted into more or less infusible 
 and insoluble and somewhat elastic masses on exposure to the 
 atmosphere for long periods or even by heating to about 350° C. 
 out of contact with the air. A sample of medium-soft pitch from 
 whale oil fatty acids left exposed by the author *4 for two months in a 
 porcelain dish in the laboratory formed a tough, difficultly soluble 
 skin on its surface. The iodine value, originally 123-8, diminished 
 to 102:5 in the case of the surface skin formed. The weather- 
 resistant properties of these pitches, due to the saponifiable matter 
 they contain, makes them specially of value in the manufacture of 
 certain japans and varnishes and in the production of certain 
 - waterproofing materials. 
 
 Bone-tar Piich—In the dry distillation of degreased bones 
 (mentioned in Chapter IIT) a distillate, known as bone oil, bone tar, 
 Dippel’s oil, is produced as a by-product to the extent of 10—25% 
 by weight of the bones. Fractional distillation of this tar yields 
 Bone Pitch to the extent of about 23% of the tar. This pitch is 
 somewhat intermediate in its properties between asphalts and 
 fatty acid pitches. It is usually a hard, jet-black, very bright solid 
 with a conchoidal fracture with m. p. about 100°C. It usually 
 contains small amounts of sulphur, derived doubtless from ne 
 albumen in the bones from which it originates. 
 
 REFERENCES. 
 
 172 Chem. Ztg., 1893, 17, 1788. 4174 Chevreul, ‘‘ Récherches chimiques sur 
 ‘les corps gras d’origine animale,’’ Paris, 1815-1823. 175 Berthelot, ‘« Chimie 
 organique fondée sur la synthése,’’ Paris, 1860. 17° Wurtz, ‘‘ History of 
 _ Chemical Theory.” 177. 178 Geitel, J. prakt. Chem., 1897, 55, 429; 1898, 
 57, 113. 179% 180 Lewkowitsch, Proc. Chem. Soc., 1899, 190; Ber., 1900, 89. 
 181 Marcusson, Zeit. angew. Chem., 1913, 26, 173. 182 H. M. Langton, 
 Journ. Oil and Colour Chem. Assoc. y 1922, 29, 41. 183 “ Technology and 
 Analysis of Oils, Fats, and Waxes,” 1923. 184 Hf. M. Langton, J. Soc. Chem. 
 Ind., 1923, 42, 517. 185 J. Lewkowitsch, J. Soc. Chem. Ind., 1897, 392. 
 
 Bibliography—Fatty Acid Pitches. 
 
 D. Holde and J. Marcusson, Mitt. kénigl. techn. versuchamt, 18, [3], 147. 
 Kassler, Chem. Rev. Fett-Harz-Ind., 1902, 9, 49. D. Wesson, J. Soc. Chem. 
 Ind., 1907, 26, 595. E. Donath, Chem. Rev. Fett-Harz-Ind., 1905, 12, 42 
 and 73. E. Donath and B. M. Margosches, Chem. Revue, 1904, 194. 
 *Stearin Pitch,’ H. Meyer, Seif. Zeit., 1914, 44, 394. ‘‘ Distinguishing 
 between Petroleum Residuums and the Various Fat Pitches,’? A. R. Lukens, 
 The Ohemist Analyst, 1917, 20, 3. ‘‘ Fatty Acid Distillation Plants,”’ 
 O. H. Wurster, Chem. and Met. Hng., 1921, 25, 651—656. 
 
CHAPTER XVIII 
 
 THE WEATHERING AND AGEING OF BITUMINOUS 
 MATERIALS 
 
 Effects of Exposure to Air, Sunlight and Moisture—The Light Sensitiveness 
 of Asphalt. 
 
 THE principal uses of bituminous materials, both natural and 
 artificial, are in the manufacture of bituminous fabrics such as 
 roofing felt, the waterproofing of damp courses, in electric insulation, 
 in the manufacture of paints, varnishes, japans, in roadway and 
 pavement construction and in a variety of other ways closely allied 
 to the foregoing modes of employment. All these varied usages 
 involve exposure in a greater or lesser degree to the action of moisture, 
 sunlight and air, and comprised in what is termed weathering. 
 This exposure involves changes, which may be negligible or im- 
 portant, in the physical and chemical condition of the bituminous 
 substances. 
 
 M. Toch 18° noted that some petroleum asphalts are unsuitable 
 for making bituminous paints, and he has cited as an example a pure 
 petroleum residual asphalt which, applied in a good continuous coat 
 on cast-iron pipes in a cellar, lasted 3—4 years, whereas on the roof 
 of a building exposed to direct sunlight the petroleum asphalt 
 underwent complete decomposition in 20 days, with the liberation 
 of “free carbon.” His experiments indicated that this action was 
 inhibited by incorporating an opaque pigment. Moreover, fatty 
 oils (containing the triglycerides) are not affected in this manner 
 and retard the disintegration of petroleum asphalts when blended 
 with them. 
 
 Investigations of the weathering of bituminous substances have 
 been conducted by P. Hubbard and C. S. Reeve,18? by 8S. R. Church 
 and J. M. Weiss,18° by C. S. Reeve and B. A. Anderton 1®° and by 
 C. 8. Reeve and R. H. Lewis. The changes may be of a com- 
 plicated character, being the cumulative effect of one or more of 
 the following reactions. 
 
 Evaporation.—The more volatile constituents on exposure to 
 air and the sun’s rays are gradually lost. The tars particularly 
 are liable to loss in this way, and the softer pitches harden owing 
 to the evaporation of the more oily constituents, and usually the 
 higher the temperature the greater the volatilisation. 
 
 Oxidation.—Exposure to the air brings this about more rapidly 
 as a rule at high than at low temperature, and the action is two-fold, 
 involving on the one hand direct union between oxygen and the 
 bituminous substance, and on the other hand elimination of a 
 
 138 
 
The Weathering and Ageing of Bituminous Materials 139 
 
 portion of the hydrogen in the form of water, and the conversion 
 ef the hydrocarbons in the bituminous substance to hydrocarbons 
 of a lower degree of saturation, thus: 2C;H, + O, —> 2C,H,-, + 
 2H,0, . ° 
 
 Carbonisation.—This really represents carrying to the stage of 
 completion the oxidation of hydrogen and the consequent formation 
 of “‘free carbon” in the bituminous substance; the reaction is 
 most rapid in the presence of sunlight. Scrapings from a bitu- 
 minous surface which has undergone such carbonisation are found 
 to consist largely of fine particles of carbon. 
 
 Polymerisation.—This is due to a condensation or polymerisation 
 of the molecules, and is shown by a hardening or setting of the 
 bituminous substance. This takes place to a greater or lesser 
 extent on heating bituminous substances; particularly is this 
 the case with fatty acid pitches, and the more glycerides and the 
 less fatty acids they contain, the more does this setting to a hard 
 infusible mass take place. 
 
 Effects of Moisture.—The action of moisture may be two-fold— 
 actual absorption of water and a gradual washing out of soluble 
 constituents. Generally, though, this factor—the action of moisture 
 —is less far-reaching than the previously enumerated factors. 
 
 Many of the harder naturally occurring asphalts suffer no change 
 due to ageing or weathering, but we have seen that in the case of 
 Trinidad lake asphalt a rapid hardening at the surface of the lake 
 takes place. A hardening takes place also at the exposed surface 
 of many petroleum residual asphalts, and in the case of many residual 
 pitches. In an extended experience of fatty acid pitches derived 
 from a variety of raw materials the author has observed how these 
 on exposure become dulled and hardened at the surface, due to the 
 action of light and air, and actual analyses revealed in these cases 
 a decrease in the iodine value and an increase in the oxygen content 
 of the fatty pitch. 
 
 According to P. E. Spielmann,®*" the change occurring in the 
 case of many residual bitumens is twofold and involves a slow 
 surface hardening, due to the action of light and air on the residual 
 oils remaining in the bitumen, and a slower “ settling down.’ He 
 makes the tentative suggestion that this latter phenomenon is due 
 to “internal molecular rearrangement,’ and in support of this 
 view quotes the determinations given in the table at top of p. 140, 
 which were obtained on a sample of residual bitumen. 
 
 The increases in asphaltene content and in fusing point are con- 
 sidered to support the theory of “‘ internal molecular rearrangement.” 
 
140 Blacks and Pitches 
 
 Penetration of Ageing Residual Bitumen. 
 
 
 
 Time in At surface. 3 mm. below Asphaltenes. 
 days. surface. 
 0 46 a 315% 56-0 
 7 42 45 — — 
 43 38 (35—41) 43 (41—44) é eee 
 205 25 (20—30) 39 (36—42) ag ga 
 487 23 (21—26) 33 (30—40) 38-9% 58-3 
 
 Spielmann®** also advances the view that the immediate surface 
 hardening—besides being due to oxidation, the action of light and 
 polymerisation—may be correlated with the presence of paraffin 
 wax or ceresine in the bitumen. 
 
 Summarising, it appears that weathering and ageing affect 
 bituminous substances by making their colour lighter, destroying 
 their homogeneity by the formation of free carbon and dulling the 
 surface. ‘There is usually an increase in the specific gravity, hard- 
 ness, viscosity, melting point, flash point, and decreases in the 
 case of the amount of volatile matter, solubility in carbon disulphide 
 and 88° petroleum naphtha. The amount of saponifiable consti- 
 tuents remains unchanged. Such physical properties as ductility, 
 tensile strength and adhesiveness also undergo diminution. 
 
 The sensitiveness of bituminous materials to light, regarding 
 the matter largely from a physical aspect, may be considered in 
 this chapter. This light-sensitiveness of bitumen has been known 
 since the time of J. N. Niepce, who in 1824 produced a portrait 
 as a result of experiments with a solution of “ asphalt,” and the 
 _ property has been made use of in a number of photo-mechanical 
 processes. More recently the study of the subject has been revived. 
 Maderna,!® for example, has found that different portions of a 
 bituminous complex possess a light-sensitiveness differing in magni- 
 tude, though in each case of the same quality, and Paul Gédrich 1% 
 found that petroleum asphalts free from paraffins are, relatively 
 to other asphalts, the most sensitive towards light. 
 
 J. Errera 1% has made a careful study of the light sensitiveness 
 of Judean asphalt and in this connection classifies its constituents 
 into a-, B-, y-resins, the last-named being sensitive to light and 
 existing in the colloidal condition, the asphalt as a whole being 
 both molecularly and colloidally dispersed. Whatever be the 
 underlying cause of this light sensitiveness, it appears to be estab- 
 lished that it is intimately associated with colloidal phenomena. 
 
The Weathering and Ageing of Bituminous Materials 141 
 
 REFERENCES. 
 
 _ 186 “ The Influence of Sunlight on Paints and Varnishes,” J. Soc. Chem. 
 Ind., 1908, 27, 311. 187 “‘ The Effect of Exposure on Bitumens,” J. Ind. 
 Eing. Chem., 1913, 5, 15. 188 Proc. Amer. Soc. Testing Materials, 1915, 15, 
 275. 189 “*The Effects of Exposure on Tar Products,” J. Franklin Inst., 
 463, Oct. 1916. 19 J. Ind. Hng. Chem., 1917, 9, 743. 192 J. Soc. Chem. 
 Ind., 1909, 28, 694. 1% “The Light Sensitiveness of Petroleum Asphalt,” 
 Chem. Zeit., 1915, 39, 832. 1% Trans. Faraday Soc., 1923, 19, 314. 
 
 Bibliography. 
 
 W. W. Wall, ‘‘ Process Year Book,”’ 26, 133. Eder, ‘‘ Geschichte der | 
 
 Photographie,’ 1905, i, part I, p. 133. Nicolescu-Otin, Bull. Soc. Scv. 
 
 Acad. Roumaine, 1920. Meigs, J. Ind. Hng. Chem., 1917, 9, 655. Rosinger, 
 
 Kolloid-Ztg., 1914, 15, 177. Klimont, Oesterr. Chem. Ztg., 1914, 16, 309. 
 Wilson, Highway Engineer and Constructor, 1920, June 27. 
 
CHAPTER XIX 
 BITUMINOUS FABRICS 
 
 Roofing Felt—Floorings and Floor Coverings—Bituminous Cements, Insulat- 
 ing Coverings and Papers—Waterproofing and Damp Coursing—Manu- 
 facture and Uses of Bituminous Fabrics. 
 
 BiruminiseD fabrics are utilised in roofing, flooring, water- 
 proofing, and for sheathing and insulating purposes, and they will 
 be considered in detail under these headings. 
 
 Sheet Roofings.—These are composed of a single layer or a plurality 
 of layers together, each layer being composed of a woven or felted 
 fabric, which is saturated and/or coated with suitable bituminous 
 materials, the bituminous materials being chosen largely on their 
 ability to withstand weathering.1® 
 
 Both felted and woven fabrics are chosen, but the former are 
 preferable, as they absorb a larger amount of bituminous material, 
 and to a more unform degree than is found possible with the latter 
 type of fabric. Roofing felt is composed of a variety of fibres, the 
 following, together with their approximate relative durability, 
 expressed numerically, being, according to Abraham : *° 
 
 WOO]. sciscensenceneseyspedee gue da'nms gens kaa cuneate 100 
 COUEOR nn. ie esclenaanegnassuntadunsecnsadanes sean een ne nanan 60 
 Jute and manilla ...4..0s00.0. seseeeay seen tions 5h eee 0s nnn 44. 
 Paper (including mechanical and chemical wood fibres). 20 
 
 Wool fibres, besides being the most durable, are least affected by 
 exposure to moisture and the sun’s rays: incidentally they are 
 the most expensive. Numerous substitutes for felting have been 
 suggested, such as leather, cane, straw, coconut, moss, peat, sea 
 grass, and numerous patents relative thereto have been taken out, but 
 in most cases the above substitute fibres result in increasing the 
 brittleness or porosity of a felt with which they are incorporated. 
 In regard to woven fabrics, the most usual are hessian (of jute 
 fibres), and duck (of cotton fibres). 
 
 The details of manufacture of the fabrics, and the technique of 
 their saturation or coating with appropriate bituminous material, 
 and the type of machinery employed are outside the scope of our 
 survey. The materials generally to be recommended for the 
 impregnating of the fibres and fabrics should be of soft consistency 
 at ordinary temperature, with a penetration of more than 60 at 
 25° C. (Test 9b), a consistometer hardness (Test 9c) of less than 15 at 
 25° C., and a fusing point of 80—140° F. 
 
 The following classes of bituminous materials have been recom- 
 mended in this connection for saturation : 
 
 Group I. Pure native asphalts, petroleum residual asphalts, 
 142 
 
Bituminous Fabrics 143 
 
 blown petroleum asphalts, and the pitches from wood tar, rosin, 
 bone tar and fatty acids, either singly or blended to give the right 
 consistency. If they are too hard they may be blended suitably 
 with the softer grades of the pitches already enumerated, as well 
 as with animal or vegetable fatty oils and wool grease. 
 
 Group IJ. Oil-gas-tar pitch, water-gas-tar pitch, coal-tar pitch, 
 coke-oven pitch, wood-tar pitch and rosin, bone-tar and fatty acid 
 pitches, alone or in combination, or, if necessary to effect the desired 
 consistency, with the corresponding liquid tar, previously evaporated 
 to expel the highly volatile oils, etc. 
 
 The tar and pitch compositions in Group IT (except the fatty acid 
 pitch) are used mainly for manufacturing multiple-layered prepared 
 _ roofings, and for single-layer tarred felt, which is to be used in built- 
 up roofings of more than one course of fabric. Only Group I 
 compositions are recommended for general use, on account of their 
 greater weather-resisting characters. 
 
 The characteristics of tar and pitch composition should corre- 
 spond with those for a soft coal-tar pitch, 2.e., one having a fusing point 
 120—160° F. (cube method). Saturating mixtures prepared from 
 asphaltic products should comply with the following characteristics, 
 according to particulars given by Abraham : 
 
 (1) Viscosity at the saturating temperature should be as 
 low as possible to accelerate the speed of absorption by the 
 fabric. 
 
 (2) Penetration at 25° C. should be in excess of 60, and con- 
 sistency less than 15, to prevent brittleness in the fabric. 
 
 (3) The susceptibility factor should be as low as possible, 
 and preferably below 30. 
 
 (4) The saturant should be ductile. 
 
 (5) Fusing point 110—150° F., and as low a content of 
 volatile matter as possible—less than 3% after 4 hours at 
 500° F. 
 
 (6) Preferably 97° or more of constituents soluble in carbon 
 disulphide. 
 
 (7) Should be weatherproof. 
 
 The most commonly used materials for saturation purposes are 
 soft coal-tar pitch, soft residual asphalt, and soft blown petroleum 
 asphalt. A recent U. 8S. Government 1% specification for coal-tar 
 pitch for roofing purposes requires that the pitch when freshly 
 melted should be glossy black, and not dulled in one week ; m. p. 60— 
 65-5° C., specific gravity 1-22—1-34, ductility—minimum 50 cm.; 
 
144. Blacks and Pitches ‘ 
 
 free carbon content 15—30%. In the distillation test not more | 
 than 12% by weight should distil over below 300° C., and the 
 distillate should show a specific gravity not less than 1-03. 
 
 Asphalt for use with asphalt saturated rag felt for roofing and 
 water-proofing, and in the construction of mineral-surfaced roofing 
 on an incline of not more than 3 in. to the foot, may be either 
 petroleum residual asphalt or a mixture of refined Trinidad asphalt 
 with petroleum asphalt, according to the latest U.S. Government 
 specification,’®? which requires that the material when freshly 
 melted shall be uniformly glossy and on ageing for one week its 
 surface shall not become dull or show any separation of oil, grease, or 
 wax. The asphalt shall further have : 
 
 M. p. (ball and ring method) 60—73° C. 
 
 Penetration 25—50 at 25° C., with a minimum of 10 at 0° C. 
 
 Ductility at 25° C. to be 5 cm., preferably not less than 20. 
 
 Soluble in carbon disulphide (in case of petroleum asphalt 
 only) minimum 99%. 
 
 Ash (in case of mixture containing Trinidad asphalt), mini- 
 mum 20%. 
 
 The ash must show the characteristics of that from Trinidad 
 asphalt. | 
 
 Naturally a great variety of modifications of the foregoing methods 
 of using bituminous materials in the construction of roofing fabrics 
 are to be found, and many might be enumerated. For instance, 
 an impregnating material resembling rubber and suitable for coating 
 millboards and textile fabrics has been patented by O. Schreiber.!*® 
 Stearine pitch, wool pitch, or even coal-tar pitch or petroleum 
 pitch is heated, cold air forced through, and during this treatment 
 suitable oxidising materials are added. A somewhat similar material 
 from the point of view of its applicability can be obtained by treating 
 wool pitch with sulphur at temperatures up to 300° C.1% 
 
 Floorings.—Bituminous materials find considerable use in the 
 construction of floorings laid down in somewhat the manner of a 
 concrete floor, over which they have the advantage of a certain 
 resiliency. Both natural and artificial asphalts, with or without 
 suitable fluxing, are used, and mineral aggregates in the nature of 
 crushed limestone, finely-graded sand are added, and finely-powdered 
 pigments and coloured metallic oxides, such as red oxide of iron, 
 chromium oxide, etc., may be added to give a decorative effect .?°° 
 
 This type of floor covering is laid down whilst of plastic trowelling 
 consistency, the bituminous material being melted before admixture, 
 
 / 
 
Bituminous Fabrics 145 
 
 and the matrix on cooling hardens to a smooth, hard surface which 
 wears better than a concrete surface. 
 
 As coverings for floors, but used in a somewhat different manner, 
 there has grown up during the last fifteen years the manufacture of 
 substitutes for linoleums and the like, bituminous materials, notably 
 fatty acid pitches, being employed, the technique of which is 
 somewhat analogous to that of linoleum manufacture (cf. ‘‘ The 
 Chemistry of Drying Oils,’ by L. 8S. Morrell and H. R. Wood). 
 The finished product is prepared in rolls and laid down in squares 
 and strips. The use of stearine pitch in this connection was patented 
 during the World War,?°! and very considerable quantities of medium 
 soft stearine pitch found application in the manufacture of floor 
 coverings, where its plasticity, high viscosity and ready hardening 
 
 on exposure render it valuable. | 
 
 Bituminous Cements.—These are of plastic consistency and can 
 be utilised in the manner adopted for handling lime-mortar and 
 cement, and their use is for joining, filling in and repairing of damp- 
 proof masonry. They consist of : 
 
 1, Bituminous base with or without the addition of vegetable 
 _ oils, resins, etc. 
 2. Mineral matter such as finely-ground limestone, barytes, 
 - etc., as filler. 
 3. Fibrous matter such as shoddy, asbestos, slagwool, 
 cotton flocks, to bind together the bituminous base. 
 4. Volatile solvents such as petroleum products, wood and 
 tar distillates, in which the base will dissolve. 
 
 The bituminous materials should be blended to give a fusing 
 point (K. & 8.) of 135—175° F., a consistometer hardness (Test 
 9b) of 5—25 at 25° C., a susceptibility factor (Test 9d) below 25, and 
 almost complete solubility in the solvent used. Further, the 
 bituminous base or bases are melted together in the usual type of 
 varnish kettle over direct heat, cooled until the mass begins to thicken 
 and then the solvent is added. Alternatively, the ingredients of the 
 base may be acted upon by the solvent in a closed, steam-heated 
 and mechanically agitated tank. After the incorporation of the 
 base and solvent, the other ingredients are added until the requisite 
 _ pasty consistency is achieved. 
 
 Numerous acid-proof cements and acid-proof layers for floors 
 are in use containing coal-tar pitch and other pitches in admixture 
 with cement, fireclay, graphite, asbestos fibre, and other suitable 
 
 materials.2°2 The cements are particularly useful in the making of 
 10 
 
146 Blacks and Pitches 
 
 joints in chemical plant, earthenware pipes, etc., and the bituminous 
 material serves partly to bind together the various ingredients of 
 the cement, and further, in virtue of its resistance to air and 
 water, corrosive acids and chemicals generally, is invaluable in 
 chemical and allied works, where steam and acid and other chemical 
 fumes are encountered. 
 
 Water-proofing and Damp-proofing. 
 
 Their impermeability and resistance to the effects of moisture, 
 make many bituminous materials and pitches invaluable in 
 the prevention of the passage of moisture through porous 
 constructional materials. By damp-proofing, according to G. J. 
 Ward,?° is implied the prevention of the passage of water through 
 brick, concrete or stone by capillary action; water-proofing or damp- 
 coursing is the prevention of the passage of water under pressure 
 through the walls of tunnels, conduits, tanks, etc., and calls for more 
 than the comparatively thin layer of material which suffices to 
 exclude moisture in damp-proofing work. 
 
 According to Ward, a damp-proofing compound must have several 
 characteristics to fit in for its work. It must, first of all, yield a 
 film which will be impervious to water, and must be durable even 
 under decided temperature changes. It must be capable of easy 
 and rapid application, and must dry fairly rapidly, so that, if neces- 
 sary, more than one coat may be applied without any great loss of 
 time. It must bind well to the surface on which it is applied, and 
 must be inexpensive. 
 
 A great variety of damp-proofing compounds has been tried, but 
 bituminous varnishes have generally proved so satisfactory in this 
 respect that they are now consumed in very large quantities. 
 
 A bituminous varnish, to function satisfactorily in damp-proofing 
 work, must have certain definite properties.*°* In the first place, 
 the varnish must be of a durable nature, maintaining its elasticity 
 indefinitely. The percentage volatile at 100° C. is kept low as com- 
 pared with the bituminous varnishes commonly applied to structural 
 steel. This permits the attainment of a heavy consistency, which 
 is desirable in order that in application a fairly thick coating is 
 obtained. A thin coating applied to a porous surface, such as con- 
 crete, is drawn for some distance into the pores of the material, and 
 fails to make a seal unless a number of coats are applied. The 
 varnish must set within 8 hours, but may remain somewhat 
 tacky for a period of several weeks. Finally, it must possess ad- 
 hesiveness, bonding well to the surface on which it is applied, and 
 
Bituminous Fabrics 147 
 
 must be capable of acting as a foundation for plaster. The fact that 
 these materials may be plastered on directly is one of the important 
 considerations in their use. Experience shows, however, that the 
 presence of certain materials or combinations enhances the effective- 
 ness of the coating in its work. For instance, the presence of a 
 percentage of stearine or fatty-acid pitch may be found to impart a 
 desirable adhesiveness to the coating in addition to the great merit 
 this material possesses of stability and retention, unimpaired, of its 
 weathering and ageing properties after long exposure. 
 
 The only satisfactory criterion of the value of a bituminous 
 varnish for damp-proofing work is an actual test conducted in a 
 manner which parallels actual practice as nearly as possible. Two 
 coats should be applied to the clean, dry, slightly rough surface 
 selected, allowing sufficient time for setting between coats. It is 
 necessary to obtain perfect continuity of the coating, any bare or 
 thin places rendering the results worthless. The final coat of damp- 
 proofing varnish is left slightly rough, and a coat of plaster applied. 
 This is subsequently painted with a light-tinted flat paint. A 
 satisfactory damp-proofing varnish prevents any appearance of 
 moisture on the plastered wall, even when the outside of the wall 
 is subjected to the action of water for lengthy periods. 
 
 Coal-tar pitch for use in this way, where the pitch is not exposed 
 to a temperature in excess of 35° C., except during its installation, 
 ‘and where it is not subjected to vibration, should have the following 
 characters : 2°4 Freshly-melted, the material must have a uniform 
 black, glossy colour, and after ageing for one week must not become 
 dull or show any separation of oily constituents. The freshly-fractured 
 material must present a satin-black surface, m. p. (cube in water 
 method) 52—60° C., free carbon 15—30%, d 1:22—1-34, minimum 
 ductility 50 cm., and not more than 12% by weight, shall distil 
 below 300° C., and the density of the distillate must not be below 
 1-03. 
 
 Natural asphalt is, of course, similarly used for water-proofing 
 and damp-proofing, and a recent U.S. Government specification 29° 
 requires asphalt for such use to be black and glossy when freshly 
 melted; moreover, it must not become dulled in one week, it must 
 have m. p. 60—77°C., penetration at 25°C. 25—50, at 0°C. a 
 minimum of 10, and a maximum of 100 at 46°C. The ductility 
 should be not less than a minimum of 15 cm. The maximum 
 amount of volatile matter allowed is 1% at 63° C., whilst not less 
 than 99% of the asphalt must be soluble in carbon disulphide. 
 
148 Blacks and Pitches 
 
 Insulating and Sheathing Papers. 
 
 Paper is specially treated to enable it to take a water-proofing 
 material, either by coating, by saturation, or by both methods of 
 application, and such suitably water-proofed papers find great 
 application in the construction of cold-storage floors, insulated 
 rooms and spaces on ships, refrigerator cars for the transport of 
 perishable foodstuffs of all sorts, and in the lining of ice chests, the 
 object being to prevent the transfer of heat into enclosures, which 
 it is required should be kept cold, and conversely to prevent the 
 egress of heat from enclosed spaces requiring to be kept warm.?°6 
 
 Strong paper of open texture is the best to use in the manufacture 
 of insulating papers, and generally the greater the number of layers 
 used, the greater is the effectiveness of the insulated installation. 
 In practice, the paper is introduced in the floors, walls and partitions 
 of buildings between protective layers of wooden boards, one on 
 each side of the cavity containing the chief insulating material, 
 usually charcoal, cork or silicate cotton. 
 
 For water-proofing the papers, petroleum residual pitches of 
 asphaltic character and fatty-acid pitches find the most frequent 
 use. M, Dupré and 8. Icard 7°’ have patented the use of stearine 
 pitch for water-proofing paper and fabrics, either by direct applica- 
 tion or after solution of the pitch in a volatile solvent, and such 
 substances as tar or resin may be added to assist the formation of 
 a coating material. These coatings are odourless, impermeable, 
 very elastic, and when used in the form of pitch papers are excellent 
 damp-proof coatings for the walls of cold-storage rooms. 
 
 Cotton muslin strips 4—1 in. in width and 0-015—0-025 in. 
 in thickness, passed through melted bituminous materials to fill 
 up the pores of the fabric, form excellent coverings for electric 
 cables, owing to the very high specific resistance of most bitumi- 
 nous materials and pitches. Pure native asphalts, petroleum 
 residuals, blown asphalts, fatty-acid pitches, either alone or with 
 asphalts, are used, and they should be tacky and adhesive at room 
 temperature, and should retain this property as long as possible on 
 —exposure to the air. 
 
 The desiderata for bituminous materials for such work are a 
 consistency at 25° C. of less than 7, a susceptibility as low as possible, 
 fusion temperature 27—40°C., and after being maintained at a 
 temperature of 500° F. for 4 hours, the loss of volatile matter 
 should not exceed 5%. 
 
Bituminous Fabrics 149 
 
 Solid Impregnating Compounds. 
 
 Such compounds with a bituminous material as a basis are 
 prepared for field coils and stationary windings. The impregnation 
 is completed in one operation, the coatings are more chemically 
 inert, are better fillers and more resistant to moisture. The 
 temperature of impregnation for a “‘compound”’ is higher than 
 for an insulating varnish, but it should not be above 175° C., or the 
 cotton covering may be carbonised. These impregnating com- 
 pounds, unlike insulating varnishes, require no thinners and solidify 
 on cooling, rendering the enclosed parts insensible to vibration. 
 
 If an electrical machine be overloaded, the impregnating com- 
 _ pounds will, unlike the varnishes, soften and may even melt; and if 
 
 there be revolving parts, these may become exposed, owing to 
 centrifugal force. Generally, the natural or petroleum residual 
 asphalts and other materials used soften at 105—115° C., and do 
 not become appreciably fluid below 150° C. The materials used— 
 asphalt, stearine pitch, rosin and copal—are run together until 
 water has been expelled, and, in order to make them resistant to 
 mineral-oil, a certain amount of sulphur is incorporated. R. S. 
 Morrell 2° quotes the following as being typical of impregnating 
 compounds : 
 
 1. 2. 3. 
 100 parts neutral wool fat | 110 parts asphalt Stearine pitch heated 
 200 «4, asphalt 200 ~=«, crude ozokerite to 220—285° C. 
 50 =~«,, rosin 70  +«,, rosin 
 so. « «=6Crosin oil 
 
 (Andés) (Seeligman and Zieke, p. 426.) (Andés) 
 
 Being durable and elastic, and not cracking or running when 
 exposed to extremes of cold or heat respectively, the petroleum 
 pitches (preferably those of asphaltic character), by reason of their 
 high insulating properties, are valuable even alone in the manufacture 
 of electric cable insulations. But, as F. Dupré *° has shown, only 
 first-grade bituminous materials, whether natural or artificial, are 
 suitable for cable masses, viz., those with the requisite elasticity, 
 ductility and adhesiveness, and a fusing point of at least 75— 
 95°C. If use be made of those with a fusing point of only 40—60° C., 
 then the cable mass will lose its form when exposed to external 
 temperatures exceeding 20—30° C. 
 
 REFERENCES. 
 
 195 “* Roofing Materials Committee Report,’ Bull. Amer. Railway Eng. 
 Assoc., 1913, 14, 839. 19° U.S. Bureau of Standards, 1924, Circular 157. 
 197 U.S. Bureau of Standards, 1924, Circular 159. 19° German Patent 
 
150 Blacks and Pitches 
 
 208,378 of 1905. 419° German Patent 225,911. 9 English Patents 212,106 
 and 212,188 of 1923. 1 English Patent 121,777 of 1917. 2 “‘ The 
 Industrial Chemist,’”? May, 1925. 29% Oi and Colour Trades Journ., 1924, 
 65, 1789. 2794 U.S. Bureau of Standards, 1924, Circular 155. 2795 U.S. 
 Bureau of Standards, 1924, Circular 160. 2°% ‘‘ Modern Methods of Water- 
 proofing,” by M. H. Lewis, New York, 1914. °°? French Patent 385,805 
 of 1907. 298 ‘* Varnishes and their Components,” 1923, p. 305 (Oxford 
 Univ. Press). 7° Chem. Zeit., 1918, 42, 445. 
 
 Bibliography. 
 
 Fleming and Johnson, ‘‘ Insulation and Designs of Electrical Windings,”’ 
 1913. U.S. Bureau of Standards, 1924, Circular 162. S. E. Finley, English 
 Patent 219,150 of 1923. ‘* Insulation and Insulating Materials,” Dictionary 
 of Applied Physics, 3, 1922, Macmillan & Co. 
 
CHAPTER XX 
 BITUMINOUS PAINTS, VARNISHES, ENAMELS AND JAPANS 
 
 Nature of Bituminous Bases Used—Volatile Solvents to be Used—Bituminous 
 Paints and Varnishes Protective against Rusting and Exposure to 
 Chemical Agents—The Jellying of Asphalt Paints—Japans and their 
 Uses—Pitting of Japans. 
 
 oe 
 
 PAINTS, varnishes, enamels, black japans, Brunswick blacks, stoving 
 blacks are all prepared in the liquid state, and their consistency is 
 regulated by the amount and nature of the solvent incorporated 
 in the mixture. In this chapter attention will be confined to 
 such of the above manufactured products as contain a bituminous 
 base or material as an essential part of their composition, and, 
 furthermore, they will be considered from the point of view of their 
 composition, properties and uses. The technique of their manu- 
 facture closely simulates that of the manufacture of paints, varnishes, 
 etc., in general, and the reader is referred to any of the well-known 
 volumes dealing with paint and varnish manufacture for details of 
 plant and modus operandt. 
 
 Bituminous Paints.—These consist of a bituminous base, a 
 volatile solvent with or without the addition of vegetable drying 
 oils, resins, fillers, pigments, etc., intended to dry or set by the 
 spontaneous evaporation of the solvent, leaving a firm coat on the 
 object painted. Generally those bituminous materials are chosen 
 which will weather well on exposure to air, moisture and sunlight, 
 and which are unattacked by mineral acids, caustic alkalies, cyanides 
 and chemical fumes generally. One precaution that is necessary 
 is to avoid the use of a bituminous base in any environment which 
 will bring it into contact with the solvent action of any distillate 
 (either in liquid or vapour form) derived from the same source as 
 the bitumen itself, e.g., coal-tar pitch should not be used as a paint 
 or coating for materials which come into intimate contact with a 
 coal-tar distillate such as coal-tar naphtha. 
 
 The bituminous paints may be divided into four groups con- 
 taining : 
 
 (1) Native asphalts, asphaltites, residual petroleum asphalts 
 and all the pitches, with or without a filler, and suitable volatile 
 solvents. 
 
 (2) Bituminous substances, resinous substances (damar, 
 sandarac, rosin), with or without a filler, or a coloured pigment, 
 and suitable volatile solvents. 
 
 (3) In addition to bituminous substances, animal or vegetable 
 
 fats and oils such as linseed, tung, soya, fish, cotton, and perilla 
 151 
 
152 Blacks and Pitches 
 
 oils, raw or thickened, and in conjunction with driers, and 
 suitable volatile solvents. 
 
 (4) Bituminous substances, resins in combination with 
 animal or vegetable fatty oils with or without mineral fillers 
 and with or without pigments, and the addition of suitable 
 volatile solvents. | 
 
 The ‘‘ resins ’’ used may be common rosin, the damars, sandarac 
 and Manilla, Kauri and Congo copals. These resins readily com- 
 bine with the bituminous substances either by dissolving directly 
 in the solvent or by first fluxing together. 
 
 Vegetable and animal fats improve the weathering power of a 
 bituminous paint and therefore should be added in the role of a 
 flux. The harder the bituminous base and the higher its m. p. 
 the larger is the amount (%) of the fatty oil that can be incorporated 
 into the admixture. 
 
 Fillers added must be of low specific gravity, finely powdered 
 (they should pass through a 200-mesh sieve) and their function is 
 to harden a paint and also to cheapen it. 
 
 The solvents used in the preparation of bituminous paints 
 comprise the following classes : Se, 
 
 1. Petroleum Products—gasoline, naphtha (benzine), white spirit, 
 and kerosene and their sub-fractions. (White spirit is midway 
 between the low flash, boiling point and solvent power of gasoline 
 on the one hand and the higher flash, boiling point and solvent 
 power of the kerosene.) 
 
 2. Coal-tar Distillates—in the order in which they distil benzols, 
 toluols, xylols, solvent naphthas. 
 
 3. Wood Solvents—acetone oils, light wood oil, heavy wood oil 
 (creosote), wood turpentine, pine oil, rosin spirits and rosin oil. 
 
 4, Manufactured Chemical Solvents—comprising carbon disul- 
 phide, carbon tetrachloride and the non-inflammable chloro-com- 
 pounds such as C,H,Cl,, etc. 
 
 The comparative volatilities of some of the commercial solvents 
 generally used in bituminous paint manufacture are for 2 c.c. of 
 each solvent evaporated under identical conditions from a metal 
 surface 34 in. square, according to Abraham, as follows: 
 
 GS iii ahal saevsiesdertkn es ae 34 mins. Turpentine ,...0.s.0essees 142 mins. 
 OSES Mi ON cpaithea nes aeaney cn § 4, ,, Wood turpentine ...... 480 ,, 
 90% Dentol ne ceusesctses 134 ,, 80° gasoline ............... RES 
 560% benzol. .Siehizr 23 e 66° benzine .............0. 16 see 
 Commercial toluol ...... 33 3 Kerosene ...sséiesnschen Oe eee 475 5 
 
 Solvent naphtha ......... 107 
 
Bituminous Paints, Varnishes, Hnamels and Japans 153 
 
 The proportion of solvent used depends on (1) the nature of 
 the bituminous base, (2) the solvent capacity of the particular 
 solvent used, (3) the consistency required to be possessed by the 
 finished paint. Generally it varies in amount from 20% to 80%, a 
 smaller percentage being used in heavily-loaded paints for masonry, 
 and for sealing joints in compound sheet roofing. 
 
 Light-bodied paints containing a larger percentage of solvent 
 are used when it is desired to secure great penetration, rapid drying 
 properties or when the paint is for dipping purposes. 
 
 In general, the higher the susceptibility of the base the lower 
 will be the viscosity of the resultant paint. Petroleum residual 
 asphalts and the pitches from wood tar, water-gas tar, oil-gas tar, 
 and coal tar will form paints of lower viscosity than those fluxed 
 with asphaltites, blown petroleum asphalts and the non-susceptible 
 fatty-acid pitches. 
 
 Tar pitches produced by the destructive distillagion of bones, 
 wood, lignite and coal tar are more difficultly soluble than asphaltic 
 materials and rosin and fatty-acid pitches. Tar pitches dissolve 
 most readily in the following solvents, and in the order enumerated, 
 carbon disulphide, coal-tar distillates, and resinous wood distillates. 
 Of the other pitches, rosin pitch, fatty-acid pitches, bone-tar pitch 
 and lignite pitch are the most soluble, whilst oil-gas—tar pitch, 
 water—gas-tar pitch, wood- tar pitch and coal-tar pitch are the least 
 soluble. | 
 
 Dissolved in coal-tar naphtha, natural asphalts and such residual 
 asphalts as those from Texas and Mexican Petroleum, produce 
 excellent paints for the preservation of metal and outside iron and 
 steelwork, and these paints will withstand dampness and all forms 
 of chemical fumes and vapours. They are generally elastic and 
 do not chip. . 
 
 In a review of recent large-scale tests relative to the protection 
 of metal surfaces, H. A. Gardner 24° mentions the wide use of 
 bituminous coatings, which are often made by blending refined 
 coal-tar pitch, asphalt, linseed oil, and oleo-resinous varnishes, 
 subsequently thinning down with turpentine or light mineral thinner. 
 When coal tar is used in the manufacture of paints, it should be 
 refined. Ammonia and water in the tar are the active causes of 
 non-adherence to metal. The presence of large quantities of free 
 carbon or naphthalene in the tar will cause disintegration. For 
 refining, the crude tar may be heated to approximately 115° C., 
 holding it at that temperature until the water is evaporated. From 
 5 to 10% of lime may be stirred in, in order to neutralise the 
 
154 Blacks and Pitches 
 
 free acids. The tar may then be thinned with benzol or mineral 
 spirits. If a rapid-drying paint is desired, a quantity of resinous 
 varnish may be added. The addition of Chinese wood oil and 
 asbestine in a coal-tar paint made along the above lines will aid 
 in producing a film that is not so subject to “ alligatoring ’’ when 
 exposed to the sun. However, none of these paints is as durable 
 as a linseed-oil paint when exposed to the sun. Bituminous paints 
 of the above composition are used as coatings upon pipe-lines in 
 acid factories, tanks containing dilute acids, metal submerged in 
 water, and for other similar work. For such purposes it is generally 
 advisable first to coat the metal with a thoroughly hard-drying 
 prime coating, made by adding + lb. of litharge to a gallon of pre- 
 pared red lead or other rust-inhibitive paint. The bituminous 
 paint may then be applied. Steel mine timbers subjected to sulphur 
 water and gas, reservoir tanks containing water, submerged lock 
 gates, tunnel metal, etc., may be efficiently preserved from corrosion 
 by this method. 
 
 Jellying of Asphalt Paints. 
 
 In asphalt paints containing as part of the bituminous base 
 fatty-acid pitch, bone-tar pitch, rosin pitch or any other pitch in 
 which fatty acids or other similar acids are present, care is needed 
 in the choice of a pigment in those cases where the addition of 
 pigment is essential or desirable. Such pigments as chrome-green, 
 chrome-yellow, zinc oxide, 2.e., those containing a metallic base, 
 react with free fatty acids and rosin acids to form insoluble soaps 
 and cause a certain amount of solidification known as “ gelatinisa- 
 tion,” ‘‘ jellying”’ or “‘livering ”’ of the paints. In a recent con- 
 tribution to the discussion of this subject F. Singleton 211 contends 
 that the presence of water is an essential auxiliary factor in causing 
 “ livering ”’ or thickening. 
 
 Furthermore, a paint which jellies slowly in an unrefined solvent 
 will jelly more rapidly in the same solvent after the latter has 
 been subjected to acid and alkali refining. A thin paint on jellying 
 will precipitate and remain as two layers. Thicker paints may 
 settle out, but the incrustation of the layers so increases that in time 
 the two layers may appear homogeneous. 
 
 Recently the subject has received attention at the hands of H. C. — 
 Fisher,212 who has found that sulphuric acid will cause asphalt 
 paints to jelly, whether it is added to the base before dissolving, 
 to the solvent before dissolving the base in it, or to the finished 
 paint whether hot or cold. The rate of jellying appears to be 
 
 -— 
 
Bituminous Paints, Varnishes, Enamels and Japans 155 
 
 proportional to the amount of sulphuric acid present. Under 
 certain conditions such substances as caustic soda (NaOH) or 
 sodium sulphate will cause thickening of asphalt paints. In the 
 case of steam blowing of asphalts to remove sulphur compounds, 
 some of these latter may give rise to sulphur dioxide and ultimately 
 to sulphuric acid. 
 
 The rate of jellying of paints made from air-blown petroleum 
 asphalts is dependent on the nature and composition of the bitu- 
 minous ingredient and on the solvent used. <A petroleum residual 
 asphalt blown with air in contact with lime (CaO) jellies extremely 
 slowly, when contrasted with the same material not blown in contact 
 with lime. 
 
 Furthermore, bituminous bases that are hard and at the same 
 time possess tough and rubber-like properties (7.e., low susceptibility 
 factor, considerable elasticity, resilience and tenacity) when used 
 alone are apt to gelatinise after solution in the volatile solvent. 
 This is particularly the case with hard, rubbery, fatty-acid pitches, 
 such as those from cotton black grease distillation and wurtzilite 
 asphalt. The underlying causes in these cases are more obscure 
 and uncertain than in the case of paints where there is: possibility 
 of the formation of insoluble soaps. 
 
 In an account of the use of bauxite as a refining agent for 
 petroleum distillation by A. E. Dunstan, F. B. Thole and F. G. P. 
 Remfry 213 mention is made of bauxite as a polymerising agent, 
 polymerisation of unsaturated hydrocarbons largely present in 
 cracked spirit taking place in contact with the bauxite resulting in 
 the formation of gums of high molecular weight and boiling point. 
 Two methods of refining such cracked spirit are available. In one 
 of these the gumming polymers are washed out of the bauxite and 
 in the subsequent distillation remain in the still, and a non-gumming 
 distillate results. From the aspect of asphalt paints and their 
 liability to jellying the importance of removing these polymers 
 from bauxite-refined kerosene and white spirit is apparent. 
 
 Black Japans.—The term “Japan” is intended to define the 
 dark-coloured menstruum which is applied to the surface of metals, 
 wood, or other fabric and subsequently hardened by baking. The 
 japans are used mainly in high-class coach work, and the specific 
 purpose of black japans is the production of a brownish-black ground 
 of a particular translucence appearing as though their colour were 
 reflected from an under surface; in this respect the japans differ 
 from such pigmented preparations as black enamels, which appear 
 to reflect colour from the surface only. 
 
156 Blacks and Pitches 
 
 The base of cheap japans is solely a bituminous material, but 
 the highest grades contain, in addition, a vegetable drying oil with 
 or without the addition of some gum resin, and according to the 
 nature of the ingredients and the method of treatment the japans 
 may vary from an opaque black to a translucent brown—but all 
 are extremely hard, tough and resistant to abrasion. 
 
 The bituminous materials used are solid and semi-solid native 
 asphalts, such as the purest forms of gilsonite, Barbados and 
 Trinidad manjak, and in some cases residual asphalts from aromatic- 
 base petroleums having the property of hardening on baking. 
 Toughness may be imparted by fluxing with a small percentage 
 of blown petroleum asphalt or fatty-acid pitch. Fatty-acid pitches, 
 which have been overheated in the course of manufacture and have 
 thus lost their more volatile constituents, and become partly poly- 
 merised, are particularly useful in the preparation of black japans, 
 even to the extent of being used without further admixture. 
 
 Bituminous materials for use in the manufacture of japans 
 must fulfil the following requirements : | 
 
 1. They must be homogeneous and free from mineral matter, 
 particularly any of a gritty nature. 
 
 2. They should be opaque and have a black streak. 
 
 3. They should possess a distinct conchoidal fracture and 
 brilliant lustre, should not flow or lose their shape and should 
 retain sharpness of angles even when immersed in boiling water. 
 
 4, They must not separate, curdle or gelatinise on thinning 
 with petroleum naphtha. 
 
 5. They must bake in a reasonable time to a tough, per- 
 manently glossy coating without shrivelling or “ crazing.” 
 
 Gilsonite and such glance pitches as manjak will blend with fatty- 
 acid pitch, and the resulting mixture can be thinned with petroleum 
 naphtha to brushing consistency. But a tougher and more elastic — 
 japan may be prepared by incorporating a proportion of thickened 
 linseed oil, and incidentally the gloss is improved. Semi-drying oils, 
 which will oxidise to tough coatings at elevated temperature, may be 
 substituted for linseed oil, especially if boiled and combined with 
 driers. z: 
 
 _ Semi-glossy and flat black japans are prepared by grinding 
 carbon black into the foregoing mixtures; the resulting baked 
 surface then has an appearance resembling hard rubber. 
 
 Japans are applied to surfaces by dipping, spraying, flowing or 
 
Bituminous Paints, Varnishes, Enamels and Japans 157 
 
 brushing, and where only a thin coating is required probably a 
 mechanically-operated spraying appliance yields a more uniform 
 surface than results from brushing. The coated surface is then 
 heated in special japanning or stoving ovens for 1—4 hours at a 
 temperature of 95—220°C., depending on the composition of the 
 japan and the nature of the material being coated. Generally 
 wooden and similarly slightly porous articles require more baking 
 than metals, and modern practice resorts more to higher temperatures 
 for shorter periods of time than to the converse. 
 
 As japans do not invariably possess a great degree of elasticity 
 or weather resistance, the practice is resorted to of coating them 
 with a suitable finishing varnish, as in coach japans, but generally 
 it may be said that a baked japan forms a harder, tougher, and more 
 weather-resistant coating than that of a bituminous varnish left 
 to air-dry at room temperature. 
 
 The art of the varnish-maker consists in the preparation of a 
 japan of great depth and intensity of colour without employing so 
 high a proportion of pitch or suitable bituminous material that 
 solubility of the latter in the resultant coat takes place, a condition 
 manifesting itself, as Morrell 2°8 indicates, by the appearance on the 
 finished work of an undesirable greenish fluorescence—the “ green- 
 ing ” of the japan. 
 
 As Morrell 2° also points out, the shade is difficult to control : 
 some japans yield a chestnut-black coloured film, due to the variety 
 of pitch used. The latter should be as free as possible from volatile 
 bodies likely to interfere with the lustre and to leave the film tacky. 
 The coating should stand polishing the day following application. 
 The following formule are quoted by Morrell?°8 as being very roughly 
 representative : 
 
 1. 2. 
 RN PIT es kd unaxs Glyde ke sade cha dveSesadesphe es 25 20 
 Natural or petroleum asphalt ............... 8-4 20 
 DEUEMMIDS oe 4 5 hc ogre tenged cas save vers ss4cebesses 16-8 20 
 PIMPLE Yada we sings ie vebcing poh 00 Wake vad seas’ 49-8 20 
 
 _ Attempts have been made to introduce aniline blacks in place 
 of pitches to produce a more intense black, but the addition appears 
 only to impair the drying power of the film. 
 
 Some japans consist of a bituminous base with boiled oil and a 
 petroleum thinner, and thus approximate to the ordinary air-drying 
 Brunswick-black type of varnish. 
 
 A type of japan termed a Black Stoving Enamel is prepared by 
 incorporating a considerable amount of drying oil with the solid 
 bituminous base, and is used for insulating armatures and field coils 
 
158 Blacks and Pitches 
 
 of motors and dynamos. The armatures or coils are thoroughly 
 dried in a suitable oven to remove all traces of moisture, and then 
 dipped whilst hot into the cold japan, and subsequently baked for 
 8—12 hours, or even up to 24 hours, at about 85—95°C. The 
 resulting hard-baked bituminous japan protects the cotton or other 
 fibrous insulation wrapped round the coils from moisture and 
 chemical fumes, and if properly prepared and baked will withstand 
 currents of extremely high voltage. Such baking or stoving varnishes 
 must not soften when applied to armatures, and to prevent brittle- 
 ness, which would have a deleterious effect, it is advisable not to 
 incorporate resin with the japan, owing to the pea: of resin to 
 impart brittleness. 
 
 In search of the best type of coating for iron vos used to 
 hold acid plating solutions, Andés 214 found an enamel varnish 
 somewhat similar to a japan by reason of composition and method 
 of preparation the most suitable on account of its elasticity, its 
 behaviour in the bending test and resistance to blows. This asphalt 
 stove varnish was made from gilsonite, a thickened linseed oil 
 (stand oil) and tar. After application to the metal surface, the 
 varnishes were stoved at from 100 to 135° C., a second coat being 
 subsequently applied and dried in the same manner. 
 
 One of the defects to be countered in the preparation of baking 
 japans is that of ‘‘ pitting,’ and a variety of causes may operate 
 to bring about this objectionable feature. H. Gardner and P. 
 Holdt,?1 in a review of the causes of this trouble, submit a number 
 of important points as follow : 
 
 Oils free from “‘ foots ”’ should be used; the bituminous materials 
 selected must be free from mineral matter, and greasy, improperly 
 ground carbon blacks, where pigments are required, should be 
 avoided, whilst petroleum thinners of high boiling range and con- 
 taining large amounts of non-volatile residues may be responsible 
 for pitting and contraction of films. . 
 
 Lack of cleanliness in the kettles and the containers for the 
 japans—i.e., contamination by residues of polymerised oils and 
 various forms of varnish—must be avoided. The thinners to be 
 used should be added slowly, otherwise separation of some com- 
 ponents of the japans may occur, which are difficult to redissolve. 
 
 It is also recommended that surfaces to be japanned be free 
 from grease and be chemically clean, in order to inhibit an unsatis- 
 factory flow, and the japan should be applied warm to warm metal, 
 the temperature in the japanning oven being raised gradually after 
 the freshly-japanned articles have been placed therein. 
 
Bituminous Paints, Varnishes, Enamels and Japans 159 
 
 The British Thomson Houston Co.?!6 claim that a black japan 
 can be made with water thinners by incorporating 5 gallons of japan 
 base (asphaltic base and a drying oil) with 10 gallons of water 
 containing half a gallon of ammonia solution (s.g. 0-9) and 10—20% 
 by volume of a 20% solution of glue. Another proposal of a similar 
 character involves the preparation of an emulsion of an asphalt 
 oil base in water and the deposition of this base on the metal by 
 means of an electric potential difference maintained in the bath 
 containing the emulsion; the object to be japanned is made the 
 anode, and if large should be pre-heated before immersion in the bath. 
 Since the japan is deposited free from solvent, there is no resultant 
 drip on conveying the japanned object to the baking oven.??’ 
 
 More recently details are to hand of another method of making 
 a japan in water solution.?!§ 
 
 Avw-drying Black Enamels. 
 
 These are made in a manner analogous to that adopted for 
 black japans, but materials of less carefully selected quality are 
 chosen. Some contain only a pitch, boiled oil, and turpentine, and 
 are of the Brunswick-black type, for which Morrell? quotes the 
 following representative formule : 
 
 (a) 45 lbs. of pitch, 6 gallons of boiled oil, and 6 lbs. of litharge, 
 boiled until stringy and then cooled and thinned with 25 gallons 
 of turpentine. 
 
 (b) 32 lbs. of gilsonite, 14 gallons of boiled oil, and 54 gallons 
 of turpentine. 
 
 A quick air-drying black varnish for all sorts of iron work can 
 be made by melting 28 lbs. of coal-tar pitch with 28 lbs. of a 
 petroleum asphalt, and boiling for 8 hours, with subsequent addition 
 of 8 gallons of boiled oil, which is incorporated by heat. After 
 adding 10 lbs. of litharge and 10 lbs. of red lead, the mixture is 
 boiled until the mass will set hard between the fingers. On cooling, 
 the mixture is thinned with 20 gallons of turpentine. The varnish 
 will dry in 1—2 hours. According to Morrell,2°® the addition of 
 small quantities of coal-tar spirit (cresylic acid) improves the solu- 
 bility of the components of these black varnishes, but diminishes their 
 drying power, and therefore is restricted to stoving black enamels. 
 
 Some idea of the requirements to be fulfilled by air-drying 
 black enamels may be gathered from following British specifications 
 extracted by permission of the British Engineering Standards 
 Association from their Reports Nos. 2X. 9, and 2 X. 10, respec- 
 
160 Blacks and Pitches 
 
 tively, of Dec. 1920, official copies of which can be obtained from the 
 Secretary of the Association, 28 Victoria Street, Westminster 
 S.W.1, price 2d. each, post free. 
 
 BRITISH ENGINEERING STANDARDS ASSOCIATION 
 British Standard Specification for Aircraft Material. 
 
 UnDERCOATING BirumiINous Paint. (2 X. 9, 1920.) 
 
 1. Description.—The paint shall consist of a solution of high 
 grade bitumen, and in addition to satisfying the clauses of this Speci- 
 fication, shall comply with the special requirements of Appendix II. 
 
 2. Consistency.—The paint shall be of such a consistency as will 
 allow of easy application by brush or spray. 
 
 3. Rate of Drying—The paint, when applied to a hard wood, 
 shall dry at 70° F. (21° C.) in not more than 6 hours, to a glossy, 
 smooth, hard surface, which does not become soft or tacky when 
 the temperature is raised to 100° F. (38° C.). 
 
 4. Klasticity—The film of the paint shall be tested for elasticity 
 in accordance with Appendix I. 
 
 APPENDIX I. 
 
 Test for Elasticity. 
 
 The paint shall be applied to a panel of 30 S.W.G. tinned iron 
 and allowed to dry in a nearly vertical position for 24 hours at 70° F. 
 (21° C.). The panel shall be bent rapidly double over a } in. dia- 
 meter rod and straightened out again. The paint film shall show 
 no sign of cracking at the point of bending. 
 
 Apprnprix II. 
 
 Special Test for Bituminous Paint. 
 
 Two coats of the paint shall be applied to a wood panel, and 
 after remaining 16 hours in bright daylight, a coat of Wood Oil 
 paint (B.S. Specification X. 16) shall be applied. The film of paint 
 shall become dry after not more than 8 hours, and shall adhere to 
 the bituminous undercoating. 
 
 BRITISH ENGINEERING STANDARDS ASSOCIATION 
 British Standard Specification for Aircraft Material. i 
 
 Arr Dryina Buack Enamet. (2 X. 10, 1920.) 
 
 (NoTtE.—This material is to be used only for touching up Metal 
 parts.) 
 
 1. Description—The enamel shall be suitable for direct applica- 
 tion by brush or spray. A single coat shall produce a complete 
 covering. 
 
Bituminous Paints, Varnishes, Enamels and Japans 161 
 
 2. Rate of Drying.—The enamel when applied to a metal surface 
 ‘shall dry at 70° F. (21° C.) in not more than 8 hours to a smooth 
 glossy film. 
 
 3. Hlasticity and Adhesion.—The film of the enamel shall be 
 tested for elasticity and adhesion in accordance with Appendix I. 
 
 APPENDIX I. 
 Test for Elasticity and Adhesion. 
 
 The enamel shall be applied to a panel of 30 S.W.G. tinned iron 
 and allowed to dry in a nearly vertical position for 48 hours at 
 70° F. (21°C.). The panel shall be bent rapidly double over a 
 4 in. diameter rod and straightened out again. The enamel film 
 shall show no signs of cracking at the point of bending and shall 
 adhere to the metal surface. 
 
 _A United States specification 2!9 for a similar asphalt varnish 
 is more detailed : 
 
 The varnish shall be composed of a high grade of asphalt, fluxed 
 and blended with properly treated drying oils and thinned to the 
 proper consistency with a volatile solvent. It must be resistant 
 to air, light, lubricating oil, water and mineral acids of the concen- 
 tration hereinafter specified, and must meet the following require- 
 ments : 
 
 Appearance.—Smooth and homogeneous; no livering or 
 stringiness. 
 
 Colour.—Jet black. 
 
 Flash Point (closed cup).—Not below 30° C. (86° F.). 
 
 Action with Linseed O1l.— Varnish must mix freely to a homo- 
 geneous mixture with an equal volume of raw linseed oil. 
 
 Insoluble in Carbon Disulphide—Not more than 1%. 
 
 Non-volatile Matier.—Not less than 40% by weight. 
 
 Fatty Matter.—Not less than 20% of the non-volatile. Must 
 be liquid and not show any rosin by the Liebermann—Storch 
 test. 
 
 Set to Touch.—Within 5 hours. 
 
 Dry Hard and Tough.—Within 24 hours. 
 
 Toughness.—Film on metal must withstand rapid bending 
 over a rod 3 mm. ( in.) in diameter. 
 
 Working Properties—Varnish must have good brushing, 
 flowing, covering and levelling properties. 
 
 Resistance to Water.—Dried film must withstand cold water 
 
 for 18 hours. 
 11 
 
162 Blacks and Pitches 
 
 Resistance to Oil.—Dried film must withstand lubricating oil 
 for 6 hours. 
 
 Resistance to Mineral Acid.—Dried film must withstand 
 action of the following acids for 6 hours: sulphuric acid, 
 s.g. 1:3 (about 40% H,SO,); nitric acid, s.g. 1-22 (about 35% 
 HNO); hydrochloric acid, s.g. 1-09 (about 18% HCl). 
 
 The original specification must be consulted for details as to 
 the carrying out of these tests. Evidently the specification corre- 
 sponds to that of an air-drying black enamel. 
 
 Various air-drying black enamels and varnishes are in use, 
 their composition being suited somewhat to their uses and require- 
 ments. Such materials as Mexphalte, Patagonian asphaltum, 
 Syrian asphaltum, etc., can be used without the addition of oils 
 or driers. The asphaltum is melted slightly, then thinned down 
 with 1—14 times its weight of white petroleum spirit, turpentine 
 or even coal-tar naphtha to brushing consistency. The resulting 
 enamel dries in about an hour to a fine varnish-like gloss, which. 
 it retains. These enamels form excellent coatings for all classes 
 of outside iron and steelwork, for fire grates and fenders, iron pipes, 
 
 te., being not only water-proof and rust-preventing, but non-con- 
 
 ducting and insulating. The rapidity with which these black 
 varnishes dry depends mainly on the volatility of the thinner used 
 in their manufacture. 
 
 Insulating Varnishes. 
 
 Owing to their high dielectric constants, pitches are valuable 
 insulating materials, and a solution of the pitch with gum or resin 
 in a suitable thinner is allowed to impregnate the insulating 
 material—paper, silk, cotton, etc.—and after volatilisation of the 
 solvent, a film of non-conducting and moisture-resisting material 
 is left. The varnish should have great penetrating power, and 
 the dried film should be sufficiently elastic to withstand the strain 
 due to bending and to temperature changes. 
 
 The functions of insulating varnishes are summarised by 
 Morrell 2°8 as follows : 
 
 1. To provide a waterproof coating with sufficient elasticity 
 to withstand the movement between parts produced either by 
 rotation or by magnetic or electric forces. 
 
 2. To increase the insulating properties of the impregnated 
 material. 
 
 3. To protect the parts from the action of oils and acids. 
 
Bituminous Painis, Varnishes, Enamels and Japans 163 
 
 4. To prevent excessive rise in temperature through their 
 relatively high thermal conductivity. 
 
 Insulating materials for treating paper and fabrics, and solid 
 impregnating compounds have been dealt with in the previous 
 chapter. Morrell 2°§ quotes the following as typical of oil and 
 pitch insulating varnishes for impregnating windings : 
 
 Stoving Black Insulating Varnish. 
 
 300 parts of thickened linseed oil 
 100 ,,  ,, petroleum residual pitch 
 7. (i045), Suiphor 
 ie ee »» litharge 
 1 part of manganese dioxide 
 100 parts of turpentine 
 400 ,,  ,, light petroleum spirit 
 
 The conditions governing chemical action in high-voltage wind- 
 ings are given by Fleming and Johnson,?*° who state that chemical 
 action occurs only where air pockets are present due to imper- 
 fections in the windings, and then only when the voltage across 
 them is high enough to produce a discharge. Oxidation then 
 occurs in the air gap discharge, the effect on oils and gums being 
 to produce organic acids, but asphalts and pitches are attacked only 
 slightly, and paraffin wax not at all. The organic acids produced 
 act in a strongly disintegrating manner on the varnish material. 
 
 In a review of the chemical problems arising in connection with 
 insulating varnishes, H. C. P. Weber #2! mentions that varnishes 
 give rise to acidic oxidation products (cf. volatile fatty acids) of 
 low resistance, though this behaviour is not marked in the case of 
 asphaltic varnishes. For impregnating, the penetration depends 
 on the viscosity, body, and colloidal nature of the varnish—for 
 binding, the strength and rigidity are important factors. 
 
 REFERENCES. 
 
 210 Paint Manufacturers’ Assoc. of U.S., Circular No. 202, 1924, pp. 302- 
 327. 211 ** Enamels,’ Chemistry and Industry, 1925, p. 25. 712 J. Ind. 
 Eng. Chem., 1924, 16, 509. 213 J. Soc. Chem. Ind., 1924, 48, 1797. 214 Farb. 
 Zeitung, 1923, 1260. 215 Circular 145, Educational Bureau Scientific Section 
 Paint Manufacturers’ Assoc. of U. S. .. Feb., 1922. 216 British Thomson 
 Houston Co., English Patent 155,427 of 1919. 217 Chem. Trades Journ., 
 1920, May 15th. #18 W. P. Davey and General Electric Co., U.S. Patent 
 1,472,716 of 1923. 219 Circular No. 104, Bureau of Standards, U. S.A., 1920. 
 220 Fleming and Johnson, Journ. Inst. Elect. Eng., 47, No. 209. 221 Ind, 
 Hing. Chem., 1925, 17, 11. 
 
 Bibliography. 
 S. H. Gilson, U.S. Patents 361,759, 362,076 and 415,864. R. 8S. Morrell 
 
 and A. de Waele, ‘‘ Rubber, Resins, Paints and Varnishes,’’ 1921. A. R. 
 Matthis, ‘‘ Les Vernis Isolants en Electrotechnique,”’ 1921. 
 11* 
 
CHAPTER XXI 
 BITUMINOUS PAVING MATERIALS 
 
 Roadway and Pavement Construction—Surface Phenomena in connection 
 with Asphalt Pavement Construction—The British Standard Specification 
 for Tar and Pitch for Road Purposes. 
 
 As we have already noted in Chapter IX, the first asphalt block pave- 
 ment of which any record is now extant was laid down by Nabo- 
 polassar (625—604 B.c.), the father of Nebuchadnezzar, but apparently 
 the art was lost to mankind, for it was not until 1836 that asphalt 
 was first used in London for foot pavements and in the United 
 States in 1838, Seyssel asphalt from the Rhone Valley in France 
 being the material employed. Later on we find asphalt roadways 
 being constructed and Trinidad asphalt the material selected. 
 
 At the present day bituminous materials for constructing pave- 
 ments, coating the surface of macadam, or for use merely as a means 
 of dust-laying are finding increasing world-wide use, and all or any 
 of the following materials, either singly or in combination, may be 
 used, according to circumstances : native asphalts, residual asphalts, 
 blown petroleum asphalts, asphaltites and the various tars and 
 pitches, such as those derived from gas- and coke-oven works. 
 Native asphalts are, however, the most used, and in 1921 the esti- 
 mated annual consumption (world’s) for paving was 669,000 tons. 
 
 It is not possible to dwell here on more than one or two interest- 
 ing aspects of a study which rightly belongs to the domain of High- 
 way and Pavement Engineering and Construction. It has been 
 suggested, however, in certain quarters that asphalt is unsuitable 
 for roadway construction on account of its tendency to yield a 
 slippery surface. As the causes which produce this effect are known, 
 their elimination is possible by suitable technical control, and it 
 is worthy of note that out of 140 miles of arterial roads around 
 London only some 20 miles are made with a concrete surface—the 
 rest have an asphalt surface. At the present day, an elastic or 
 resilient surface is considered as the ultimate solution of the road 
 problem, this being the only surface capable of withstanding the 
 pounding action of modern traffic with its heavy loads and high 
 speeds.2#2, In this respect, bitumen, according to its advocates, 
 stands unchallenged—it offers great resistance to the effects of 
 dampness and retains its smoothness of surface for many years. 
 
 Undoubtedly, the peculiar properties of Trinidad asphalt are 
 due to the colloidal suspension of clay present. This is not deposited 
 from solutions of the bitumen, even after standing for years. It is 
 
 owing to the presence of this colloidal clay, together with sulphur 
 164 
 
Bituminous Paving Materials 165 
 
 derivatives in the Trinidad asphalt, and to the sulphur derivatives 
 in Bermudez asphalt, that these materials are so desirable in road- 
 way construction, for asphalt serves the purpose of cementing 
 together the mineral aggregates and sands used in laying the different 
 types of pavements and road surfaces. It is worthy of note that 
 the Thames Embankment is a type of Trinidad sheet asphalt pave- 
 ment laid on old macadam and Trinidad asphalt concrete. 
 
 The surface of an asphalt pavement being an agglomeration of 
 sand graded in size with a fine mineral dust and a bitumen in the 
 form of asphalt of approved consistency, C. Richardson *?° regards 
 the asphalt pavement as a heterogeneous system of two components, 
 one a solid (the mineral aggregate) and the other a liquid (the 
 bitumen). 
 
 The importance of surface phenomena and the relationship of 
 solids in colloidal suspension to the liquids with which they are 
 associated is definitely recognised in this connection, and has led to 
 investigations on the properties of mixtures of colloidal clay and 
 petroleum residual pitches with a view to their use in pavement 
 construction. This aspect of the subject opens up a very fruitful 
 field for investigation. 
 
 Already much work has been done in this direction in the manu- 
 facture of bituminous emulsions, and amongst the materials which 
 have been used to form emulsions of the dust-laying oils and the 
 more solid and semi-solid bitumens may be mentioned: soaps, those 
 consisting largely of ammonium oleate being the most favoured; the 
 alkalies, when used with tars and pitches, containing phenolic 
 bodies; colloidal clays and mineral matters; small amounts of 
 colloidal vegetable substances such as the saponins and vegetable 
 mucilages. 
 
 In the typical sheet asphalt roadway we have the following to 
 consider in brief outline : 
 
 1. The Foundation or Base Course. 
 
 This may consist of a brick or block roadway and some- 
 times even of old macadam, but the most satisfactory foundation 
 is probably 4 to 9 ins. thick of Portland cement concrete. 
 
 2. The Intermediate or Binder Course. 
 
 This may be either graded or ungraded coarse-aggregate 
 bituminous concrete; broken stone is used, and this may be 
 limestone or granite, and asphaltic sine 
 
 3. Surface or Wearing Course. 
 
 This is composed of graded sand and an asphaltic cement. 
 
166 Blacks and Pitches 
 
 Typical asphaltic cements prepared from Trinidad and Bermudez 
 asphalts respectively test as follows : 
 
 
 
 From From 
 Trinidad Bermudez 
 asphalt. asphalt. 
 
 (Test 7) Specific gravity at 77°F. ...........08.- 1-26 1:07 
 (Test 9b) Penetration at 77° BF. wo... .cccescseeeeeees 65 65 
 (Teast 9c) Consistency at 27°22. o.ssncineantnenponnts 7:9 8-0 
 (Tést 100) Ductility at 777 oy. cra ccceesenese 21:5 17 
 (Test 15c) Fusing point (cube method) ............ 148° F. 150° F. 
 (Test 16a) Volatile matter at 325° F. in 5 hrs. ...... 2:°5% 32% . 
 (Test 19): “Pixon Carbon o..scccss-seascredccecs uececee 6-1% 9-8% 
 (Test 21a) Soluble in carbon disulphide ............ 65:7% 97-6% 
 (Test 21c) Mineral matter ...,.......ccccccssescocsceees 29'5% 0:3% 
 
 From a chemical point of view we have already (Chapter XII) 
 seen that all the more or less solid bitumens consist of “‘ asphaltenes ”’ 
 which impart cohesiveness and supply body and stability, whilst 
 the “ petrolenes ”’ are extremely sticky and of cement-like nature. 
 A solid asphalt cement should contain not less than 15% of 
 ‘‘ asphaltenes ”’ and not less than 70% of “ petrolenes ” to have the 
 proper degree of stability and adhesiveness; the “ petrolene ’”? must 
 be sufficiently sticky, otherwise the asphalt may not be suited as a 
 cement. | 
 
 H. Tindale 1° considers that the ‘‘ asphaltenes ” in road tars are 
 their most desirable constituents, and if this contention be correct, 
 it supplies additional confirmation of the fact that prepared hori- 
 zontal retort tars are much more useful as road tars than those 
 prepared from vertical retort tars, for the reasons already indicated 
 by Wright,}°* viz., horizontal retort tars are less paraffinoid. 
 
 The requirements of British Standard Specifications of Tars, Pitches, 
 Bitumens and Asphalts when used for road purposes may be gathered from 
 the following, extracted by permission of the British Engineering Standards 
 Association from their Report No. 76, 1916, official copies of which can be 
 
 obtained from the Secretary of the Association, 28, Victoria Street, West- 
 minster, §.W. 1, price ls. 2d. each, post free. 
 
 BRITISH ENGINEERING STANDARDS. ASSOCIATION. 
 
 British STANDARD NOMENCLATURE OF 
 TARS, PITCHES, BITUMENS AND ASPHALTS 
 WHEN USED FOR ROAD PURPOSES. 
 
 _ IntrRopuctTorRY REMARKS. 
 
 The materials now used by Road Engineers for binding together the 
 stones and other mineral aggregate used to form road crusts and road surfaces 
 may be conveniently divided into three groups. These are :— 
 
Bituminous Paving Materials 167 
 
 1. The tars and pitches obtained by the destructive distillation of 
 coal or similar substances. 
 
 2. The bitumens and asphalts which are found in nature, or are 
 obtained artificially from asphaltic oils. 
 
 3. Chemical binders, including the Portland and natural cements 
 which owe their cementing value as road binders to chemical action, and 
 which are not dealt with in the present report. 
 
 Hitherto the term ‘“‘ bituminous material’ has been loosely applied to 
 tar products as well as to bitumens and asphalts, but the Committee have 
 from the first considered that it was desirable from the Road Engineers’ 
 point of view to maintain a sharp line of demarcation between the two groups. 
 The views put forward in correspondence from America and by American 
 engineers of standing and experience have been carefully considered, but the 
 Committee still adhere strongly to the view that the description ‘‘ bituminous ”’ 
 should be applied only to the second group. 
 
 In this country the first group of road binders, the coal tars and pitches, 
 have been in use for many years, and as the Road Board in 1911 issued 
 Specifications for the tars, tar oils and pitches, which they recommended 
 for road purposes, these materials have already to some extent been defined 
 by those Specifications. The Road Board early in 1914 issued a second 
 edition of these Specifications. Only two classes of tar, and one class of 
 pitch are dealt with, and as these Specifications are of such recent date, the 
 Committee recommend that they be adopted provisionally as the British 
 Standard Specifications for Tars and Pitches used for Road Work. 
 
 The Committee find that the choice of names for the second group of road 
 binders is a matter of some difficulty. This difficulty is increased by the 
 fact that whilst it is desirable to obtain the concurrence of the American 
 Engineers to the nomenclature and definitions which the Committee now 
 propose, the adoption of the American nomenclature for the various materials 
 composing this group would be liable to lead to confusion and misunder- 
 standing in this country. 
 
 The Committee have been very anxious to secure uniformity with American 
 practice, and have carefully and fully considered the definitions adopted by 
 the American Society for Testing Materials and by the Committee of the 
 American Society of Civil Engineers, put forward by the American corre- 
 sponding members, but it is felt that the definitions now decided on are 
 preferable from the Road Engineers’ point of view, as they are based on those 
 characteristics of the materials which can be most readily verified when 
 employed for road making. 
 
 In accordance with this view, the Committee consider that it is desirable 
 to make a sharp distinction between coal-tar and paraffin-oil derivatives on 
 the one side, and native bituminous substances and asphaltic oil residues 
 on the other, and they are therefore unable to accept the American definition 
 of Bitumen which would include the coal tars. 
 
 DEFINITIONS. 
 First GROUP. 
 TAR PRODUCTS (PRINCIPALLY COAL TAR AND PITCH). 
 
 Definition of Tar. 
 1. Tar is the matter (freed from water) condensed from the volatile 
 products of the destructive distillation of hydro-carbon matter, whether 
 this be contained in coal, wood, peat, oil, etc. 
 
 Prefix denoting source of origin or method of production. 
 2. A prefix such as ‘‘ Coal,”’ ‘‘ Wood,” “* Peat,’ “‘ Gas Works,” “ Blast 
 Furnace,” “‘ Coke Oven,”’ etc., must be added to the word ‘‘ Tar ’’ to indicate 
 the source of origin or method of production. 
 
168 Blacks and Pitches 
 
 Definition of Pitch. 
 3. Pitch is the solid or semi-solid residue from the partial evaporation 
 of tar. 
 
 SECOND GROUP. 
 
 BITUMENS AND ASPHALTS. 
 
 Definition of Bitumen. 
 
 4. Bitumen is a generic term for a group of hydro-carbon products soluble 
 in carbon disulphide, which either occur in nature or are obtained by the 
 evaporation of asphaltic oils. The term shall not include residues from 
 paraffin oils or coal-tar products. 
 
 Nore.—Commercial materials may be described as BrTuMEN if they 
 contain not less than 98 per cent. of pure Bitumen as defined above. 
 
 Definition of Native Bitumen. 
 5. Native Bitumen is bitumen found in nature, carrying in suspension 
 @ variable proportion of mineral matter. 
 The term “‘ Native Bitumen” shall not be applied to the residuals from 
 the distillation of asphaltic oils. 
 
 Definition of Asphalt. 
 
 6. Asphalt is a road material consisting of a mixture of bitumen and 
 finely graded mineral matter. The mineral matter may range from an 
 impalpable powder up to material of such a size as will pass through a sieve 
 having square holes of } inch side. 
 
 Definition of Native or Rock Asphalt. 
 
 7. Native or Rock Asphalt is a rock which has been impregnated by 
 nature with bitumen. 
 
 Prefixes denoting Source of Origin. 
 
 8. The Committee recommend that for convenience of identification 
 prefixes denoting geographically the source of origin should be attached to 
 each of the four terms defined above. 
 
 BRITISH STANDARD SPECIFICATION FOR 
 PITCH FOR ROAD PURPOSES. 
 
 (Based upon the Road Board Specification No. 6 and published with the approval 
 of the Road Board.) , 
 
 Standard Pitch for Road Purposes in the United Kingdom shall be 
 specified as under :— 
 
 BRITISH STANDARD SPECIFICATION FOR PIrcH. 
 
 General. 
 
 1. This pitch is suitable for pitch-grouting. See ‘‘ Road Board General 
 Directions for Pitch-Grouting.”’ 
 
 a 
 
 Consistency. 
 
 2. The pitch is obtained of the required consistency most conveniently 
 by running it off from tar stills in which the distillation of the tar has been 
 stopped at the point at which the residual pitch will give a penetration of 
 70 (or such other penetration as may be specified to suit climatic or local 
 conditions) when tested at 25° Centigrade (77° Fahrenheit) on a penetro- 
 meter. Harder pitch may be softened or cut back, in the still or in a mixer 
 at the tar works, to the extent necessary for it to give this penetration, by 
 the addition of tar oil of the grade specified below in Clauses 7 to 10. 
 
Bituminous Paving Materials 169 
 
 Where pitch of the required consistency is not thus directly procurable, 
 it may be prepared by softening commercial soft pitch, as specified below 
 in Clauses 4 to 6, by the addition of tar oil as specified below in Clauses 7 to 
 10. In preparing the softened pitch in this manner the tar oil is added to 
 the pitch in the manner described under ‘“‘ Instructions for Melting the Pitch ”’ 
 in the ‘‘ Road Board General Directions for Surfacing with Pitch-Grouted 
 Macadam,”’ in such proportions that the resultant softened pitch will give a 
 penetration of 70 (or such other penetration as may be specified to suit 
 climatic or local conditions) when tested at 25° Centigrade (77° Fahrenheit) 
 on a > penser with a No. 2 needle weighted to 100 grammes for five 
 seconds. 
 
 PREPARED PircH FROM TAR DISTILLERIES. 
 General Characteristics. 
 
 3. Pitch which has been procured of the required consistency directly 
 from a tar distillery needs only to be thoroughly melted in the pitch heaters 
 or boilers, but as a precaution against burning, | to 2 per cent. of tar oil may 
 advantageously be put into the boilers with the pitch. 
 
 Pitch which has been procured of the required consistency directly from 
 a tar distillery shall not yield more than 4 per cent. of distillate below 270° 
 Centigrade, or 518° Fahrenheit, on distillation as described below in Clause 5, 
 and shall contain not less than 16 per cent. and not more than 28 per cent. 
 of ‘‘ free carbon,’’ as defined below in Clause 6. 
 
 COMMERCIAL Sort PITcH. 
 
 Source of Pitch. 
 
 4. The pitch shall be derived wholly from tar produced in the carboniza- 
 tion of coal, except that it may contain not more than 25 per cent. of-pitch 
 derived from tar produced in the manufacture of carburetted water gas. 
 
 Fractionation. 
 
 5. On distillation in a litre fractionating flask (a distillation flask without 
 special fractionating column) one-half to two-thirds filled, the pitch shall 
 yield the proportions by weight of distillates stated below; the temperatures 
 of distillation being read on a thermometer of which the bulb is opposite 
 the side tube of the flask :— 
 
 Below 270° Centigrade or 518° Fahrenheit, not more than 1 per cent. 
 of distillate. 
 
 Between 270° and 315° Centigrade or 518° and 599° Fahrenheit, 
 not less than 2 per cent. and not more than 5 per cent. of distillate. 
 
 Free Carbon. 
 
 6. The pitch shall contain not less than 18 per cent. and not more than 
 31 per cent. by weight of free carbon. The free carbon is to be determined 
 by the weight of the residue after complete extraction of all matter soluble 
 in benzol or disulphide of carbon. The extraction is best carried out in a 
 Soxhlet or similar apparatus by disulphide of carbon followed by benzol. 
 
 TaR OIL. 
 Source of Tar Oil. 
 
 7. Tar oil to be used is preferably a filtered green or anthracene oil, and 
 shall be derived wholly from tar produced in the carbonization of coal or 
 from such tar mixed with not more than 25 per cent. of its volume of tar 
 produced in the manufacture of carburetted water gas. 
 
 Specific Gravity. 
 8. The specific gravity of the tar oil at 20° Centigrade (68° Fahrenheit) 
 shall lie between 1-065 and 1-085. 
 
170 Blacks and Pitches 
 
 Freedom from Naphthalene and Anthracene. 
 
 9. The tar oil after standing for half an hour at 20° Centigrade (68° Fah- 
 renheit) shall remain clear and free from solid matter (naphthalene, anthracene, 
 etc.). 
 
 Fractionation. 
 
 10. The tar oil shall be commercially free from light oils and water. On 
 distillation in a litre fractionating flask (a distillation flask without special 
 fractionating column) one-half to two-thirds filled, the tar oil shall yield the 
 proportions by weight of distillates stated below; the temperatures of dis- 
 tillation being read on a thermometer of which the bulb is opposite the side 
 tube of the flask :— , 
 
 Below 170° Centigrade or 338° Fahrenheit, not more than 1 per cent. 
 of distillate (light oils and water, if any). 
 
 Below 270° Centigrade or 518° Fahrenheit, not more than 30 per cent. 
 of distillate (middle oils, and light oils and water, if any). 
 
 Below 330° Centigrade or 626° Fahrenheit, not less than 95 per cent. 
 of distillate (heavy oils, middle oils, and light oils and water, if any). 
 
 REFERENCES. 
 
 222 Sir Courtauld Thomson, reported in The Chemical Age, April 4th, 
 1925, p. 329. 2% “*The Colloidal State of Matter in its Relation to the 
 Asphalt Paving Industry,” 1917. 
 
 Bibliography. 
 
 ‘* Manufacture of Bituminous Road-dressing Materials,’ J. A. Vielle, 
 Eng. Patent 196,950 of 1921. C. J. Cruijff, Eng. Patent 201,813 of 1922. 
 J. F. Wake and D. D. Spence, Eng. Patent 208,879 of 1922. FF. Morton, 
 Eng. Patent 194,448 of 1922. Highway Engineer’s Year Book, 1924, Sir 
 Isaac Pitman & Sons. ‘Streets, Roads and Pavements,’ by H. G. Whyatt, 
 Sir Isaac Pitman & Sons. ‘‘ General Directions and Specifications relating 
 to the Tar-Treatment of Roads,’ H.M. Stationery Office. 
 
APPENDIX I 
 
 THE following is reproduced by the courtesy of the Director of 
 the U.S. Geological Survey, Department of the Interior, Washington, 
 the information contained therein having only recently been made 
 available. 
 
 CARBON BLACK 
 PRODUCED: FROM NATURAL ee 
 IN 1923 
 
 By G. B. RICHARDSON 
 
 Mineral Resources of the United States, 1923—Part II 
 (Pages 89-90) 
 Published September 29, 1924 
 
 The production of carbon black from natural gas in the United 
 States in 1923 amounted to 138,262,648 lbs., an increase of 104% 
 over the production in 1922. The increase resulted from the 
 expansion of the industry that followed the greater demand in 
 1922 for carbon black by rubber companies. The number of pro- 
 ducers of carbon black reporting to the Survey increased from 26 
 in 1922 to 47 in 1923, and the number of plants operated from 43 to 
 69. The operations resulted in over-production during the later 
 part of 1923, as indicated by the quantity of stocks held in the 
 hands of producers. Stocks increased from 2,434,547 lbs. on 
 January 1, 1923, to 38,320,814 Ibs. on December 31. 
 
 The production by States in 1923 as compared with that in 1922 
 is shown in the following table. Louisiana led all the States in 
 the quantity of carbon black produced, as it has in the last three 
 years, and its output of more than 101,000,000 lbs. shows an increase 
 of 142% over its output in 1922. The production of Kentucky 
 in 1923 increased 134%. The production of West Virginia, on the | 
 other hand, declined slightly. Texas joined the States producing 
 carbon black in 1923. The production of Wyoming, Oklahoma, 
 Montana, and Pennsylvania, which ranked in the order named, is 
 grouped together to avoid revealing the operations of individual 
 
 companies. 
 171 
 
172 Blacks and Pitches 
 
 Carbon Black produced from Natural Gas in the United States 
 im 1922-23. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 Value at plant, a ix 
 State Producers| Number | Quantity honiene a yield per 
 >. reporting. | of plants. (Ibs.) Averane nedid Ci Me. ft. 
 Total, 8 (lbs.) 
 (cents.) c. ft.). 
 
 1922 | 
 Louisiana ,,.., seneed : 14 18 41,966,856 | $3,564,393 8-5 38,004,000 1-1 
 West Virginia ...... 11 18 20,095,481 | 1,714,576 85 12,087,000} 17 
 Kentucky  ....cs00 3 3 4,306,875 416,549 9-7 2,300,000 1:9 
 sas Kind ates ; : 
 
 YOMING ,..,...00006 - . : 
 Montana wa 1 1 1,425,917 124,100 87 1,238,000 1-2 
 Pennsylvania ..,... 1 1 
 
 vs a 26 43 67,795,129 | 5,819,618 8-6 53,629,000 1:3 
 Louisiana ............ 29 35 101,398,881 | 8,415,566 8-3 82,974,000 1.2 
 West Virginia ...... 11 20 20,038,415 | 1,983,385 9:9 13,722,000 1-5 
 Kentucky  .......0. 6 6 10,058,887 758,091 7-5 5,906,000 1-7 
 SE ORBS \ wactacasacnges 3 3 2,633,013 183,306 7-0 2,136,000 1:2 
 fe era bases 2 : 
 
 BhHoMa ...eaee 1 d ' 
 Montana ... 1 1 4,133,452 351,718 8:5 4,358,000 0-9 
 Pennsylvania ,..... | 1 1 
 
 138,262,648 | 11,692,066 85 109,096,000 | 1:3 
 
 
 
 
 
 : a In counting the total number of producers a producer operating in more than one State is counted 
 only once. 
 
 Summary of Statistics of Carbon Black from Natural Gas in 
 the United States, 1919-1923. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 1919. 1920. 1921. 
 Number Of producers ....csscccoscccssssecvee 17 19 23 47 
 Waumaber of Plants... .0rcocsrccseessenvesescecses 36 35 41 69 
 Quantity produced : 
 Louisiana ....cccccsccsssvesveececees LDS. | 14,024,606 | 18,565,498 | 31,003,615 | 41,966,856 | 101,398,881 
 West Virginia ...cccssscceeesee 99 | 29,925,614 | 26,659,469 | 25,073,000 | 20,095,481 | 20,038,415 
 Other Stshes ivcksssseselsaresschuss les 8,106,721 6,096,925 3,689,700 6,732,792 16,825,352 
 Total ....ccccosssscsccecsesesssceee gp | 52,056,941 | 51,321,892 | 59,766,315 | 67,795,129 | 138,262,648 
 Value at plants: 
 TOGA « . sincesseidavnmescpivcanzes COREE 3,816,040 | 4,032,286 | 5,445,878 | 5,819,618 | 11,692,066 
 Average per1b. .....cccccscreres CONES TB. 79 9-1 8-6 8-5 
 Estimated quantity of natural gas used, 
 srseecsseccevecneedd C. ft. | 49,896,000 | 40,599,000 | 50,565,000 | 53,629,000 | 109,096,000 
 Average yield per Mc. ft.  csececossese LDS. 1-0 1:3 1-2 1:3 1:3 
 
 
 
APPENDIX II 
 
 Messrs. SHELL-MEX LimiTEpD, London, through their Technical 
 Department, have kindly supplied a detailed table showing the 
 characteristics of their well-known grades of Mexphalte. This 
 table should be studied in conjunction with Chapter XIV, on 
 Petroleum Asphalts or Petroleum Residual Pitches: the manu- 
 script was in the press when the table was furnished to the author, 
 otherwise the information therein would have been incorporated in 
 the text of Chapter XIV. 
 
 Properties of Various Grades of Mexphalte. 
 
 
 
 wide 3 9 ce px 5B es B. 5 ag 4 66 mR. 1 ” “é R, 7) o> 
 
 
 
 
 
 Grade, Grade. Grade. Grade. Grade, Spramex. 
 
 Specific gravity at 
 
 BOOT iiss cedar sichins 1-035 1-036 1-041 1-039 1-038 1-028 
 flash point—Cleve- 
 
 ~, -Opeti'Oap © icc... over 500°F | over 500°F | over 500°F over 500°F | 224°C=4385°F | 232°0=450°R 
 
 Loss on heating, N.Y. 
 
 oven, 5 hrs, at 
 
 BA DT cnacecpunheners negligible negligible negligible negligible negligible 0:36% 
 Sal pe ® ccavidsscresy ons 5-8% 55% 5:5% 489 4:8% $55% 
 Asphaltenes ......s0000 261% 30:3% 37:8% 39-29% 36:5% 16:7% 
 Soluble in OS, ......006 99:8% 99:8% 99-7% 99-5% 99-6% 99-8% 
 Melting point 
 
 Th, iI.) eaves neque 55°C =131°F | 68°O=154°F | 112°C =234°F | 135°O=275°F | 97°C =207°F | 39-5°C=104°F 
 Melting point 
 Sr Bs) ccstsaree eves 40°C =104°F | 53°C=127°F | 97°C=207°F | 120°C =248°F | 82°C=180°F | 24:5°C=76°R 
 
 Conradson coking 
 
 POR chwsctavcsdeomases 25-4% 26:0% 88-5% 26:5% 256% 19% 
 Co-efficient of expan- 
 
 sion per °C. approx. 0-0006 0-0006 0-0006 0-0006 0-0006 0-0006 
 Penetration at 77°F 50 25 4 8 25 200 
 
 - Ductility at 77°F ... 120+ 10 nil 1 4 120+ 
 
 Dielectric strength 
 
 PNM. LAD. veessenee +. 35,000 volts} + 35,000 volts} +-35,000 volts | +35,000 volts | +35,000 volts | +35,000 volts 
 Ash (mineral) ......... 02% 02% 03% 0:2% 01% 02% 
 Volatile matter (Con- 
 
 radson values used) 746% 74% 61:5% 73-5% TA AY 81% 
 
 
 
 173 
 
APPENDIX III 
 
 THE statistics below have been kindly supplied to the author 
 by the Department of Overseas Trade, London, 8.W. 1. 
 
 Statement showing the imports, exports (domestic) and re-exports 
 of the undermentioned articles into and from the United 
 Kingdom during each of the years 1921, 1922 and 1923, and 
 January to November 1924, so far as possible. 
 
 
 
 
 
 
 
 IMPORTS. 1921. 1922. 1923. Jan. to Nov.: 1924. 
 
 
 
 
 
 
 
 
 Total imports of : Cwts. &. Owts. £. Owts. £. Cwts. &. 
 Oarbon blacks ...... 49,320 200,350 | 77,606 278,384 | 118,159 } 513,297 Not available. 
 Pitch: Tons. Tons. Tons. Tons, 
 
 ‘wea? 
 834 6,660 | 59,659 | 286,613] Not available. 
 4,231 | 40,969| 4,493 | 34,367 
 
 146,649 | 870,012 | 262,871 |1,464,321 | 256,076 | 1,827,995 
 
 EXPORTS (produce and manufactures of the United Kingdom). 
 
 Ooal-tar pitch......... 
 Other sorts ......0.. 
 Asphant and bitumen 
 
 568 5,226 
 5,746 | 114,391 
 92,903 | 788,126 
 
 Total exports of : Cwts. &. Owts. £. Owts. £ Owts. | &. 
 Carbon blacks ...... 4,239 14,413 5,707 15,717 8,939 30,530 Not available. 
 Pitch : Tons. Tons, Tons. Tons, &. 
 Coal-tar pitch ...... 304,235 {1,805,794 | 424,691 |1,543,291 | 414,224 |2,527,016 | 276,493 | 1,218,462 
 Other sorts  .......5. 1,190 24,978 4,154 45,566 13,130 | 100,869 Not available. 
 Asphalt and bitumen Not separately distinguished, 
 RE-EXPORTS (foreign and colonial merchandise). 
 Total re-exports of : Owts. &. Owts. &. Owts. &. 
 Carbon blacks ...... 775 4,792 1,201 5,081 6,807 34,346 Information 
 Pitch : Tons. Tons. Tons. not available. 
 Coal-tar pitch ...... 1 13 38 943 37 630 
 Other sorts ......66. 297 8,463 306 7,364 242 4,413 
 Asphalt and bitumen 4,850 52,570 3,578 30,908 7,194 47,820 
 
 
 
 Note.—As from the 1st April, 1923, the term ‘‘ United Kingdom ”’ refers to Great Britain and Northern 
 Ireland only. 
 
 174 
 
INDEX OF NAMES 
 
 ABRAHAM, H., 67, 68, 70, 71, 82, 83, 85— 
 87, 98-100, 102, 103, 107, 108, 110, 
 112, 119, 124, 125, 142, 143, 152 
 
 Acheson, E. G., 17, 18 
 
 Amer. Soc. Testing Materials, 83, 85, 87 
 
 Anderton, B. A., 138 
 
 Andés, L. E., 158 
 
 Bardwell, 94 
 
 Baskerville, 104 
 
 Becher, 67 
 
 Benson, H. K., 124 
 
 Bernstein, F., 126 
 
 Berthelot, 129 
 
 Blood, A. R., 31, 33 
 
 Blood, E. R., 31, 34 
 
 Bone, W. A., 29, 30, 113, 114 
 
 Bornstein, E., 126 
 
 Brit. Eng. Standards Assocn., 52, 53, 67, 
 159, 160, 166-170 
 
 Brockedon, 19 
 
 Brown, R. L., 78 
 
 Brownlee, R. H., 37 
 
 Burnice, H., 111 
 
 Butler, T. H., 114, 121 
 
 Byerley, F. X., 109 
 
 Cabot, G. L., 27, 31, 33, 35, 40, 42, 44 
 Cesalpinus, 19 
 Calbeck, 49 
 
 Campbell, A., 106, 107 
 Carmody, P., 94, 95 
 Cary-Curr, H. J., 89 
 Chambers, 116 
 Chevreul, 129 
 
 Church, 8. R., 138 
 Clark, 114 
 
 Conté, 19, 21 
 
 Craig, E. H. C., 92 
 
 Damiens, A., 35 
 Davey, W. P., 159 
 Davis, L. L., 124 
 Ditmar, 62 
 Donath, E , 129 
 Dow, D. B., 29 
 Downs, C. R., 78 
 Doyle, H. L., 18 
 Drew, H. D. K., 17 
 Dunstan, A. E., 83, 106, 107, 112, 155 
 Dupré, F., 149 
 Dupré, M., 148 
 
 Ellis, C., 37 
 
 Emtage, R. H., 100 , 
 Engler, 85 
 
 Errera, J., 140 
 
 Evans, A. C., 44 
 Evans, R. D., 64 
 
 Fieldner, A. C., 38 © 
 Fisher, H. C., 154 
 Fleming, 163 
 
 Gardner, H. A., 18, 25, 38, 49, 153, 158 
 
 Geitel, 130 
 
 Gesner, 109 
 
 Géodrich, P., 140 
 Graefe, E., 90, 111, 126 
 Green, 48 
 
 Greider, 61 
 
 Griin, 80 
 
 Gunning, 89 
 
 Hammond, 116 
 Hamor, 104 
 Hepworth, T. C., 55 
 Hershmann, 44 
 Hird, 116 
 
 Holde, D., 110 
 Holdt, P., 158 
 Horne, W. D., 23 
 Horton, P. M., 23 
 Howard, R. D., 78 
 Hubbard, P., 138 
 Hulme, W., 48 
 Hutin, 111 
 
 Icard, 8., 148 
 Instit. of Petroleum Technologists, 83 
 Irvine, R., 35, 57 
 
 Johnson, 163 
 Jones, 114 
 
 Kawai, 8., 92 
 Kewley, J., 106 
 Kjeldahl, 89 
 Klein, C. A., 48 
 Kobayashi, 8., 92 
 Kramer, G., 37 
 
 Laird, W. G., 37 
 
 Langton, H. M., 25, 38, 67, 70, 71, 99, 
 109, 124, 130-133, 135, 137 
 
 Lawrence, J. C., 123 
 
 Lebeau, P., 35 
 
 Lewes, V. B., 114, 115 
 
 Lewis, M. H., 148 
 
 Lewis, R. H., 138 
 
 Lewkowitsch, J., 85, 130, 131 ~ 
 
 Lomax, E. L., 112 
 
 Lucas, A., 55 
 
 Mabery, C. F., 99 
 
 Maderna, 140 
 
 Mansbridge, W., 87 
 
 Marcusson, J., 89, 96, 109, 111, 121, 126, 
 130 
 
 Martin, G., 24 
 
 May, P., 54 
 
 Mayer, 18 
 
 McCourt, C. O., 37 
 
 McGuire, J. A., 37 
 
 Mitchell, C. A., 19, 21, 55 
 
 Morgan, G. T., 126 
 
 Morrell, J. C., 38 
 
 Morrell, R. 8., 149, 157, 159, 162, 163 
 
 Neal, R. O., 14, 29, 31 
 
 175 
 
176 
 
 Nichols, 48 
 Niepce, J. N., 140 
 Nuttall, 47 
 
 Pailler, E. C., 111 
 Parrish, J., 48 
 
 Pearson, A. R., 114 
 Peckham, 8. F., 92 
 Perrott, G. St. J., 40, 44 
 Pickering, G. F., 90, 135 
 Pritchard, T. W., 24 
 
 Ralston, O. C., 82 
 
 Ramsay, W., 92 
 
 Redwood, Sir B., 85, 87, 106 
 
 Reeve, C. 8., 138 
 
 Remfry, F. G. P., 155 
 
 Richardson, C., 67, 68, 89, 92, 93, 98, 
 111, 165 
 
 Richardson, G. B., 171, 172 
 
 Rubencamp, 18 
 
 Sarnow, C., 87 
 Saybolt, 85 
 
 Scharff, C. E., 126 
 Scheele, 19 
 Schippel, 63 
 Schreiber, O., 144 
 Schweizer, V., 125 
 Sell, G., 105 
 
 Selvig, W. A., 17, 38 
 Serle, 67 
 
 Sievers, E. G., 28 
 Singleton, F., 154 
 Sinkinson, E., 114 
 Slater, W. E., 31 
 Smith, J. Cruickshank, 13, 49, 51 
 Smith, J. E., 44 
 Smith, Watson, 104 
 
 INDEX OF 
 
 ACENAPHTHENES, 78 
 Acetylene black, 35, 37 
 Acetylenes, 76 
 Acid-proof cements, 145, 146 
 floors, 145, 146 
 Acid-washed black, 23 
 Ageing of bituminous materials, 139-140 
 Agglomerated particles of blacks, 59 
 Air-drying black enamels, 160-161 
 Albertite, 103 
 Alcohols, 79 
 Aniline black, 157 
 Animal charcoal, 23 
 Anisotropic fillers in rubber, 64 
 Anisotropy, 64 
 Anthracenes, 78 
 Archangel pitch, 123 
 Asphalt, 66, 67, 69 
 Bermudez, 93 
 composition of, 75-82 
 dampcoursing, 146-147 
 definition of, 68, 70, 168 
 
 Index of Names 
 
 Soane, C. E., 80 
 
 Spielmann, P. E., 67, 83, 139, 140 
 Stanton, F. M., 38 
 
 Stewart, E. G., 115 
 
 Stockings, W. E., 114 
 
 Stopes, M. C., 113 
 
 Strasser, R., 129 
 
 Sullivan, J. V., 56 
 
 Svedberg, 48 
 
 Szarvasy, E., 37 
 
 Taylor, G. B., 17 
 Thiessen, R., 40, 59 
 Thole, F. B., 112, 115 
 Tindale, H., 121, 166 
 Toch, M., 138 
 
 Uhlinger, R. H., 37 
 Underwood, N., 56 
 
 Vitruvius, 55 
 Vogt, W. W., 64 
 
 Ward, G. J., 146 
 Warnes, A. R., 114, 116 
 Weber, H. C. P., 163 
 Weill, 8., 110 
 
 Weiss, J. M., 78, 114, 138 
 Wheeler, R. V., 113, 114 
 Wiegand, 62, 63 
 Wiegner, 48 
 
 Wieland, W., 125 
 
 Wijs, 90 
 
 Wilkins, O., 23 
 
 Wilton, 116 
 
 Wright, 115, 166 
 Wurtz, 129 
 
 Zerr, 18 
 
 SUBJECTS 
 
 Asphalt, early history of, 66, 67 
 in roadway construction, 164 
 Judea, 140 
 light sensitiveness of, 140 
 Marcusson’s subdivision, 96 
 native, occurrence of, 91-96 
 origin of, 92-93 
 paints, 151-155 - 
 resins, 140 
 roof felting, 143, 144 
 Trinidad Lake, 92-95 
 uses, 83 
 waterproofing, 146-147 
 
 Asphaltenes, 96, 121, 166 
 in asphalt, 96 
 in roadtars, 166 
 
 Asphaltic cements, 166 
 pyrobitumens, 69, 72, 103 
 
 definition of, 71 
 
 Asphaltites, 69, 72, 98-102 
 definition of, 71 
 
 Asphaltogenic acids, 96 
 
Index of Subjects 177 
 
 Asphalt pavement, 164-165 
 surface of, 165 
 surface phenomena in, 165-166 
 Asphalts, blown residual, 109, 110 
 petroleum residual, 105, 108, 109 
 sludge, 111 
 sulphurised, 110, 111 
 Asphaltum, 66 
 Patagonian, 162 
 Syrian, 162 
 
 - Barytes, 62, 63 
 Bitumen, 66, 67, 69 
 composition of, 70, 75 
 classes of, 72 
 Dead Sea, 66 
 definition of, 67, 70, 168 
 Egyptian, 66 
 occurrence in nature, 91 
 Bituminous fabrics, 142 
 cements, 145-146 
 paints, 151 
 paving materials, 164-168 
 varnishes, 160-161 
 Bituminous materials, 67 
 ageing of, 139-140 
 B.S. specification, 167, 168 
 carbonisation of, 139 
 chemical tests, 84, 88—90 
 complete classification, 72, 73 
 composition, 75-82 
 effects of moisture on, 139 
 for fabrics, 142 
 for floorings, 144-145 
 heat tests, 86, 87 
 light sensitiveness of, 140 
 physical tests, 84-86 
 preliminary classification, 68 
 solubility tests, 87, 88 
 types of, 69 
 weathering of, 138-140 
 Blacklead, 16 
 Black pigments, 13, 14 
 classification of, 14 
 fineness of, 48 
 formation of, 14 
 “long ” and “‘short,”’ 56, 60 
 paint-making, 47 
 properties of, 13 
 properties of, in ink-making, 56, 57 
 specific gravity, 47 
 tinting strength, 49, 50 
 uses of, 13 
 uses of, in ink-making, 55-60 
 Black stoving enamel, 157 
 Blast-furnace tar, 72, 116, 119 
 pitch, 72, 116, 119 
 Boiled oil, 55 
 Bone black, 22, 23 
 Bone tar, 137 
 pitch, 137, 153 
 Brown coals, 126 
 Brunswick blacks, 151, 157 
 
 Cannel coals, 104, 126 
 Carbon, 13 
 ‘short ” and “ long,” 59 
 
 Carbon, as rubber pigment, 61, 62 
 Carbon black, description of, 27 
 analyses of, 38, 39, 45 
 apparent surface of, 62 
 bibliography, 40, 41 
 B.S.S. in paint, 52, 53 
 Channel process, 31, 32 
 extent of industry, 28 
 from coke-oven gas, 35 
 in ink manufacture, 57-59, 60 
 in paint manufacture, 47, 51 e 
 methods of analysis, 38, 39 
 methods of formation, 31 
 plants in use and yields, 28 
 Plate process, 33 
 production in 1923, 171, 172 
 properties of, 37 
 rotating cylinder process, 34, 35 
 rotating disc process, 33 
 selling price of, 27 
 theory of formation, 29, 30 
 uses of, 40 
 variation in yield of, 38 
 various methods of manufacture, 35, 
 
 37 
 Carbon inks, 55 
 Charcoal blacks, 14, 22 
 Charcoals, analyses of, 25 
 production, 14, 23, 24 
 Chrysene, 57, 78 
 Coal, 71 
 action of solvents on, 114 
 botanical origin of, 113 
 brown, 126 
 defined, 113 
 occurrence of, 113 
 various classes, 114 
 Coal tar, 112 
 characteristics of, 112 
 classification of, 115 
 composition, 114-115 
 distillation of, 116-119 
 production of, 112 
 Coal-tar pitch, 112, 119, 167-169 
 B.S. specification, 168-169 
 characteristics of, 114, 119 
 composition of, 114, 115 
 for roofing purposes, 143 
 for waterproofing, 147 
 properties of, 121 
 quantities of, 112 
 Coke-oven gas, 35 
 Coke-oven-tar, 115, 116 
 Coke-oven-tar pitch, 115, 119 
 Compound carbonaceous blacks, 15 
 Compounding ingredients in rubber, 
 61 
 
 Cotton black grease, 129, 134 
 Cotton-oil refining, 133, 134 
 Cotton pitch, 129 
 Cotton-seed fatty acids, 134 
 mucilage, 134 
 pitch, 129, 133-134 
 Cotton pitch, 129, 133-134 
 Cotton soap-stock, 134 
 Cotton stearine pitch, 133-134 
 Cracking, 14, 112, 136 
 
178 Index of Subjects 
 
 Cyclo olefines, 77 
 Cyclo paraffins, 76 
 
 Damp-coursing, 146, 147 
 Damp-proofing, 146, 147 
 Deposited carbon blacks, 14 
 Diolefines, 76 
 
 Diphenyls, 77 
 
 Dippel’s oil, 137 
 
 Dispersed particles of blacks, 59 
 Drop black, 23 
 
 Elastic constants, 64 
 Elaterite, 103 
 Emulsification, 131 
 Emulsions, bituminous, 165 
 
 Fatty acid pitches, 129 
 composition of, 136 
 properties of, 137 
 
 Fatty acids, 79, 129 
 acetic series, 79 
 distillation, 129-132 
 oleic series, 80 
 
 Fatty oils, constitution of, 129 
 saponification, 129-131 
 
 Fillers for paint, 152 
 rubber, 61-64 
 
 Fixed blacks, definition of, 13 
 preparation of, 22-25 
 
 Gilsonite, 98, 99, 100 
 in enamels, 157 
 in Japans, 156 
 Glance pitch, 98, 100 
 Grahamite, 98, 101, 102 
 Graphite, analyses, 20 
 analysis of, 17 
 as a lubricant, 18 
 in pencil manufacture, 19, 21 
 manufacture, 17 
 occurrence of, 16 
 paint, 18 | 
 pencil markings, 19, 21 
 production of, 16 
 properties, 16, 17 
 uses of, 17, 18 
 
 Hydrocarbons, 75 
 acetylene, 76 
 benzene, 77 
 cyclic, 77, 78 
 naphthenic, 76, 105 
 olefine, 75 
 paraffin, 75, 105 
 
 Impregnating compounds, 149 
 
 Impsonite, 103 
 
 Indenes, 77, 78 
 
 Indian ink, 55 
 
 Insulating papers, 148 
 
 Insulating varnishes, 162, 163 
 chemical problems of, 163 
 formula of, 163. 
 
 Isotropic fillers in rubber, 64 
 
 Ivory black, 23 
 
 Japans, 155-159 
 
 bituminous materials for, 156 
 
 formule, 157 
 
 pitting of, 158 
 
 with water thinners, 159 
 Jellying of asphalt paints, 154-155 
 Judean asphalt, 140 
 
 Ketones, 79 
 Lampblack, 13, 42 
 
 analyses, 45 
 collection of, 43, 44 
 
 contrasted with carbon black, 44, 45 
 in ink-manufacture, 56, 57, 59, 60 
 
 production, 42-44 
 properties, 42 
 quality of, 42 
 yield, 42 
 Lignite, 71 
 tar, 126 
 pitch, 126, 127, 153 
 
 Magnetite, 15 
 Manganese black, 15 
 Manjak, 100 
 
 Metallic blacks, 14, 15 
 Mexphalte, 162, 173 
 Mineral black, 25 
 Monocyclic benzenes, 77 
 
 Naphtha, coal-tar, 152 
 petroleum, 107, 152 
 wood, 152 
 
 Naphthalenes, 77 
 
 Naphthenes, 76 
 
 Native asphalts, 72, 91, 168 
 
 Natural gas, 27, 28, 31, 37 
 composition, 30 
 
 ' testing, 29 
 
 Nigrosines, 15 
 
 Nitrogenous compounds, 81 
 
 Non-asphaltic pyrobitumens, 69 
 definition of, 71 
 
 Oils for ink-making, 55 
 
 Oil-gas pitch, 72, 127, 128 
 tar, 72, 127, 128 
 
 Olefine acetylenes, 76 
 
 Olefines, 75 
 
 Ozokerite, 70, 149 
 
 Paint solvents, 152 
 
 Paints, bituminous, 151 
 graphite, 18 
 
 Particle size, 48, 62 
 
 Peat, 71, 125 
 distillation products, 125, 126 
 tar, 125 
 
 Petrolenes, 26, 121, 166 
 
 Petroleum, 70, 71 
 comparison of derivatives, 98 
 distillation schemes, 106, 107 
 metamorphoses, 93 
 origin of, 92, 136 
 principal refinery products, 107 
 products as solvents, 152 
 
Index of Subjects 179 
 
 Petroleum, residual pitch, 105, 108, 109 Saponification, 129-131 
 
 residuals, 108 Shales, 25, 71, 127 
 world’s production, 106 Solvents, comparative volatilities, 
 Phenols, 79 paint and varnish, 152 
 Pigments, artists’, 54 Soot, 42 
 Pigments, black, 47 Stearine pitches, 129 
 bulking value, 49 composition, 136, 137 
 colour of, 50 palm oil, 133 
 fineness of, 48, 49 properties of, 129, 137 
 in rubber mixtures, 61-64 uses in cables, 149 
 oil absorption of, 49 floorings, 145 
 _ pencil, 19, 21 paints, 151-155 
 tinting strength of, 49, 50 varnishes, 137 
 Pitch, 66, 67, 69, 167-169 whale oil, 133 
 Archangel or pine, 123 yield of, 132 
 blast-furnace tar, 72, 116, 119 Stress-strain relationships, 62, 63, 64 
 bone-tar, 72, 137 Sugar-house black, 22 
 B.S. specification, 168-169 Sulphur compounds, 80, 81 
 coal-tar, 72, 112, 119 
 coke-oven tar, 72, 115, 119 Tar, 67, 69, 166 
 cotton, 72, 129, 133, 134 classification, 72, 73 
 definition of, 71, 168 definition of, 71, 167 — 
 fatty acid, 72, 129, 136, 137 distillation, 116-120 
 oil-gas tar, 72, 127, 128 solvents, 152, 153 
 peat tar, 72, 125 Tar macadam, 165 
 _producer-gas tar, 116, 119 oil, 169, 170 
 residual, 68 Thermal decomposition, 14 
 rosin, 72, 124,125 Thinners, 151-153 
 shale-tar, 72 Torbanites, 104 
 stearine, 72, 129 Trinidad Lake asphalt, 92-95, 164, 165 
 water-gas tar, 72, 127, 128 colloidal properties, 165 
 wood-tar, 124, 153 Turpentine, 24, 152 
 wool, 129 
 Plumbago, 16 Varnish, 138, 151 
 Poisson’s ratio, 64 air-drying, 162 
 Polycyclic polymethylenes, 76 for inks, 55, 58-60 
 Polymethylenes, 76 insulating, 162, 163 
 Printing ink, 55 ~* lithographic, 58, 59 
 main classes of work for, 55 Vegetable black, 44 
 methods for practical test, 58, 59 charcoal, 24 
 testing methods, 58 Vine black, 24 
 tests on carbon black for, 57, 58 
 Protection of metal surfaces, 153 Wax, montan, 70 
 Pyrenes, 57, 78 _ native mineral, 71 
 Pyrobitumens, 69, 91 paraffin, 70 
 definition of, 70 Waterproofing, various, 146-148 
 Pyrolusite, 15 Wood, charcoal, 22, 23 
 Pyrolysis, 112, 136 yield of, 24 
 Pyropissite, 104 classes of, 123 
 Wood distillation, 24, 123 
 Residual pitches, 68, 113, 167 solvents, 152 
 Residuals in pyrogenous distillation, tar, 124 
 113 pitch, 124, 153 
 Resin acids, 80 oe Wool grease, ihe 
 Resins, 152 este Feat tee 1 roe. 129. , 
 Rosin, 149 Pei ae 4 Wurtzilite, 108, sey 8 $e Re 
 oil, 149 ee Sue e oes “o> 
 Rubber pigments, 61 se bgpecnaaa Weel grease, 135 
 practical tests, 63 one caeat » 2929 
 
 results for mixings, 63 > Sing oxide i peel tuber, 3%, 83 
 
 TEP ree y 
 
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