11 BR.ARY OF THE. UNIVERSITY Of ILLINOIS 666 I<6 no. 16-23 CENTRAL CIRCULATION AND BOOKSTACKS The person borrowing this material is re- sponsible for its renewal or return before the Latest Date stamped below. You may be charged a minimum fee of $75.00 for each non-returned or lost item. Theft, mutilation, or defacement of library materiali can be cauui for student disciplinary action. All material* owned by the University of Illinois Library are the property of the State of Illinois and are protected by Article 16B of ffl/nois Criminal Law and Procedure. TO RENEW, CALL (217) 333-8400. University of Illinois Library at Urbana-Champaign MAY 2 9 2001 When renewing by phone, write new due date below previous due date. L162 UNIVKRSILYOl ILLINOIS BULLETIN ISSUED WEEKLY Vol. XI. JULY 13, L914. v. 46 [Entered as second-class matter December LI, 1912, at the i»>st office at Urbana, Illinois, under the \< :1 ol Vugusl J4. 1912.] BULLETIN No. 22 DEPARTMENT OF CERAMICS R. I' Sill. I.. Acting Director THE INFLUENCE OF CHLORIDES OF CAL- CIUM AND IRON WHEN PRECIPITATED IN A PORCELAIN BODY SOME COBALT-URANIUM COLORS BY B. S. RADCLIFFE mm.isHKD by the university of Illinois, urban \ 1 9 1 3 - I ') I 4 Authorized Rt>prinl from I'olumi XVI, 1914, Transactions American <• THE INFLUENCES OF CALCIUM AND IKON CHLOR- IDES PRECIPITATED IN A PORCELAIN BODY BY B. S. i: \Ih i n ' i The production of vitrified red Horn tile has given manu- facturers considerable trouble. Pra rieally, the only solution of the problem has been to secure a good red burning clay, and burn to a degree of vitvfic tion such thai the red color is no1 de stroyed. In mos1 instan< >. ii lias been found impossible t ake red bodies thai have I -s Hum four or five percenl absorption, and in many cases !he absorption is considerablj greater than this. Good red bodii - can be made by mixing the proper ; >unts of feldspar and Mini with "Helmstadter" clay, and burning to practically complete vitrification. This clay is very line grained, plastic, and is red in color, The original red color of the clay is only slightly altered during burning, up to tin- point when the porosity is reduced to aboul three percent. A higher temperature causes the red color to deepen and gradually cihange to dark brown and finally black. The deepening of the color begins aboul cone '>. and by cone 8 tin- body is dark brown to black. The burning qualities of this clay seem to be duo to the fad Unit the iron is present in a highly disseminated state. This investigation was made \<> determine whether uniform colors of iron in varying shades could lie produced by precipi- tating the chlorides of iron and calcium in a body. A cone 10 porcelain was chosen for the body. It is not considered an ideal one for the production of red tile, and one containing more ball clay in place of the china clay would prob- ably he better, since it would have less porosit.\ in bhe >\ry state and would require less fluxing action \'<>v complete vitrification on that account. Procedure. The three corner bodies as gfoowi the i ri axial diagram were mixed by wel grinding for five hours in a poreelaindined hall-mill. The tri-axial group of 66 bodies was made by blending bhese I hree bodies. CALCIUM AND 1RO.V CHLORIDES IN PORCELAIN BODY E^CQ^ CALCIUM AND [RON CHLORIDES IN PORCELAIN BODJ .<, The mixtures were pu1 in frail jars and shaken thoroughly so as to obtain uniform mixtures. The chlorides were precipi- tated by adding XII, oil and ■Ml, B 00 3 and shaking. The slips were allowed to stand for a day, after which Bhey were poured into plaster molds. When the excess water had been ab- sorbed the bodies were removed from the molds, and dried in an oven to 200 0. After crushing in a porcelain mortar, triangular floor-tile were made by the dry-press process, aboul 1<» percent of water being used. Thej were burned to cones 5, 7. 9 and 11 in an open, down-draft, gas-fired tesl kiln. Results. Those bodies bigh in iron were most plastic, and those high in lime were Least plastic. This was shown both by the working properties of the bodies in the plastic state and l>\ the strength of the dried tile. Vitrification— None of the bodies were completely vitrified at cone 5, although those high in iron and lime were hard and dense, thu.se liig-h iu lime being the hardest. At cone 7. all bodies containing over four percenl of iiuxes were vitrified. All bodies were completely vitrified at cone 9, those containing over 7 per- cent of fluxes being overburned. Bodies containing -\ percent and over of fluxes were over- burned at cone 11. The remainder retained their shape but had a glassy surface with the exception of 1, 2 and 3. Color— Bodies free from iron burned white and were prac- tically uniform in color at vitrification. Tlio.se containing 1 percent of iron were cream colored when burned under oxidizing conditions, but a good uniform graj color was obtained w men the tile were reduced ai the end of the burn. The lime had very Little effect upon the color of bodies containing 1 percent of iron. Bodies containing l! percent of iron were pink or Light red at cone 5, above which temperature they changed to brownish buff with the exception of No. 4. which became dark yellowish gray. Bodies containing 4 bo 1<> percent of iron burned red to dark Vi'il at cone .">. Those containing f. 5 and 6 percent were still wA at cone 7. The color was much deeper than at cine ."> and in- 4 CALCIUM A.ND IRON CHLORIDES IN PORCELAIN BODY ereased with increased iron. Two percent of lime did not affect the color of bodies containing 5 percent or over of iron. The remainder of the series did net produce desirable colors for floor tile. CONCLUSIONS Uniform gray colors of pleasing shades can he made by pre- cipitating to 2 percent of iron in a porcelain body and burning properly. Uniform red colors can be produced by precipitating 4 to G percent of iron in a porcelain body which, if burned properly, would not have more than 3 to 4 percent porosity. ( leramic Laboratory, r/niversitj of Illinois DISCUSSION Mi-. Parmelee: I should like to ask the reason for using calcium salt. Mr. Uadclijfe: Calcium chloride was added, because it is ;i soluble salt : and it was thought, that the intimate mixture of the calcium and iron obtained in this way, might throw some light on the cause of the varied color effect, produced by iron in different clays. SOME COBALT-URANIUM COLORS B1 B. S. BADCLIPFB There are four coloring oxides, namely, copper, chromium, nickel and iron, which under proper conditions produce green colors in bodies and glazes. In physical mixtures, \\e are able to produce greens by blending blue and yellow. The object of this investigation was bo determine whether green could be produced by blending cobalt-blue and uranium- yellow. Series A was made up as follows: TABLE I— SERIES A A. v. A 3 \ t A D \a L'.O: 6H.0 \li( )H) 1 .0 50.0 40.0 25.0 0.9 50.0 40.0 25.0 0.8 50.0 4O.0 25.0 0.7 50.0 40.0 25.0 0.6 50. 10. Zn( ) 25.0 The stains were thoroughly mixed, calcined to cone 5, ground to pass a 200 mesh screen and added to a mat glaze having the formula, 0.1 K,o j 0.2 OaO I 0.36 Al,<> :; 1.36 Si<>. 0.7 PbO J The glaze was then burned to cone 05. The result was a yellow- ish green glaze with blue specks. This was due bo the fact thai the cobalt was not thoroughly disseminated. A blue stain CoA i<» Calc. A1 2 8 4o ZnO 45 was then made, calcined to cone 7. and ground to pass a 200 mesh screen. Three frits wen- made using the mat glare as before. SOME COBALT-rRANH'M COLORS TABLE II— SERIES B Feldspar CaCO» Red lead Eng. china clay Tenn. ball clay. Flint Blue stain Na 2 U 2 0, 6 H 2 . 17.6 l ; . 6 17.6 6.3 6.3 6.3 50.5 50 . ."> 50 . 5 11.0 11.0 11.0 10.0 10.0 10.0 4.6 4.6 4.6 10.0 10.0 10.0 25.0 35.0 45.0 When applied as glazes, B 1 gave an olive green, B 2 and B 3 rich chocolate browns. These results indicate thai the ratio of uranium to cobalt is too high. The nexl step tried was to use the nitrates of coball and uranium, l)\' fritting in Hit- mat glaze. TABLE III — SERIES C c i c., ':: Feldspar i ; . 6 6.3 50.5 1 1 .0 10.0 1.6 3.5 10.0 17.6 6.3 50.5 1 1 .0 10.0 1 .6 3.5 L2.0 L7 . 6 CaCO; c>.:; Red lead 50.5 11.0 Tenn. ball clay Flint 10.0 4.6 3.5 1 'milium nitrate 1 5 . The frits were ground, and a .scries of glazes made by blend- ing with the original mat glaze. Bright glazes vcie made by adding 20 parts of flint to the frits of this series. The mat glazes were olive green, (', having a bluish shade. Of the bright glazes C 3 was deep green in color, and Cj and C, were green with a bluish shade. SOME COBALT-1 RANI1 M COLORS Conclusions: Green glazes and mats can be made by blend ing cobalt and uranium in the righil proportions, which is be tween four and five parts of uranium nitrate to one pari of co bait nitrate. ( leramic Laboratory • I niversitj >■! Illinois. DISCUSSION Prof. Orion: I do not know, whether there has ever been any repor1 made, about the peculiar green developed by one of the roofing-tile plants in this country l>y the use of coball oxide and sulphate of antimony. These coarsely ground chemicals were added to a roughly prepared glaze; and the resiiH was thai they succeeded in getting a very passable green. At least it liooked like a good green om the roof, hut if looked a1 close by, the size of the blue and yellow spots was so large as to be offen- sive. The reason, thai they did this, was thai they were working in ;i sulphurous close atmosphere, that spoiled other greens, and they thought, that if they had a sulphate bo start with, it would not do any harm. Mr. Radcliffe: I might say that a man in the berra-cotta business in Kansas bold me that he used cobalt and uranium to produce greens. lie did not led me, however, until we worked :t out. lie was using il for polychrome work. The cobalt-uran- ium green that ho produced was better than any other green that he could make for this purpose. It did no! run or blend oil' with the white, but instead he could get a firm line between the green and the white, or whatever base was beneath the green poly- chrome work. MHBBBMtf^HU UNIVERSITY OF ILLINOIS-URBANA 3 0112 052567093 'X m\ 5