Technical Paper 282
DEPARTMENT OF THE INTERIOR
ALBERT B. FALL, SECRETARY
BUREAU OF MINES
H. FOSTER BAIN, DIRECTOR
B 454494
ANALYSIS OF DETONATING AND
PRIMING MIXTURES
BY
C. A. TAYLOR and W. H. RINKENBACH
B.9. Soul

こ
​
ENT
PART
OF
THE
INT

June 1932
WASHINGTON
GOVERNMENT PRINTING OFFICE
1922
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2
First edition, January, 1922.
CHEMICAL
LIBRARY
TP
273
T24-
miscal Lib.
fron
-19-30
CONTENTS.
Page.
5
5
6
7
7
7
9
Introduction
Acknowledgments.
General methods_
Nitrogen determination
Nitrometer method_
Örndorff method_
Analysis of detonating compositions__
Physical tests of initiating materials_
Chemical analysis of initiating materials.
Materials of detonating compositions_
Structure of detonators__.
Method of removing charges from detonators_.
9
11
Sampling
Determining moisture in detonating mixtures_
Methods of analyzing detonating mixtures.
2RHW
12
13
14
14
Simple analysis of a detonating mixture containing fulminate
and chlorate__
14
Analysis of a mixture of fulminate and chlorate for free
mercury
16
Detailed analysis of a detonating composition containing ful-
minate and chlorate.
16.
Impurities
17
Methods of analysis_
17
Analysis of a detonating mixture containing fulminate, chlorate,
and tetryl_.
19
Analysis of detonating compositions containing fulminate,
chlorate, and TNT.
20
21
21
21
2 227 22 2222*
Analysis of detonating compositions containing fulminate,
chlorate, nitromannite, and nitrocellulose_--
Analysis of priming charges in detonators__
Analysis of an initiator fulminate and nitrocellulose__.
Analysis of an initiator containing loose fulminate and
chlorate___.
Analysis of an initiator containing chlorate and picric acid_
Analysis of a priming composition for detonators containing
lead nitrate and tetry or lead nitride and TNT_
Analysis of percussion priming compositions--.
Differentiation between primers and detonators.
Nature of priming compositions_.
Primer composition materials_
Sampling-
23
25
Identification of primer materials.
25
Determination of moisture_
26
Analysis of single primers__
26
Analyses of typical priming mixtures.
27
Analysis of a priming composition containing fulminate, anti-
mony sulphide, chlorate, and glass---
27
Analysis of a priming composition containing chlorate, anti-
mony sulphide, lead sulphocyanide, and TNT_.
28
Analysis of a priming composition containing red phosphorus,
lead picrate, and barium nitrate___.
29
Analysis of a priming composition containing potassium chlorate,
antimony sulphide, lead nitrate, and TNT_
29
Analysis of a priming composition containing potassium chlorate,
antimony sulphide, lead nitrate, TNT, and glass.
Analysis of a priming composition containing fulminate, lead
picrate, antimony sulphide, barium nitrate, and barium chlo-
rate___
30
30.
3
4
CONTENTS.
Analysis of percussion priming compositions-Continued.
Analyses of typical priming mixtures-Continued.
Analysis of a priming composition containing silver permanga-
nate, antimony sulphide, TNT, and red phosphorus__.
Analysis of a complex noncorrosive priming composition__
Analysis of a priming composition containing fulminate, anti-
mony sulphate, barium nitrate, picric acid, and glass____
Publications on investigations of explosives_
Page.
31
31
31
33
ILLUSTRATIONS.
PLATE I. Detonator holder.
FIGURE 1. Orndorff nitrogen apparatus_.
2. Three types of detonators_
Page.
12
8
12
THE ANALYSIS OF DETONATING AND PRIMING
MIXTURES.
By C. A. TAYLOR and W. H. RINKENBACH.
INTRODUCTION.
Many schemes of analysis are published that take up the examina-
tion of metals or other substances in a special and comprehensive
way and serve as a general basis of procedure to be modified by the
analyst to suit his particular need. These basic methods and modi-
fications have been brought to a high state of perfection in various
industries, as in the analysis of iron, steel, and coal. Therefore it is
comparatively easy for a chemist in one of those industries to find a
method that covers his special problem.
In the examination and manufacture of explosives conditions are
radically different. New materials and combinations are being tried
as explosives, and the variety of both is so great that it is imprac-
ticable to give a definite method of analysis applicable to even one
class of explosives, such as detonating and priming compositions or
dynamites. Consequently, a real need exists for the adaptation of
the methods followed in the analysis of stable materials to the sensi-
tive compounds and mixtures used in explosives in order that the
analyst will know how to proceed with maximum safety and con-
fidence.
This paper is intended to satisfy part of this need and is a con-
tinuation of the publications on explosives analysis from the Pitts-
burgh laboratory of the Bureau of Mines.¹ The methods given herein
are those used in practical work and are not intended to fill the re-
quirements of a research chemist working on a particular compound.
However, they do cover the needs of a chemist analyzing explosive
compositions and desirous of results that are accurate within the
limits of the variation of the mixtures themselves.
The explosives chemical laboratory at Pittsburgh is now preparing
a bulletin on explosives, their materials, and analysis.
ACKNOWLEDGMENTS.
The authors express their appreciation of the helpful suggestions
and criticisms of this paper by A. C. Fieldner, supervising chemist,
and Dr. C. E. Munroe, chairman of the committee of explosives
investigation of the National Research Council.
¹ Snelling, W. O., and Storm, C. G., The analysis of black powder and dynamite, Bull.
51, Bureau of Mines, 1916, 80 pp.; Storm, C. G., The analysis of permissible explosives,
Bull. 96, Bureau of Mines, 1916, 88 pp.
5
6
ANALYSIS OF DETONATING AND PRIMING MIXTURES.
GENERAL METHODS.
In analyzing explosives the general practice is to make as many
separations as possible by the use of solvents. The subsequent evapo-
ration of the solvent leaves the extracted ingredient chemically un-
changed, when it can be weighed and its percentage calculated. The
solvent should be driven from explosive compounds by a current of
dry air or by spontaneous evaporation at room temperature, precau-
tions being taken to prevent moisture from being deposited on the
residue of the explosive by the cooling effect of the evaporating
solvent.
The most powerful explosives are comparatively insensitive in
solution. Nitroglycerin may be burned in ethereal solution, but this
procedure is inadvisable with large quantities, as the ether evaporates
very readily.
Adding strong acid or alkali to an explosive is inadvisable unless
it is in solution, as the heat evolved in the reactions that sometimes
take place may cause the explosion of the entire sample.
All explosives should be kept neutral, as slight acidity causes many
compounds to become much more sensitive to shock or heat.
When an unknown explosive compound or mixture is being dried,
the temperature should be kept below 75° C., as some substances tend
to decompose and become very sensitive at higher temperatures and
others are volatile enough to cause considerable loss.
In all analyses there are two steps-the identification of the various
ingredients and their separation, or their separation and subsequent
identification. The microscope should be used freely in identifying
materials and detecting their impurities. With inorganic materials,
the usual qualitative tests are used and quantitative separations are
then made. The organic compounds, except those in general use
which are easily identified through practice, are often difficult to
identify. Their physical appearance is carefully noted, the details
being studied with the microscope, and their identity is determined
by comparison with known materials. If the organic compounds can
be separated and purified, they may be easily identified by the system
given by Mulliken.²
Organic compounds are usually separated from inorganic sub-
stances by solvents. When two organic nitro compounds with very
similar characteristics are present, such as tetryl and TNT, it may
be necessary to take them out in solution together and identify them
by color tests. By determining the nitrogen content of the mixture
and calculating from the known nitrogen content of the individual
substances, it is possible to get results very close to the amounts
actually used in manufacture.
2 Mulliken, S. P., A method for the identification of pure organic compounds. New
York, 1904, vol. 1, pp. 9–14.
GENERAL METHODS.
7
NITROGEN DETERMINATION.
For determining the nitrogen in an organic compound or mixture
the Dumas method may be accepted as standard, but must be used
with the precautions given in Technical Paper 160.3
NITROMETER METHOD.
4
The du Pont nitrometer is used to determine all organic and
inorganic nitrates. It should be remembered that the presence of cer-
tain mononitro and dinitro compounds affects the accuracy of this
method.
ORNDORFF METHOD.
During the recent war another method was developed by W. R.
Orndorff and R. R. Braden, of Cornell University. With proper
precautions, this method gives good results. The procedure follows:
Weigh out 0.2 to 0.3 gram of the sample; place it in a 300-c. c.
Kjeldahl flask and add 0.1 to 0.2 gram of red phosphorus and 20 c. c.
of hydriodic acid (specific gravity, 1.7). When the substance to be
analyzed―tetryl, for example—is high in nitrogen, about 1 gram of
iodine should be added to the hydriodic acid to insure reduction.
The flask is now heated on a water bath for 1½ hours, and the mix-
ture agitated several times while on the bath. After removal from
the bath it is carefully heated over a free flame to gentle boiling, then
cooled slightly. Next there are added 1 gram of copper sulphate, 45
grams of potassium sulphate, and 55 c. c. of concentrated sulphuric
acid; then the flask and its contents are heated until all the iodine
has been driven off. Complete oxidation is indicated if the contents
of the flask have a clear greenish-blue color.
The whole is cooled and the ammonia is distilled into a standard
N/5 sulphuric acid solution after the acid contents of the flask have
been neutralized. When the distillation is complete, the excess of
sulphuric acid is titrated with a N/10 sodium hydroxide solution,
using methyl red or cochineal as the indicator.
Care should be taken in digesting and distilling the iodine to avoid
local overheating. The iodine driven off may be caught and saved
by placing a balloon flask over the mouth of the Kjeldahl flask so
that it does not touch the neck of the Kjeldahl. If recovery of the
iodine is not desired, a current of warm air decreases the time needed
for driving it off.
The ammonia is distilled with steam, the sodium hydroxide with
which the solution is neutralized and then made alkaline being added
3 Cope, W. C., and Taylor, G. B., The determination of nitrogen in substances used in
explosives: Tech. Paper 160, Bureau of Mines, 1917, pp. 5-10.
* Pitman, J. R., Analysis of nitric and mixed acids by Du Pont's modification of the
Lunge nitrometer: Jour. Soc. Chem. Ind., vol. 19, 1900, p. 983; Lunge, G., Du Pont's
nitrometer: Jour. Soc. Chem. Ind., vol. 20, 1901, pp. 100–102.
8
ANALYSIS OF DETONATING AND PRIMING MIXTURES.
cautiously with the steam. Just after the mixture has been made
alkaline the ammonia comes over so rapidly that the standard sul-
phuric acid should be agitated to prevent local saturation and con-
sequent loss of ammonia, or a special tube should be used, as shown
in the accompanying sketch (fig. 1). A blank should be run with
each set of determinations.

FIGURE 1.-Orndorff nitrogen apparatus.
Occasionally it is necessary to make the ultimate analysis of a
compound in order to identify it, but usually such a compound can
be identified by appearance, melting point, nitrogen content, crystal
form, or other criteria. Two similar organic substances are seldom
used together.
The following sources of information have been freely consulted
in the writing of this paper: "High Explosives," by E. de W. S.
Colver, 1918, New York; "Initialexplosivstoffe " by Richard Escales
and A. Stettbacher, Leipzig, 1917; and "Explosives," by Arthur
Marshall, London, 1915.
CHEMICAL ANALYSIS OF INITIATING MATERIALS.
9
ANALYSIS OF DETONATING COMPOSITIONS.
PHYSICAL TESTS OF INITIATING MATERIALS.
Simple physical methods of testing the efficiency of these initiating
materials have been developed. These are:
1. The Trauzl lead-block test.5
2. The plate test.
3. The nail test."
4. The sand test.8
5. Dupré test."
9
6
CHEMICAL ANALYSIS OF INITIATING MATERIALS.
Frequently it is desirable to know the chemical composition of
initiating mixtures. The purpose of this paper is to give the ana-
lytical procedure to be followed.
Because of the nature of the materials to be handled it is necessary
to take special precautions against accidents in the examination of
detonators. The following methods and procedure have been used
or tested in the explosives chemical laboratory of the United States
Bureau of Mines and have proved satisfactory within the limits
shown. This paper does not attempt to give exact methods covering
all possible materials and mixtures that have been tried at various
times, but the general methods and their specific application to some
usual and unusual mixtures will suggest other modifications that
will be applicable to a new mixture.
MATERIALS OF DETONATING COMPOSITIONS.
The substances and compositions proposed or patented for use as
detonating agents include a wide variety of chemical compounds.
The lists below are incomplete, but they comprise the most common
and many of the more unusual materials found in detonators. In-
organic materials include the following:
LIST OF INORGANIC MATERIALS.
Mercury fulminate (Hg(ONC)2).
Silver fulminate (Ag(ONC)).
Lead azide (PbN®).
Sodium azide (NaN,).
Mercury azide (HgN:).
Silver azide (AgN3).
Silver acetylide (Ag₂C2).
Nitrogen sulphide (N4S4).
Lead thiocyanate (Pb (SCN)2).
·
Mercury thiocyanate (Hg(SCN)2).
5 Hall, Clarence, and Howell, S. P., Investigations of detonators and electric deto-
Bull. 59, Bureau of Mines, 1913, p. 61.
nators
6
• Ibid., pp. 24-25.
7 Snelling, W. O., The energy of explosives: Proc. Eng. Soc. Western Pennsylvania, vol.
28, Nov., 1912, p. 673.
8 Storm, C. G., and Cope, W. C., The sand test for determining the strength of detona-
tors: Tech. Paper 125, Bureau of Mines, 1916, 66 pp.
• Dupré, F. H., and Dupré, F. V., 44th Annual Report of His Majesty's Inspectors of
Explosives, 1919: London, 1920.
62955°—22——————2
10
ANALYSIS OF DETONATING AND PRIMING MIXTURES.
LIST OF INORGANIC MATERIALS continued.
thiocyanate
Copper - ammonium
(Cu (NH3SCN)2).
Lead thiosulphate (PbS₂Os).
Copper - ammonium thiosulphate
(CuS2O3.4NH³.H₂O).
Red phosphorus (P).
Sulphur (S).
Aluminum powder (Al).
Manganese dioxide (MnO2).
Potassium chlorate (KCIO;).
Ammonium chlorate (NH₁ClO3).
Barium chlorate (Ba (ClO3)2).
Potassium bromate (KBrO3).
Ammonium perchlorate (NHClO₁).
Potassium nitrate (KNO:).
Ammonium nitrate (NH.NO₂).
Barium nitrate (Ba(NO3) 2).
Mercury chromate (HgCrO₁).
Lead oxide (PbO2).
Barium oxide (BaO2).
Barium silicide (BaSi₂).
The organic compounds comprise:
CH3
Calcium silicide (CaSi₂).
Potassium silicide (K.Si).
Sodium carbonate (Na2CO3).
Potassium bicarbonate (KHCO3).
LIST OF ORGANIC MATERIALS.
C-NO₂
Tetranitromethane
C(NO2)4
NH₂
Trinitrotoluene
H=CC=C-H
NO₂
Tetranitraniline
Q₂N C-CCNO₂
HC C-CNO₂
CH3
Trinitroxylene
Q₂N-C˜C˜C-NO₂
HC_C_C-CH₂
Trinitrophenylmethylnitramine
(tetryl)
NO2
NO 2
NINO 2
N-CH₂
O₂N-C-CCNO₂
HỒ CÁCH
HC
NO₂
OH
Sugar of milk (lactose)
C-NO₂
Picric acid
HC_C=C₂H
NO₂
OK
Mannitolhexanitrate
(nitromannite)
NO₂
Potassium picrate
HC CECH
NO₂
Trinitroresorcin
он
NO₂
на сосон
NO₂
Hexanitrodiphenyl
O₂N
C12H22O11 H₂O
H₂C-ONO₂
H C-ONO₂
H C-ONO₂
HC-ONO₂
H C-ONO₂
2
H₂C-ONO₂

HỒ CÁCH
HỒ CÁCH
NO₂
HC.
NO₂
сн
STRUCTURE OF DETONATORS.
11
LIST OF ORGANIC MATERIALS-COntinued.
Hexanitrodiphenyloxide
O₂NC CC NO₂ NOC C CH
Hồng CH
NO2
Diphenylamine
N
I-Z
H
NO 2
HỒ
CÁCH
HC-CCH
насон
H
H
HC-C=CNO₂
Hexanitrosulphobenzide
0-5-0
Benzoylperoxide.

گیا
CNO₂ NO₂C
C=CNO₂
нассн
HC
CH
HC CÁCH
HCC=CH
насосн
NO₂
H
H
HỒ CÁCH
NO₂
Hexamethylenetriperoxiddiamine
CHÈO-O-CH,
N-CH, 0 0 CHUN
2
CH₂ O O CH2
2
Some of the foregoing materials have been patented, but have
never been sold on a commercial scale and probably will not be be-
cause of the high cost of production, a tendency to decomposition, or
some other unfavorable factor. The methods of analysis given cover
all of the initiating detonating compositions in more or less general
use and as many of the others as it is possible to include at present.
STRUCTURE OF DETONATORS.
A detonator, often called a blasting cap in commerce and industry,
consists of a copper capsule or shell and the inclosed charge. The
capsule, closed at one end, is 1 to 2 inches long and has a diameter
of approximately three-sixteenths inch. The open end of the cap
is made to fit over the end of a safety fuse, on which it is securely
crimped. The charge is either entirely compressed or, if loose, is
held in place by a reinforcing cap to keep it from falling out on
handling and to insure its maximum effect when ignited by the spit
from the burning powder core of the fuse.
An electric detonator is of slightly greater diameter than a deto-
nator and has a loose priming charge above the main compressed
charge. The two terminals of the electric wires project into the cap
through a sulphur plug and are connected by a fine platinum or iron
wire termed the "bridge wire." This sulphur plug is pressed into
12
ANALYSIS OF DETONATING AND PRIMING MIXTURES.
the copper shell so that the bridge wire is embedded in the priming
charge, and it is held in place by a plug of asphalt composition, which
also renders the detonator waterproof. Molten sulphur is poured
over the asphalt until the cup is entirely filled. The ignition of the
charge results from the heating of the bridge wire due to its resist-
ance when an electric current is passed through it. Sketches of the
three types of detonators described above are given as figure 2.
METHOD OF REMOVING CHARGES FROM DETONATORS.
To remove the charge from a detonator that has no reinforcing cap
it is only necessary to squeeze the sides of the cap gently to loosen
the charge, which can then be dumped out.
1
2
a.
3
ая
FIGURE 2.—Three types of
detonators: 1, detonator
of simple type; 2, rein-
forced detonator; 3,
electric detonator.
detonating main charge;
b, priming charge; o,
sulphur plug; d, as-
phalt composition;
fused sulphur.
e,
A pair of 6-inch gas pliers may be used; a
guard of heavy belting about 8 inches square
is kept over the pliers at the rivet. As the
cap is squeezed, it should be held at arm
length and in such a position that if it should
explode the guard will shield the operator.
Only gentle pressure should be used and the
cap should be deformed as little as possible.
After each application of pressure any
loosened portion of the charge should be
dumped out.
A better method is to roll the detonator
carefully between two pieces of smooth hard-
wood board, dumping out the loosened charge
after each rolling.
To remove the charge from a detonator
having a reinforcing cap, it is necessary to
cut into the open end of the cap with a pair of angle-cutting pliers.
The cap is then turned while the pliers hold the piece cut so that a
strip of copper in the form of a spiral is torn off. When the rein-
forcing cap is reached this is loosened and removed, after which the
charge in the cap is loosened and removed as directed above.
It has been recommended that the following procedure be fol-
lowed in opening electric detonators: A hole, just large enough to
hold the detonator and deep enough so that the top of the charge
is just below the surface of the steel, is drilled in a heavy steel block.
The cap is then cut off even with the steel surface by a quick blow
with a sharp wood chisel. This method is relatively safe so far as
danger to the manipulator is concerned, but it is seldom used because
frequent explosions will spoil the chisel.
An improvement over this method consists of cutting into the
sulphur filling and asphalt, and then peeling the copper down in a
BUREAU OF MINES
TECHNICAL PAPER 282 PLATE I

DETONATOR HOLDER.
UNIV
OF
MICH
STRUCTURE OF DETONATORS.
13
spiral until the plugs are loosened enough to be withdrawn easily.
During this process the detonator should be held in the hand or in
a pair of gas pliers. Extreme care should be taken not to cut into the
portion of the shell containing the charge.
The explosives chemical laboratory, with the assistance of the
instrument makers of the bureau, has built an apparatus for holding
the detonator and cutting through the cap at any desired point by
a sharp knife or rotating disk. The mechanism is so arranged that
should a charge explode the operator would be fully protected. As
yet, however, no explosions have occurred when this apparatus has
been used. Plate I is a photograph of the detonator holder.
As soon as the detonator is opened, the loose priming charge is
emptied out, weighed, and analyzed separately. The main charge is
loosened by squeezing or rolling and removed as described above.
SAMPLING.
Usually the charge from each detonator is analyzed separately.
When the charge consists of a priming and a main charge, or a
booster" and a main charge, care is taken to remove, weigh, and
analyze each part separately.
66
As the condition of a single detonator affects the whole blast, infor-
mation is usually sought in the analysis as to the variations in a lot
of detonators rather than the average composition of a lot. However,
when the average composition is sought, it is best to open several
detonators and to mix the similar parts, thus making a blend or
composite of corresponding parts of the charge. The analysis is
then run in duplicate or triplicate. The weight of each portion of
each charge is recorded in order that an average may be taken.
In one series, the weight of the charge in the different grades of
detonators using the fulminate and chlorate mixture ran as follows,
when taken from the detonators:
Weight of charge in detonator.
No.
1__
2
3.
4
Weight of charge,
grams.
No.
0.30 5__
40 6
.52 7.
65 8___
Weight of charge,
grams.
0.75
1.00
1.50
2.00
When a loose wad of nitrocellulose is used as a priming charge in
an electric detonator, this wad averages from 0.02 to 0.025 gram in
weight, irrespective of the size of the detonator. When a loose ful-
minate or fulminate-chlorate mixture is used for the priming charge,
its average weight is usually a trifle over 0.3 gram. These quantities
suffice to cover the bridge wire and insure ignition.
Typical analyses of detonating compositions containing the more
usual ingredients used commercially are given on the following pages.
14
ANALYSIS OF DETONATING AND PRIMING MIXTURES.
DETERMINING MOISTURE IN DETONATING MIXTURES.
Moisture is seldom determined in detonating mixtures, for the
latter are usually dry and must remain so if the proper results are to
be obtained. The moisture content is usually but a few hundredths
of 1 per cent.
If for any reason it is advisable that moisture be determined, the
procedure is as follows: The contents of one or two detonators are
spread out on a tared 3-inch watch glass and weighed, then kept
for three days in a sulphuric acid desiccator which holds a small
beaker containing mercury. The beaker of mercury is placed in the
desiccator in order that a constant mercury-vapor pressure may be
maintained, as if this is not done any metallic mercury contained in
fulminate is apt to volatilize, causing the figure for moisture to be
entirely too high. At the end of three days the watch glass and
sample are again weighed and the loss is taken as moisture.
METHODS OF ANALYZING DETONATING MIXTURES.
SIMPLE ANALYSIS OF A DETONATING MIXTURE CONTAINING FULMINATE
AND CHLORATE.
Fulminate may be tested for qualitatively 10 by bringing the sub-
stance to be tested into contact with a solution made up of 20 to 25
parts of a 5 per cent solution of potassium bromate and 4 to 5 parts
of concentrated hydrochloric acid. The development of blue color
indicates the presence of a fulminate.
The following method is used when it is desired to get a fairly
accurate idea of the fulminate and potassium-chlorate contents of a
simple detonating mixture of these two compounds without taking
into consideration any impurities they may contain.
A sample of approximately 1 gram is weighed out, transferred to a
small beaker, and digested in the cold with distilled water. It is
then caught on a dried and weighed filter or in a Gooch or alundum
crucible and given several washes with distilled water, the filtrate
ar the washes being retained. For a 1-gram sample it is not neces-
sary to use more than 100 c. c. of water for all purposes.
The residue of mercury fulminate left on the filter or crucible is
dried for three hours at 50° C., care being taken not to exceed this
temperature. After cooling, the residue is weighed, and the increase
is taken as mercury fulminate.
As some of the mercury fulminate is present in the filtrate, it is
necessary to determine the amount. Half or all of the filtrate-wash
10 Langhans, A., Reaktion des Knallquecksilbers mit Halogenaten und Hypohalogenaten :
Jour, prakt. Chem., Bd. 98, 1918, pp. 255-314.
STRUCTURE OF DETONATORS.
15
solution is taken, rendered strongly ammoniacal, and the mercury
in it precipitated as with hydrogen sulphide, continuing the pass-
ing through of the hydrogen sulphide until the cold solution is
saturated with the gas. The mixture is then brought just to the
boiling point, allowed to cool to air temperature, and caught on a
filter or Gooch crucible previously dried at 110° C. The precipitate
is washed several times with distilled water containing a small
amount of ammonium sulphide, dried at 110° C., and weighed.
The weight of the precipitate is multiplied by the factor 1.22327,
which gives the corresponding weight of mercury fulminate. This
calculated weight should be added to that found previously and the
´whole calculated to a percentage basis.
A check on the foregoing is obtained by determining the chlorate
content in half the filtrate-wash solution.11 This is done by adding
5 c. c. of a 30 or 40 per cent solution of formaldehyde, a measured 50
c. c. of N/10 silver nitrate, and a few drops of nitric acid to the
solution contained in a flask or beaker. The mixture is heated for
half an hour on the steam bath with occasional shaking. Silver
chloride is precipitated according to the reaction:
KC103+3 HCHO+AgNO,-3 HCOOH+AgCl+KNO3
The amount of chlorate reduced may be determined either by
filtering off, washing, drying, and weighing the precipitated silver
chloride or by titrating the excess silver nitrate with N/10 NHCNS,
according to Volhard, using a ferric alum indicator. The presence
of the excess of formaldehyde has no effect on the titration of the
excess silver nitrate.
The weight of silver nitrate reduced is calculated to potassium
chlorate (1 c. c. of N/10 AgNO,-.012256 gram KCIO,), and this is
calculated to a percentage basis on the whole sample.
A simple detonator composition often contains a small amount of
a binding material. If both fulminate and chlorate are determined
directly, the difference between 100 per cent and their sum will give
a fairly accurate idea of the amount of binder present.
In European detonators ammonium chlorate is sometimes mixed
with the potassium chlorate. If ammonia is found qualitatively, it
is determined quantitatively by distilling a water extract of the
detonator charge with sodium hydroxide in the usual way, catching
the distilled ammonia in standardized sulphuric acid and titrating
the excess sulphuric with standardized sodium hydroxide, using a
cochineal indicator.
11 Storm, C. G., The analysis of permissible explosives: Bull. 96, Bureau of Mines, 1916,
pp. 63-64.
16
ANALYSIS OF DETONATING AND PRIMING MIXTURES.
་
ANALYSIS OF A MIXTURE OF FULMINATE AND CHLORATE FOR FREE
MERCURY.
Mercury fulminate frequently contains free mercury to a greater
or less degree, and occasionally it is desirable to determine how much
is present in a fulminate-chlorate detonating mixture that is under
investigation.
For a simple fulminate-chlorate mixture this is done as follows:
A sample of from 1 to 5 grams of the detonating mixture is weighed
out, transferred to a previously dried and weighed filter or crucible,
and washed with distilled water to remove the chlorate. It is then
washed with more than enough concentrated ammonia to dissolve
all the fulminate present, then washed with dilute ammonia and
distilled water.
The residue should consist of metallic mercury and any binding
material and phlegmatizer present. If inspection shows metallic
mercury alone, this is directly determined by drying the filter or
crucible and its contents in a sulphuric acid desiccator containing a
small beaker half full of mercury, and weighing. If matter other
than metallic mercury is found in the residue, the mercury is dis-
solved on the filter or crucible with dilute nitric acid (20 per cent).
The filtrate and water-washes therefrom are combined and the mer-
cury determined by precipitation in ammoniacal solution with hy-
drogen sulphide, filtering, washing, drying at 110° C., and weighing.
The weight of mercuric sulphide multiplied by 0.862165 gives the
corresponding weight of metallic mercury, which is calculated to per
cent of the sample taken.
The above method for a simple mixture can be extended to more
complex mixtures if desired.
A solution of sodium thiosulphate may be used instead of ammonia
to dissolve the mercury fulminate, and the volumetric method devised
according to a process first used by Brownsdon, and based by him on
the fact that sodium hydroxide is produced in the reaction, may
be employed here.
DETAILED ANALYSIS OF A DETONATING COMPOSITION CONTAINING FUL-
MINATE AND CHLORATE.
Occasionally it may be desirable to make a thorough analysis of a
fulminate-chlorate detonating composition in order to get all avail-
able data. Such analyses are rarely made, and definite and exact
knowledge of the nature and origin of all the impurities which may
be present, particularly after some decomposition has occurred, is
lacking.
STRUCTURE OF DETONATORS.
17
IMPURITIES.
The fulminate may contain the impurities mentioned below:
1. Metallic mercury. Although all of the mercury may be dissolved
in the nitric acid when the reaction incident to the mixing of the
alcohol and nitric acid-nitrate solution has proceeded for some time,
some metallic mercury may be thrown out and contaminate the
finished product.
2. Oxalic acid. The presence of oxalic acid is due to oxidation of
the alcohol in the manufacturing process and to incomplete subse-
quent purification.
3. Free nitric acid. The presence of free nitric acid in commercial
fulminate is due to incomplete washing of the crude product during
manufacture.
4. Chlorine and hydrochloric acid. Gray fulminate is frequently
purified (in reality bleached) with hydrochloric acid, which usually
results in not all of this acid being removed.
5. Mercurous chloride. The presence of mercurous chloride is also
due to the use of hydrochloric acid for bleaching gray fulminate.
6. Copper chloride. Gray fulminate is sometimes bleached with
cuprous chloride, which explains the presence of the latter.
7. Basic mercuric salts. Practically nothing is known as to the
causes or nature of basic mercuric salts.
The chlorate may contain the following impurities:
1..Chloride. The presence of chloride is due to the method of
manufacture and to incomplete purification of the crude product.
2. Potassium bromate. All potassium chloride from the Stassfurt
deposits contains bromide, which is converted into bromate when
the chloride is converted to chlorate by electrolytic methods.
METHODS OF ANALYSIS.
1. Metallic mercury. A sample of the detonator charge weighing
between 1 and 5 grams is transferred to a dried and weighed filter
or crucible where it is washed with water, and then with concentrated
ammonia. The filter or crucible is then dried in a calcium-chloride
desiccator containing a little mercury in a beaker and weighed, the
weight being taken as metallic mercury; if inspection shows the
presence of other insoluble matter, the mercury without drying, is
dissolved on the filter with dilute nitric acid, and then precipitated
from ammoniacal solution with hydrogen sulphide.
2. Oxalic acid. The ammoniacal solution that results from combin-
ing the filtrate and the washes in the foregoing process is treated with
a dilute solution of c. p. calcium chloride, a little ammonium nitrate
solution being added first. The mixture is allowed to stand for 12
62955°—22—3
18
ANALYSIS OF DETONATING AND PRIMING MIXTURES.
hours after it is brought to boiling. The calcium oxalate precipitated
is then filtered off and can be determined either by weighing as such
or by titration in a 5 per cent sulphuric acid solution at 85 to 95° C.
with approximately N/20 potassium permanganate solution.
3. Nitric acid. A preliminary qualitative test of the detonator
charge may be made with blue litmus paper, which will not be turned
red by thoroughly washed fulminate, or the diphenylamine test may
be used. For quantitative work, the total acidity of the sample is
determined by agitating the sample (preferably about 5 grams in
weight) with 100 c. c. of water and titrating with N/10 sodium
hydroxide, using phenolphthalein as indicator. The result is calcu-
lated to per cent of nitric acid. From this figure are to be subtracted
any values found for oxalic and hydrochloric acids.
4. Chlorides and hydrochloric acid. A sample of the detonator
charge weighing between 5 and 10 grams, if possible, is leached with
distilled water. The filtrate and several washes are combined and
the chloride and hydrochloric acid present determined either by pre-
cipitation of silver chloride with subsequent drying and weighing,
or by titration with a N/10 silver nitrate solution. The result should
be calculated to either chloride or hydrochloric acid as indicated by
other impurity determinations.
5. Mercurous chloride. The presence of mercurous chloride is deter-
mined by washing a sample of the charge thoroughly with cold con-
centrated hydrochloric acid ¹² and testing the residue with ammonia.
For a quantitative determination, a 5-gram sample of the charge is
washed on a previously dried and weighed crucible with concen-
trated hydrochloric acid. Mercurous chloride and metallic mercury
are left behind. If examination has shown nothing else in the
residue, the crucible can be dried in a sulphuric acid desiccator con-
taining a beaker of mercury and weighed. Subtraction of the weight
of metallic mercury previously found will give the weight of mer-
curous chloride. If, however, other substances are in the residue, the
chloride and metallic mercury are dissolved out in aqua regia, the
residue washed several times with water, and the total mercury in
the filtrate and washings determined by precipitation with hydrogen
sulphide. The weight of mercuric sulphide equivalent to the weight
of metallic mercury is calculated and subtracted from that found.
The remaining mercuric sulphide is calculated to mercurous chloride.
6. Copper. Copper found as an impurity in fulminate may be
present as fulminate or chloride. The manner of combination is not
definitely known, but the metal is assumed to be present as cuprous
chloride. It should be determined in a solution containing all of
the fulminate, as follows: Precipitate the mercury and copper from
12 Escales, Richard, and Stettbacher, A., Initialexplosivstoffe: Leipzig, 1917, p. 142.
STRUCTURE OF DETONATORS.
19
an ammoniacal solution with hydrogen sulphide and wash with very
.dilute ammonium sulphide; then wash with warm dilute nitric acid
which dissolves any copper sulphide present. The filtrate is tested
for copper with ammonia (blue coloration) and any copper found
present is reprecipitated from ammoniacal solution with hydrogen
sulphide. This is washed on the filter with very dilute ammonium
sulphide, dried at 100° C. and weighed as CuS, or ignited to CuO
and weighed as such. It is then calculated to cuprous chloride.
CuSX1.03544=CuCl.
CuOX1.24456=CuCl.
7. Potassium bromate.13 A 2-gram sample is dissolved in 100 c. c.
of water and any undissolved fulminate filtered off and washed.
Five c. c. of a 10 per cent solution of potassium iodide and an equal
quantity of normal hydrochloric acid are added to the combined
filtrate and washes. Not more than a trace of blue color should
appear within 10 minutes. A blank test is made, using 100 c. c. of
water for comparison. The method is made quantitative by the
titration of the liberated iodine with N/10 Na₂S₂O, after the treated
solution has stood in the dark for one hour.
3
ANALYSIS OF A DETONATING MIXTURE CONTAINING FULMINATE,
CHLORATE, AND TETRYL.
Among the newer types of detonators are those containing a
chlorate-fulminate mixture over a compressed charge of tetryl (tri-
nitrophenylmethylnitramine).
The charges are ordinarily so placed that they can be separated
mechanically. Under these circumstances the fulminate-chlorate
mixture is analyzed as directed before, the purity of the tetryl be-
ing established by a determination of its melting point, which should
be between 127.5° and 129° C., but never below 127.5° C. Determina-
tion of acidity may also be desirable, and is done by boiling a 10-
gram sample with 50 c. c. of distilled water, filtering, washing with
distilled water, and titrating the filtrate and washes with N/10 so-
dium hydroxide, using several drops of phenolphthalein as an indi-
cator. Acid-free tetryl has an acid reaction and is slightly soluble
in water, so 0.2 c. c. of N/10 sodium hydroxide must be allowed for
this. The result is calculated to per cent of sulphuric acid. The
nitrogen content, which is 24.4 per cent for pure tetryl, may also be
determined and the purity calculated from this.
Sometimes an accurate and complete separation of the two charges
is impossible. In that event the combined charges of two or three
detonators are weighed out and transferred to a filter or crucible
13 Zeitschrift für das gesamte Schiess-und Sprengstoffwesen: Jahrg. 8, 1913, p. 102.
20
ANALYSIS OF DETONATING AND PRIMING MIXTURES.
+
previously dried at 100° C. and weighed. The chlorate and some of
the fulminate are extracted with distilled water, the filtrate being
saved. In this solution chlorate and fulminate are determined as
directed before (see p. 14).
If a determination of free mercury is not required the crucible and
its contents are dried for five hours at 70° C., cooled, and weighed.
The fulminate is then dissolved out on the filter with approximately
30 per cent warm hydrochloric acid, followed by about five wash-
ings with distilled water. Then the crucible and its contents are
dried for three hours at 110° C., cooled, and weighed. The loss in
weight represents fulminate and should be added to the fulminate
found in the water extract. The residue in the filter or crucible
may be regarded as tetryl and calculated to the percentage basis as
such, but if information is desired regarding any additional insoluble
impurities that may be present, the residue may be dissolved out with
acetone, benzene, or orthonitrotoluene, and the crucible again dried
and weighed to determine the loss in weight, which is regarded as
tetryl.
ANALYSIS OF A DETONATING COMPOSITION CONTAINING FULMINATE,
CHLORATE, AND TNT.
Fulminate-chlorate-TNT detonating compositions are analyzed
in exactly the same way as fulminate-chlorate-tetryl compositions.
The melting point of TNT is 80.6° C., but its "setting point" is
usually determined instead, 79.6° C. being regarded as the minimum
for satisfactory TNT. In determining acidity, it is not necessary to
subtract from the sodium hydroxide reading to compensate for the
acidity of the substance, as is necessary with tetryl. Pure TNT con-
tains 18.5 per cent nitrogen, therefore a determination of the nitro-
gen content will serve as a criterion of the purity of the sample under
inspection. The TNT in solution in acetone or benzene may be re-
covered, identified, and tested to determine its melting point and
nitrogen content.
If it is desired to determine the amount of free mercury present,
the drying and weighing after the water extraction are followed
by the extraction of (1) the TNT and (2) the fulminate in turn
with (1) acetone, benzol, or orthonitrotoluene and (2) concentrated
ammonia. The filter or crucible is dried and weighed after each
extraction, the loss in weight being taken as TNT and fulminate
respectively. After the ammonia extraction the drying should be
done in a desiccator containing calcium chloride and a little metallic
mercury. The metallic mercury remaining is then determined either
by direct weighing or by solution in dilute nitric acid and precipi-
tation in ammonical solution with hydrogen sulphide, as directed
before.
STRUCTURE OF DETONATORS.
21
ANALYSIS OF DETONATING COMPOSITIONS CONTAINING FULMINATE, CHLO-
RATE, NITROMANNITE, AND NITROCELLULOSE.
Fulminate-chlorate-nitromannite-nitrocellulose detonating compo-
sitions are analyzed in four stages as follows:
1. The chlorate and some of the fulminate are extracted with
water in the usual way, the chlorate and mercury in the solution
being determined by reduction with formaldehyde and precipitation
with hydrogen sulphide. The crucible or filter containing the resi-
due is dried for five hours at 50° C.
2. The remaining fulminate is extracted with concentrated ammo-
nia, then washed with dilute ammonia and distilled water. If pre-
ferred, hydrochloric acid (1:3) may be used. The crucible and its
contents are again dried at 50° C. for five hours. The loss in weight
is taken as fulminate, but this can be checked by aliquoting the solu-
tion and precipitating the mercury with hydrogen sulphide in the
usual way.
3. The nitromannite (hexanitromannitol) is removed by extrac-
tion with alcohol, benzene, or absolute ether. After drying for five
hours at 70° C., the loss in weight is taken as nitromannite. The
result can be checked by throwing the nitromannite out of the alco-
holic solution with water, filtering, drying at 50° C., and weighing.
4. The residue may be regarded as nitrocellulose, but if the result
is to be checked and the presence of other substances investigated,
the residue may be extracted with acetone and the crucible dried and
weighed. The loss is nitrocellulose.
ANALYSIS OF PRIMING CHARGES IN DETONATORS.
An initial priming charge is placed in some detonators to set off
the actual detonating charge. This priming charge is always taken
out of the detonator separately, weighed, and given a separate an-
alysis. If it consists solely of nitrocellulose it need only be weighed
and identified. The course of analysis of several typical priming
charges is given below:
ANALYSIS OF AN INITIATOR CONTAINING FULMINATE AND NITROCELLULOSE.
Samples taken from one or more detonators are weighed and trans-
ferred to a filter or crucible that has been previously dried at 100° C.,
cooled, and weighed. The fulminate is thoroughly extracted with 30
per cent hydrochloric acid, the residue of nitrocellulose is washed sev-
eral times with distilled water, and the crucible and contents are
dried for five hours at 70° C., cooled, and weighed. The loss in
weight is taken as fulminate and the weight of the residue is re-
garded as nitrocellulose, both weights being calculated to a per-
centage basis.
L
22
ANALYSIS OF DETONATING AND PRIMING MIXTURES.
ANALYSIS OF AN INITIATOR CONTAINING LOOSE FULMINATE AND CHLORATE,
The analysis of an initiator containing loose fulminate and chlorate
is carried out in the same manner as that described for a fulminate-
chlorate detonating composition.
ANALYSIS OF AN INITIATOR CONTAINING CHLORATE AND PICRIC ACID.
A weighed sample is transferred to a dried, tared filter or crucible.
The picric acid is extracted with ether or benzene. The filter and
residue of potassium chlorate are dried at 100° C. for five hours,
cooled, and weighed. The loss in weight represents picric acid; the
residue represents chlorate. This latter may be checked by dissolv-
ing with water, reducing with formaldehyde in the presence of nitric
acid and an excess of silver nitrate, and back-titrating with N/10
ammonium thiocyanate.
An alternative method is to extract the chlorate and some of the
picric acid with distilled water and to determine the chlorate in the
solution by reduction with formaldehyde as directed above.
ANALYSIS OF A PRIMING COMPOSITION FOR DETONATORS, CONTAINING LEAD NITRATE
AND TETRYL OR LEAD NITRIDE AND TNT.
The lead nitride is used as a priming charge over the organic nitro
compounds, and with sufficient care these can be separated as the
charge is removed, then weighed and identified.
If it is impossible to keep the nitride and the nitro compound
separated, they are thoroughly mixed and an analysis of the mixture
is made as follows:
Weigh a sample of from 1 to 5 grams and transfer it to a filter
or alundum crucible that has been previously dried at 100° C. and
weighed. The tetryl or the TNT as the case may be, is extracted
with absolute ether, orthonitrotoluene, or some other solvent. The
crucible with its content of residual lead nitride is carefully dried
at 50° C., cooled, and weighed.
ANALYSIS OF PERCUSSION PRIMING COMPOSITIONS.
DIFFERENTIATION BETWEEN PRIMERS AND DETONATORS.
When a detonator is used, it is desired that the detonation wave
shall cause a detonation in the main blasting charge; any flame which
may be produced is of secondary consideration. Primers, on the
other hand, are used to supply a flame at a definite time and place
for the purpose of ignition only; detonation is not desired.
NATURE OF PRIMING COMPOSITIONS.
Two classes of primers are in use:
(1) Those containing mercury fulminate, and (2) those which do
not, such as the sulphocyanate mixtures.
ANALYSIS OF PERCUSSION PRIMING COMPOSITIONS.
23
Antimony sulphide or ground glass is used in practically all primers
to increase the sensitivity to friction. They all contain an oxidizing
and a reducing agent, one or both of which might be classed as sen-
sitizing materials. By themselves they may be very stable and insen-
sitive, but in the proper mixtures they tend to form gaseous products
very easily.
Sulphur is one of the most common substances of this type. Alone
it is very insensitive and burns slowly in the air, but when mixed
intimately with a strong oxidizing agent, such as potassium nitrate
or potassium chlorate, the reaction between them becomes very rapid
when once started. A black powder mixture of sulphur, charcoal, and
nitrate is very effective as a second-order explosive. It is too insensi-
tive to act as a satisfactory priming mixture, but if potassium chlo-
rate is substituted for potassium nitrate and the charcoal is eliminated
the basis of a primer is obtained. Usually, however, more active
reducing agents than sulphur are used.
Potassium chlorate is the best-known oxidizing agent for primers.
Its only disadvantage is that in combustion potassium chloride is
formed, tending to cause after-corrosion in the barrels if used in guns;
hence, if so used, proper precautions should be taken to prevent this
corrosion.14
PRIMER COMPOSITION MATERIALS.
Mercury fulminate (Hg(ONC)2).
Lead azide (PbNe).
Sodium azide (NaN3).
Potassium nitrate (KNO3).
Barium nitrate (Ba(NO3)2).
Lead nitrate (Pb(NO3)2).
Antimony sulphide (Sb₂S2).
Phosphorus sulphide (PS).
Nitrogen sulphide (N4S4).
Red phosphorus (P).
Sulphur (S).
Carbon (C).
Powdered glass.
Potassium carbonate (K₂CO:).
Sodium carbonate (Na2CO3).
Barium carbonate (BaCO3).
Lead ammonium thiosulphate
(PbS2O3.2 (NH4)2S2O3).
INORGANIC.
Potassium chlorate (KClO3).
Calcium chlorate (Ca (CIO3)2).
Potassium perchlorate (KCIO₁).
Mercury chromate (HgCrO₁).
Lead chromate (PbCrO4).
Lead oxide (PbO2).
Barium oxide (BaO2).
Antimony oxide (Sb2O3),
Potassium permanganate (KMnO4).
Silver permanganate (AgMnO₁).
Silver acetylide (Ag₂C2).
Potassium silicide (K.Si).
Barium silicide (BaSi2).
Calcium silicide (CaSi₂).
Lead thiocyanate (Pb (SCN)2).
Copper thiocyanates.
Copper ammonium thiosulphate
CuS2O3.2 (NH4)2S2O3.
14 Huff, Wilbert T., The cause and prevention of after-corrosion in the bores of fire-
arms: Jour. Ind. Eng. Chem., vol. 39, 1920, p. 862.
24
ANALYSIS OF DETONATING AND PRIMING MIXTURES.
ORGANIC.
Hexanitrosulphobenzide
0-0
CH3
O₂N
NO 2
Trinitrotoluene
NO2
NO2 NO2
NO;
NO 2
NO;
NO₂
Hexanitrodiphenyl

он
NO 2
NO2 NO2
O₂N
NO2
Picric acid
NO,
NO2
NO2
NO 2
Lead trinitroresorcinate
OK
NO 2
NO2
Potassium picrate
O₂N
NO2
Pb.
Benzoyl peroxide
Diphenylamine
NO 2
O
0
Diazoaminobenzene
NO 2
N-N-H
NN=N

HZ
H
N
NH-NO.

NO2
NO,
Trinitronitranilide
Hexamethylenetriperoxiddiamine
CH₂-0-0-CH₂
N
-CH2-0-0-CH2-N
·CH2—0—0—CH₂
Nitropentaerythritol
NO2
CH₂-O-NO,
CH2-O-NO,
CH2-0-NO₂
CH₂-O-NO,
Primers are much more sensitive than detonators, for they are
made to ignite by percussion. Accordingly, when primer caps are
being opened, it is necessary to handle them more carefully than de-
tonators, but as the charge is very much smaller, there is but little
danger of severe injury.
The individual charge is so small that it is only with the more
simple mixtures that it is possible to make an analysis on a single
charge with any accuracy. Accordingly, the charges are withdrawn
from as many caps as is convenient and the weight of each is recorded
ANALYSIS OF PERCUSSION PRIMING COMPOSITIONS.
25
so as to ascertain the average charge weight as well as the variation
in charges. A composite sample of all opened is made, therefore the
result reported is the average of a number.
SAMPLING.
When taking out the charge from the primer, the anvil is first re-
moved and the cap tapped to loosen and jar out the charge. When
this work is being done it is well to wear heavy gloves to prevent
injury to the hands. The following procedure is recommended as
being the safest.
The ordinary pliers used for holding primers are modified so
that the opening on one side of the jaws is covered. The primer
is held with the anvil toward the open side and about flush with
the side of the jaws; then, while the cap is held with the pliers in
such a way that it can be seen only in a mirror set at an angle of about
45 degrees on the desk, the anvil is pried or pulled out by a sharp
hook. After the anvil has been removed the charge is usually
jarred out, but if the charge resists this method, it may be loosened
by a maple or orangewood stick with a sharp point. If the charge
does ignite during any part of the foregoing, the only damage is the
loss of the charge, as the gloves will protect the hands.
IDENTIFICATION OF PRIMER MATERIALS.
Probably the most difficult part of the analysis of primer charges
is the identification of the compounds used. The sample is usually
so small that not many tests can be made upon it. One of the.first
steps taken, and often the only one necessary to give a fair idea of
the substance used, is the making of a careful examination of the
sample under the microscope. For this work a binocular microscope
is best, but the usual type with a comparatively low magnification is
also very satisfactory. Occasionally it is necessary to pick out a
few crystals of some compound on which to make special qualita-
tive tests, and to crystallize out small quantities on a slide in order
to note crystal form and growth. Some of the compounds may be
identified by the ordinary qualitative tests for bases, acids, and other
compounds or elements. A thorough qualitative examination is
always worth while, however, and is often essential before it is pos-
sible to obtain accurate quantitative results.
Primers are so varied in composition that it is impossible to work
out a general scheme of analysis which may be followed. Identifica-
tions may, however, follow a partial quantitative separation. In the
following pages several methods that are adapted to different mix-
tures will be outlined. They do not cover all the possible combina-
tions, nor all the substances that may be combined in primers, but
do cover most of the materials in common use.
26
ANALYSIS OF DETONATING AND PRIMING MIXTURES.
DETERMINATION OF MOISTURE.
Moisture is not usually determined. In order that the composition
may be effective it must be kept dry, and it is therefore usually pro-
tected by a coating of shellac or collodion. The charge is so small,
and so much time is required to remove it, that a moisture determina- .
tion could not be accurate. When the analysis is for the purpose
of determining the cause of misfires the condition of the charge
should be carefully noted under a microscope before the charge is
removed. If it seems that the moisture content may be high the
moisture may be determined by weighing several primers on a watch
glass and exposing them for three days in a sulphuric acid desiccator.
As a check, in order to be sure that the loss was not surface moisture,
the same number of empty caps should be weighed at the same time
and the moisture figure corrected accordingly.
ANALYSIS OF SINGLE PRIMERS.
If single primers contain a mercury fulminate, antimony sulphide,
and potassium chlorate mixture only, the charge of about 0.02 gram
is too small to give good results with the average quantitative
methods.
Brownsdon 15 developed a volumetric method for determining mer-
cury fulminate, based on the fact that sodium thiosulphate reacts
with mercury fulminate to form free sodium hydroxide, which may
then be titrated with standard acid which is suitable for use here.
In order to standardize the solutions the fulminate is weighed into
a porcelain dish and about 1 gram of sodium thiosulphate in solu-
tion is added. A drop of phenolphthalein indicator is added and the
solution is titrated to slight acidity with N/50 sulphuric acid, after
which back-titration is effected with N/50 sodium hydroxide.
The procedure in the actual analysis is identical. After the
titration is completed, the supernatant liquor is decanted through a
small filter and the antimony sulphide is washed five times with hot
water, the wash water being decanted through the filter each time.
The filter is then dried at 105° C., then the sulphide is dissolved off
with hot concentrated hydrochloric acid. The filtrate is caught in
the porcelain dish containing the bulk of the sulphide residue, and
the dish heated on the water-bath until all of the H,S is driven off.
The solution should not be evaporated to less than 3 c. c. The
solution is transferred to a 100-c. c. Erlenmeyer flask and about 1
gram of tartaric acid added. At this point there should be about 25
c. c. of solution. A drop of phenolphthalein is now added and the
mixture is brought near the neutral point with ammonium hy-
15 Brownsdon, Henry, The proof of percussion caps: Jour. Soc. Chem. Ind., vol. 24,
1905, pp. 381-385,
ANALYSIS OF PERCUSSION PRIMING COMPOSITIONS.
27
droxide. Great care should be taken not to add an excess of am-
monia or the basic chloride will precipitate out and will not go back
into solution if the mixture is again made acid. The solution is
now made neutral by the addition of small amounts of solid sodium
bicarbonate. An excess of 0.5 gram of sodium bicarbonate and 2 c. c.
of clear starch solution are then added and titration with N/100
iodine solution is carried out.
The iodine may be standardized against arsenious oxide. This
is done by weighing arsenious oxide into a porcelain dish, adding
10 c. c. of N/10 sodium hydroxide and a drop of phenolphthalein,
and acidifying with concentrated hydrochloric acid. An excess of
sodium bicarbonate is now added, followed by the starch solution.
The mixture is then titrated with N/100 iodine solution.
The potassium chlorate is figured by difference. If ground glass
is also present, it may be determined by washing, drying, and weigh-
ing the insoluble residue.
By using stronger solutions this procedure may be applied to the
analysis of a composite of charges from several primers.
ANALYSES OF TYPICAL PRIMING MIXTURES.
ANALYSIS OF A PRIMING COMPOSITION CONTAINING FULMINATE, ANTI-
MONY SULPHIDE, CHLORATE, AND GLASS.
The usual type of priming composition contains only four in-
gredients—mercuric fulminate, antimony sulphide, potassium chlo-
rate, and glass-hence its analysis is not difficult and is carried out
in the following manner:
A weighed sample is placed in a beaker and treated with 100 c. c.
of water; 5 c. c. of 1:5 sulphuric acid is added, and the solution
is brought to a boil. Hydrogen sulphide is passed through the solu-
tion for about 30 minutes in order to precipitate the antimony and
mercury.
The beaker and its contents are allowed to cool and the mixture
of sulphides is filtered off. Hydrogen sulphide water is used to
wash the precipitate. The filtrate and wash waters are caught in a
porcelain or silica evaporating dish and evaporated. There should
be present sufficient sulphuric acid to decompose all the chlorate
present. When all the chlorine has been driven off-that is, toward
the end of the evaporation, when the yellowish green color in the
liquid has disappeared-the liquid is transferred to a weighed plati-
num dish. The evaporation of the solution is finished in this dish.
After the residue has been brought to dryness, excess acid is driven
off by stronger heating, and finally the dish and its contents are
strongly ignited with the blast. The factor for the conversion of
potassium sulphate to potassium chlorate is 0.70327.
28
ANALYSIS OF DETONATING AND PRIMING MIXTURES.
The
The filter containing the powdered glass and the mixture of sul-
phides is placed in a beaker and mixed with 5 c. c. of concentrated
hydrochloric acid (1.19) and 2 c. c. of a 50 per cent solution of tar-
taric acid. The mixture is warmed on the water-bath with frequent
stirring until the solids have been thoroughly disintegrated.
beaker is then covered with a watch-glass and 1 c. c. of concentrated
nitric acid is added from a pipette. Warming with stirring is con-
tinued for a short time. The solution is then diluted with a little
water and filtered on an ashless filter. The powdered glass is washed
with hot water, and the filter with its contents is dried, placed in a
weighed porcelain crucible, ignited over a Bunsen burner, cooled,
and weighed.
The filtrate from the powdered glass is heated to boiling and the
mercury and antimony precipitated out with a stream of hydrogen
sulphide for 30 minutes. The beaker and its contents cooled to air
temperature and the sulphides are filtered off on a weighed filter,
the washing being done with hydrogen sulphide water. Either a
porcelain crucible or a silica dish of a capacity of 80 to 100 c. c.,
previously ignited and weighed, is now placed under the funnel.
The antimony sulphide is dissolved out on the filter with ammonium
sulphide and washed down with hot water. If this is done carefully,
the crucible or dish will be only two-thirds full. The mercury sul-
phide remaining on the filter is washed with hot water, alcohol,
ether, and carbon bisulphide, dried at 110° C., and weighed. The
factor for conversion to fulminate is 1.22327. The antimony solu-
tion is evaporated on the water-bath, the residue is oxidized with
concentrated nitric acid (1.42) and taken down two or three times
with fuming nitric acid, and finally ignited carefully over a blast.
The factor for the conversion of antimony oxide to antimony sul-
phide is 1.16716.
ANALYSIS OF A PRIMING COMPOSITION CONTAINING CHLORATE, ANTI-
MONY SULPHIDE, LEAD SULPHOCYANIDE, AND TNT.
This composition is chiefly notable for the reason that it contains
no fulminate. It has been successfully used in military practice.
The method of analysis is as follows:
The TNT is first extracted from a weighed sample with ether.
The sample is dried and reweighed and the loss in weight is taken as
TNT.
The residue is now washed with a water solution of potassium
nitrate, thus dissolving the potassium chlorate and the lead sul-
phocyanide. The loss in weight after drying is recorded. The
residue consists of antimony sulphide and is weighed as such.
The solution containing potassium chlorate and lead thiocyanate
is treated with an excess of N/10 silver nitrate solution, with sub-
ANALYSIS OF PERCUSSION PRIMING COMPOSITIONS.
29
"
sequent heating to the boiling point. After it has stood over night
in a dark place, the silver thiocyanide is filtered on a dried and tared
Gooch filter, dried at 100° C., and weighed. The factor for con-
version to lead thiocyanate is 1.03635.
The filtrate and wash waters are combined and 5 c. c. of 40 per cent
formaldehyde and several of nitric acid are added. The chlorate is
then reduced to chloride by boiling. The chloride formed is deter-
mined by weighing the precipitated silver chloride.
ANALYSIS OF A PRIMING COMPOSITION CONTAINING RED PHOSPHORUS,
LEAD PICRATE, AND BARIUM NITRATE.
A weighed sample of the primer is transferred to a beaker and
treated with distilled water, which dissolves the barium nitrate and
some of the lead picrate. A large excess of hydrochloric acid is now
added, completing the solution of the lead picrate.
The mixture is filtered on a dried and tared filter, and the residue
of red phosphorus washed with water. The filter is then dried at
70° C. and weighed, the weight of the residue being taken as red
phosphorus.
The lead is precipitated from the acid filtrate and wash 'waters
with a stream of hydrogen sulphide. The use of paper pulp is ad-
vised, as this assists coagulation of the lead sulphide. After the
mixture has been brought to the boiling point, it is cooled, then
filtered, and the lead sulphide washed with hydrogen-sulphide water.
Barium is precipitated from the filtrate and wash water with sul-
phuric acid. The factor for the conversion of barium sulphate to
barium nitrate is 1.1197.
If it is desired to check the lead, the lead sulphide is dissolved in
nitric acid and precipitated as sulphate.
ANALYSIS OF A PRIMING COMPOSITION CONTAINING POTASSIUM CHLORATE,
ANTIMONY SULPHIDE, LEAD NITRATE, AND TNT.
A weighed sample of the primer is first extracted with ether, which
removes the TNT. The loss in weight is taken as representing this
constituent.
The residue is then extracted with water, which dissolves out the
chlorate and the lead nitrate. After it has been dried the residue
is weighed and regarded as antimony sulphide. If desired, this may
be checked by dissolving the residue in hydrochloric and tartaric
acids, precipitating the sulphide, igniting to oxide, and weighing as
such.
On account of the fact that only a very small sample is usually
available, but one determination can be made on the chlorate-lead
nitrate solution, the other compound being found by difference.
Lead may be precipitated as sulphate, chlorate determined as chlo.
30
ANALYSIS OF DETONATING AND PRIMING MIXTURES.
ride after reduction by formaldehyde, or potassium determined by
one of several methods. This choice rests with the individual an-
alyst, but probably the simplest method is to determine chlorate by
titration as chloride as previously directed in this paper (see p. 18).
After calculation to chlorate, the lead nitrate is found by difference.
ANALYSIS OF A PRIMING COMPOSITION CONTAINING POTASSIUM CHLORATE,
ANTIMONY SULPHIDE, LEAD NITRATE, TNT, AND GLASS.
The analysis of this composition is carried out in exactly the same
manner as that outlined for the composition containing all these
ingredients except powdered glass, with the following exception:
After the priming composition is washed with potassium nitrate
solution, the insoluble residue will consist of glass and antimony sul-
phide instead of the sulphide alone. This is dried and weighed.
The sulphide is then dissolved out with hydrochloric and tartaric
acids and the glass residue washed with hot water, ignited, and
weighed. The loss in weight may be taken as antimony sulphide,
but if it is desired to check this the antimony may be precipitated
from the filtrate and determined as already described.
ANALYSIS OF A PRIMING COMPOSITION CONTAINING FULMINATE, LEAD
PICRATE, ANTIMONY SULPHIDE, BARIUM NITRATE, AND BARIUM CHLO-
RATE.
A weighed sample of the priming composition is given a wash
with water to dissolve out the barium nitrate, the solution being de-
canted into a filter. The residue is next given several washes with
dilute hydrochloric acid (30 per cent), these also being decanted into
the filter. Everything but the antimony sulphide should now be
completely in solution. This latter is put into solution with hydro-
chloric and tartaric acids and added to the combined filtrates pre-
viously obtained.
The lead, mercury, and antimony are now precipitated from a
slightly acid solution with hydrogen sulphide. The sulphides are
filtered off and washed on the filter with water containing hydrogen
sulphide.
The barium in the filtrate is determined by precipitation with sul-
phuric acid, the resultant barium sulphate being weighed up. BaSO
X1.1197 Ba(NO3) 2.
The mixture of sulphides is removed to a beaker and treated with
nitric acid of specific gravity 1.2. The whole is warmed and the
antimony and lead sulphides are dissolved. The mercury sulphide
remaining is filtered off on a tared Gooch filter and washed with
water, alcohol, ether, and carbon bisulphide; dried at 110° C.; and
weighed. The factor for conversion to mercury fulminate is 1.22327.
ANALYSIS OF PERCUSSION PRIMING COMPOSITIONS.
31
The filtrate containing the antimony and lead is treated with a
little sulphuric acid and evaporated until dense fumes of sulphur
trioxide are given off. It is allowed to cool, then diluted with several
times its volume of water. The lead sulphate settles out on standing,
and is filtered off, dried, and weighed. PbSO,×2.2469=[C¸H₂
(NO₂)¸O]¿Pb.H₂O.
The antimony in the filtrate is thereupon precipitated with
hydrogen sulphide, filtered, washed, ignited to oxide, cooled, and
weighed. The factor for conversion of the oxide to sulphide is
1.16716.
Barium carbonate is used in this mixture in a small amount and
merely as an antacid, hence it is not necessary to make a quantita-
tive determination of this ingredient.
ANALYSIS OF A PRIMING COMPOSITION CONTAINING SILVER PERMANGA-
NATE, ANTIMONY, SULPHIDE, TNT, AND RED PHOSPHORUS.
A weighed sample of the priming composition is extracted with
ether, the loss in weight being taken as TNT. The dried and
weighed residue is treated with water, which dissolves out the silver
permanganate. About 100 c. c. of water, which will dissolve about
a gram of the salt at room temperature, should be used. The loss
in weight may be checked by precipitation of the silver as chloride
or by titration in hot solution of the permanganate radical with
standardized oxalic acid in the presence of sulphuric acid.
The weighed residue is now treated with hydrochloric acid and a
50 per cent solution of tartaric acid, which dissolve out the antimony
sulphide. The residue is dried and weighed, its weight being taken
as red phosphorus. The loss in weight is taken as antimony sul-
phide, but this may be checked by precipitation with hydrogen sul-
phide and ignition to oxide if desired.
ANALYSIS OF A COMPLEX NONCORROSIVE PRIMING COMPOSITION.
A number of noncorrosive priming compositions have been evolved.
Between them they contain the following ingredients:
Mercury fulminate (Hg(ONC)2).
Barium carbonate (Ba(NO3)2).
Lead chromate (PbCrO4).
Powdered glass.
Picric acid (C6H2 (NO2)3OH).
Barium carbonate (BaCO3).
Antimony sulphide (Sb₂S3).
Lead peroxide (PbO2).
Potassium silicate (KSiO3).
No one primer contains all of these substances. What is present is
first determined qualitatively. Outlines for the analysis of a typical
composition follows:
ANALYSIS OF A PRIMING COMPOSITION CONTAINING FULMINATE, ANTI-
MONY SULPHATE, BARIUM NITRATE, PICRIC ACID, AND GLASS.
A weighed sample is transferred to a weighed filter or crucible and
extracted with absolute ether, which removes the picric acid. The
32
ANALYSIS OF DETONATING AND PRIMING MIXTURES.
residue is dried at 50° C., cooled, and weighed. The loss in weight
is taken as picric acid. The ether-picric acid solution may be
evaporated to dryness with desiccated air and identification tests,
such as determination of the melting point and the nitrogen content,
made on the solid picric acid.
The dried residue is now washed with water, thereby dissolving the
barium nitrate and some of the fulminate. The filtrate and wash
waters are made up to volume and aliquoted. Barium is deter-
mined on one portion by precipitation as sulphate, which is calcu-
lated back to the nitrate. The factor for this conversion is 1.1197.
Fulminate dissolved is determined upon another portion by precipi-
tation from ammoniacal solution with hydrogen sulphide.
The residue after the water extract is transferred to a beaker and
treated with 100 c. c. of water and 5 c. c. of 1:5 sulphuric acid.
The mercury and antimony are then thrown out as sulphides with
hydrogen sulphide. These are redissolved by the addition of 5 c. c.
of hydrochloric acid and 2 c. c. of a 50 per cent solution of tartaric
acid. The mixture is warmed on the water bath with frequent.
stirring until the solids have been disintegrated. The beaker is then
covered with a watch glass and 1 c. c. of concentrated nitric acid is
added from a pipette. Warming with stirring is continued for a
short time. The solution is then diluted with a little water and
filtered with an ashless filter. The powdered glass is washed with
hot water and ignited in a weighed porcelain crucible.
The filtrate from the powdered glass is heated to boiling and the
mercury and antimony precipitated out with a stream of hydrogen
sulphide for 30 minutes. The beaker and its contents are allowed to
cool to air temperature and the sulphides are filtered off on a weighed
filter, the washing being done with hydrogen sulphide water. An
80 to 100 c. c. porcelain crucible or a silica dish of the same capacity,
previously ignited and weighed, is now placed under the funnel.
The antimony sulphide is dissolved out on the filter with ammonium
sulphide and washed down with hot water. If this is done carefully,
the crucible or dish will be only two-thirds full. The mercury sul-
phide remaining on the filter is washed with hot water, alcohol, ether,
and carbon bisulphide, dried at 110° C., and weighed. The factor
for conversion to fulminate is 1.22327. The antimony solution is
evaporated on the water bath; the residue is oxidized with concen-
trated nitric acid (1.42), taken down two or three times with fum-
ing nitric acid, and, in conclusion, carefully ignited over a blast lamp.
The factor for the conversion of antimony trioxide to antimony sul-
phide is 1.1671-6.
PUBLICATIONS.
33
PUBLICATIONS ON INVESTIGATIONS OF EXPLOSIVES.
A limited supply of the following publications of the Bureau
of Mines has been printed and is available for free distribution until
the edition is exhausted. Requests for all publications can not be
granted, and to insure equitable distribution applicants are requested
to limit their selection to publications that may be of especial in-
terest to them. Requests for publications should be addressed to the
Director, Bureau of Mines.
The Bureau of Mines issues a list showing all its publications
available for free distribution as well as those obtainable only from
the Superintendent of Documents, Government Printing Office, on
payment of price of printing. Interested persons should apply to
the Director, Bureau of Mines, for a copy of the latest list.
PUBLICATIONS AVAILABLE FOR FREE DISTRIBUTION.
BULLETIN 48. The selection of explosives used in engineering and mining
operations, by Clarence Hall and S. P. Howell. 1914. 50 pp., 3 pls., 7 figs.
BULLETIN 59. Investigations of detonators and electric detonators, by Clarence
Hall and S. P. Howell. 1913. 73 pp., 7 pls., 6 figs.
BULLETIN 96. The analysis of permissible explosives, by C. G. Storm. 1916.
88 p., 3 pls., 7 figs.
TECHNICAL PAPER 7. Investigations of fuse and miners' squibs, by Clarence
Hall and S. P. Howell. 1912. 19 pp.
TECHNICAL PAPER 17. The effect of stemming on the efficiency of explosives,
by W. O. Snelling and Clarence Hall. 1912. 20 pp., 11 figs.
TECHNICAL PAPER 78. Specific-gravity separation applied to the analysis of
mining explosives, by C. G. Storm and A. L. Hyde. 1914. 14 pp.
TECHNICAL PAPER 125. The sand test for determining the strength of detona-
tors, by C. G. Storm and W. C. Cope. 1916. 68 pp., 2 pls., 5 figs.
TECHNICAL PAPER 145. Sensitiveness to detonation of trinitrotoluene and
tetranitromethylaniline, by G. B. Taylor and W. C. Cope. 1916. 11 pp., 1 pl.
TECHNICAL PAPER 160. The determination of nitrogen in substances used in
explosives, by W. C. Cope and G. B. Taylor. 1917. 46 pp., 4 figs.
TECHNICAL PAPER 162. Initial priming substances for high explosives, by
G. B. Taylor and W. C. Cope. 1917. 32 pp.
TECHNICAL PAPER 234. Sensitiveness of explosives to frictional impact, by
S. P. Howell. 1919. 17 pp., 2 pls., 1 fig.
TECHNICAL PAPER 243. Development of liquid-oxygen explosives during the
war, by G. S. Rice. 1920. 46 pp., 2 pls., 6 figs.
FUPLICATIONS THAT MAY BE OBTAINED ONLY THROUGH THE SUPERIN-
TENDENT OF DOCUMENTS.
BULLETIN 51. The analyses of black powder and dynamite, by W. O. Snelling
and C. G. Storm. 1913. 80 pp., 5 pls., 5 figs. 10 cents.
BULLETIN 66. Tests of permissible explosives, by Clarence Hall and S. P.
Howell. 1913. 313 pp., 1 pl., 6 figs. 25 cents.
TECHNICAL PAPER 12. The behavior of nitroglycerin when heated, by W. 0.
Snelling and C. G. Storm. 1912. 14 pp., 1 pl., 2 figs. 5 cents.
TECHNICAL PAPER 146. The nitration of toluene, by E. J. Hoffman. 1916. 32
pp. 5 cents.
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