Manufacture of Explosives.
Year: 1893

page_text: CONTUMIE SIMALFICATION.
[Communicated from abroad by WESTFALISCH-ANHALTISCHEN SPREUGSTOFf
ACTIEN GESELLSCHAFT, in Coswig, in Anhalt, German Empire.]
Manufacture of Explosives.
I, OLIVER IMRAY, of No. 28, Southampton Buildings, Chancery Lane, in the
County of London, Chartered Patent Agent, do hereby declare the nature of
this invention and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement :-
The present invention refers to the manufacture of explosives from alkali nitrates
and resins.
My foreign correspondent has found that a very serviceable explosive,
which may be used to great advantage especially in collieries, can be made out of
the two bodies above mentioned if both be intimately mixed together. This is
accomplished by pouring the alkali nitrate, preferably ammonium nitrate, in a dry
state, granulated or in powder along with a solution of resin into a suitable fluid
medium, and grinding the mixture in a ball mill or by stampers so as to reduce the
ammonium nitrate to an extremely fine impalpable powder, and mix it intimately
with the resinous solution. To make a serviceable explosive, it is absolutely
necessary that the ammonium nitrate should be ground after the resinous solution
has been poured over it. Then will be noticed a phenomenon which can be
observed in other grinding processes, and particularly in ball mills, namely that, if
the material be wetted with a solution that does not dissolve it, a greater degree of
fineness of reduction can be obtained than if it were attempted to grind the material
in a dry state. If, for the purpose of wetting the alkali nitrate I use, as is the case
in this process, a solution of the resin in a liquid, in which the alkali nitrate is not,
or scarcely at all soluble, I obtain, not only a finer reduction of the nitrate, but also
the further advantage that, with the process of reduction the thorough admixture is
also effected. When after grinding, the solvent is eliminated by heating the
mixture, I obtain an extremely homogeneous and effective explosive which may be
farther ground, or may be at once used to make cartridges. If the ammonium
nitrate were ground in a dry state, and subsequently mixed with powdered resin or
with a resinous solution, without then subjecting it to grinding, a very much weaker
explosive would be obtained by reason of the incompleteness of the comminution of
the nitrate. The ammonium nitrate wetted with alcohol might first be ground and
then mixed with the resinous solution poured on it, but, though the comminution of
the nitrate might be sufficient, it would be impossible thus to obtain so intimate a
mixture of the two substances as when the resinous solution itself is used for wetting
the nitrate, so that the grinding and mixing are carried on simultaneously.
Among resinous substances, those only can be used to advantage which present a
character of brittleness. From observations made with soft and hard resins it has
been found that, when hard resins are used, ignition is propogated far more rapidly
through the explosive than when soft and plastic bodies such as wax, paraffin or the
like are employed, and consequently the blasting power is greater. The following
resinous substances may be used, colophon, hard pitch, asphalt and the like, and, as
solvents, alcohol, benzine, ether, carbon bisulphide and the like.
For manufacturing the explosive the following process may be followed. A
solution of 6 parts of resin in 3 parts of alcohol, benzine or the like is poured
over 90 parts of ammonium nitrate coarsely granulated or previously pulverised,
and the mixture is worked for one to two hours in a ball mill. The nitrate is thus
quite comminuted and at the same time becomes intimately mixed with the resinous
solution, so that a homogeneous mass is produced. After grinding, the mixture is
heated for the purpose of vaporising the solvent, and can then, after further
grinding, be put direct into cartridges.

page_text: Experience has shewn that the best solvents for the resin are fluids containing
nitric esters and more particularly nitric ethyl ester, nitric methyl ester, and nitric
anyl ester. These nitric esters slightly nitrate the organic substance, so that the
explosive effect is heightened without, however, producing much flame. These
nitric esters can be mixed with alcohol, benzine, etc., in the proportion of about
10 parts ester to about 90 parts of the spirit.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
1. In the manufacture of explosives from alkali nitrate and solutions of brittle
resin, subjecting the nitrate after its impregnation with the resinous solution, to a
grinding process so as to obtain thorough comminution of the nitrate and its
intimate mixture with the resinous solution.
2. In the manufacture above referred to, the use of nitric esters such as nitric
ethyl ester, nitric methyl ester and nitric amyl ester in admixture with the resin
solvent.
Dated this 16th day of August 1803
ABEL & IMRAY,
Agents for the Applicant.