Year: 1896

page_text: I, GEORGE BENEKÉ, of 13, Hesketh Street, Southport, in the County of Lancashire,
Gentleman, do hereby declare the nature of this invention to be as follows:-
This invention consists in an improved manufacture of explosives from nitrate of
ammonium and resin, in the latter of which is incorporated carbonate or bicarbonate
of sodium or potassium, together with chromate or bichromate of sodium or
potassium.
From nitrate of ammonium and bodies of a resinous or hydro-carbon nature, either
with or without the addition of chromates or other oxidising materials, a number of
so-called "safety explosives" have been of late years prepared, in all of which special
attention has been paid to the physical conditions of the various ingredients and to
their method of mixture as constituting a critical and essential feature in the keeping
qualities, safety and explosive force of the preparation.
I have discovered that better effects may be produced by incorporating into the
mixture, together with chromates or bichromates, a small proportion of carbonate
or bicarbonate of potassium or sodium, which has the effect of smothering all flame
on detonation, thereby increasing the safety of the explosive, and also of giving the
explosive a more rending and less pulverising action, which is of great importance
in coal mining.
In order to incorporate the carbonate or bicarbonate into the mixture I have
however to proceed in a particular manner, otherwise the addition increases the
hygroscopicity of the mixture to such an extent that it speedily liquefies and becomes
unfit for use.
In order to carry out my invention I therefore melt 5 parts of resin, taking care
that the temperature is not raised much above the melting point of the resin, and
when reduced to a fluid state I stir into it 2 parts of potassium bichromate and
parts of sodium carbonate or its equivalent of sodium bicarbonate, potassium
carbonate or potassium bicarbonate. I do not confine myself to these proportions,
and may increase the proportion of bichromate to about 3 parts and of the carbonate
to 1 parts, but I prefer to keep within these limits. The mixture is maintained
just above the melting point of the resin and constantly stirred until the ingredients
have been uniformly mixed, when the melt presents a dull yellow colour according
to the quality of resin employed. The mixture should not however become green
and dark which is a sign of overheating.
The mixture is then allowed to cool and ground to an extremely fine powder,
which its extremely brittle character and absence of hygroscopic properties renders
very easy. To 8 or 10 parts of this powder I then add about 90 or 92 parts of
ammonium nitrate which must have been previously dried, ground to an extremely
fine powder, and again heated for about 2 hours at a temperature of 1000 C to drive
off the last traces of moisture. The mixture of the resinous powder should be made
in a revolving drum with the ammonium nitrate direct as it comes from the drying
oven and whilst still hot. In this way a more uniform mixture and better aggregation

page_text: of the particles of the ingredients is effected, whilst in order to ensure the absence
of moisture it is preferable before packing the explosive or making up into cartridges
to again heat the powder in a steam jacket to about 80° C.
I, GEORGE BENEKE, of 13 Hesketh Street, Southport, in the County of Lancashire,
Gentleman, 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 :-
This invention consists in an improved manufacture of explosives from nitrate of
ammonium and resin, in the latter of which is incorporated carbonate or bicarbonate
of sodium or potassium, together with chromate or bichromate of sodium or
potassium.
From nitrate of ammonium and bodies of a resinous or hydrocarbon nature, either
with or without the addition of chromates or other oxidizing materials, a number of
so-called "safety explosives" have been of late years prepared, in all of which special
attention has been paid to the physical conditions of the various ingredients and to
their method of mixture, as constituting a critical and essential feature in the
keeping qualities, safety and explosive force of the preparation.
I have discovered that better effects may be produced by incorporating into the
mixture together with chromates or bichromates, a small proportion of carbonate or
bicarbonate of sodium or potassium, which has the effect of sinothering all flame on
detonation, thereby increasing the safety of the explosive, and also of giving the
explosive a more rending and less pulverizing action, which is of great importance
in coal mining.
In order to incorporate the carbonate or bicarbonate into the mixture I have,
however, to proceed in a particular manner, otherwise the addition increases the
hygroscopicity of the mixture to such an extent that it speedily liquefies and becomes
unfit for use. The features of my invention are the introduction of carbonate or
bicarbonate of sodium or potassium into an explosive compound in addition of
chromate or bichromate of sodium or potassium resin and ammonium nitrate, the
carbonate or bicarbonate of sodium or potassium being introduced together with the
chromate or bichromate of sodium or potassium into the resin in a melted state prior
to the incorporation of the resin with the ammonium nitrate.
Having stated the nature of my invention, I will further illustrate it by giving the
following example, but I premise that this may be varied in its details without
departing from my invention.
In order to carry out my invention, I melt 5 parts of resin, taking care that the
temperature is not raised much above the melting point of the resin, and when
reduced to a fluid state, I stir into it 2 parts of potassium bichromate (or
its equivalent quantity of potassium chromate or sodium chromate or
bichromate), and part of sodium carbonate (or the equivalent weight
of sodium bicarbonate, potassium carbonate or potassium bicarbonate). I do not
confine myself to these proportions, and may increase the proportion of potassium
bichromate to about 3 parts and the proportion of the sodium carbonate to 1 parts,
but I prefer to keep within these limits. The mixture is maintained just above the
melting point of the resin and constantly stirred until the ingredients have been
uniformly mixed, when the melt presents a dull yellow color according to the quality

page_text: of resin employed. The mixture should not however become green and dark, which
is a sign of overheating.
The mixture is then allowed to cool, and ground to an extremely fine powder,
which its extremely brittle character and absence of hygroscopic properties renders
very easy. To 8 or 10 parts of this powder I then add about 90 or 92 parts of
ammonium nitrate which must have been previously dried, ground to an extremely
fine powder, and again heated for about 2 hours at a temperature of 100° C. to drive
off the last traces of moisture. The mixture of the resinous powder should be
made in a revolving drum with the ammonium nitrate direct as it comes from the
drying oven and whilst still hot. In this way a more uniform mixture and better
aggregation of the particles of the ingredients is effected, whilst in order to ensure
the absence of moisture it is preferable before packing the explosive or making up
into cartridges to again heat the powder in a steam jacket to 70° C a temperature
insufficiently high to melt the resin or render it sticky.
The explosive manufactured as described above should be hermetically closed in
cartridges or otherwise.
It is specially suitable for blasting rock and stone in coal mines where coal dust and
pit gas abound; it will not ignite them, and is a most powerful explosive and quick
in its action.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I Claim is
1. The process of manufacture of explosives composed of sodium or potassium
carbonate or bicarbonate, sodium or potassium chromate or bichromate, resin, and
ammonium nitrate, consisting in incorporating sodium or potassium carbonate or
bicarbonate together with sodium or potassium chromate or bichromate with resin in
a melted state, allowing to cool and grinding to powder the mixture so obtained, and
subsequently incorporating the ground mixture with ammonium nitrate, substantially
as described.
2. In the manufacture of explosives in which ammonium nitrate, resin, sodium or
potassium chromate or bichromate are employed, the method of incorporating
carbonate of soda or other flame reducing metallic salts with resin in a melted state
prior to its incorporation with ammonium nitrate, substantially as described.
3. In the manufacture of explosives composed of sodium or potassium carbonate
or bicarbonate, sodium or potassium chromate or bichromate, resin, and ammonium
nitrate, the use of sodium or potassium carbonate or bicarbonate substantially as
described.
4. The herein described explosives composed of sodium or potassium carbonate or
bicarbonate, sodium or potassium chromate or bichromate, resin, and ammonium
nitrate.
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J. C. MEWBURN & ELLIS,
55 and 56,Chancery Lane, London, Chartered Patent Agents.