BOUE EXPLOSIVE

SLURRY EXPLOSIVE

Abrégé anglais

ABSTRACT OF THE DISCLOSURE
A gel-type explosive having enhanced storage sta-
bility is provided. It includes a solid explosive material
(e.g. T.N.T., PETN, RDX or pentolite) dispersed within a
gel-type slurry containing antifreeze components (e.g.
urea, formamide and ethylene glycol) and at least 1.25%
by weight guar as a thickner.

Revendications

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. An explosive composition comprising a solid
explosive material dispersed within a gel-type slurry,
said gel-type slurry containing antifreeze components and
at least 1.25% by weight of guar gum as a thickener.
2. The explosive composition of claim 1 wherein
said slurry includes nitrate salts therein.
3. The explosive composition of claim 2 wherein
said nitrate salts comprise ammonium nitrate, sodium nitrate
and calcium nitrate.
4. The explosive composition of claim 3 comprising
24 - 34% by weight ammonium nitrate, 4 - 6% by weight sodium
nitrate and 13 - 19% by weight calcium nitrate.
5. The explosive composition of claim 4 compris-
ing 29% by weight ammonium nitrate, 5% by weight sodium
nitrate and 16% by weight calcium nitrate.
6. The explosive composition of claim 1 wherein
the anitfreeze comprises urea, formamide and ethylene gly-
col.
7. The explosive composition of claim 5 wherein
the antifreeze comprises 2.0 - 2.8% by weight, urea, 2.0-
2.8% by weight formamide and 4 - 6% by weight ethylene gly-
col.
8. The explosive composition of claim 7 comprising
2.4% by weight urea, 2.4% by weight formamide and 5% by
weight ethylene glycol.
9. The explosive composition of claim 1 wherein
the solid explosive is T.N.T., PETN, RDX, pentolite or tetryl.

10. The explosive composition of claim 9 wherein
the solid explosive is T.N.T.
11. The explosive composition of claim 10 wherein the
T.N.T. is present in an amount of 22 - 30% by weight.
12. The explosive composition of claim 11 wherein
the T.N.T. is present in an amount of 26% by weight.
13. The explosive composition of claim 1 including
lead azide or potassium pyroantimonate as a detonator.
14. An explosive composition comprising in per cent
by weight:
ammonium nitrate, 29
sodium nitrate, 5
calcium nitrate, 16
urea, 2.4
formamide, 2.4
ethylene glycol, 5
TNT, 26
water, 12
potassium
pyroantimonate, 0.01
and guar, 1.25
and having a pH of 4.4.

Description

1053470
The present invention relates to explosive compo-
sitions. It relates more $pecifically to such explosive
compositions which are of the slurry type, and which also
have good storage stability under adverse conditions.
Gelatinous and semi-gelatinous high explosives
(which are known as gelatin dynamites or semi-gelatin dy-
namites) are well known in the art. These are plastic or
cohesive in character and consist of gelatinized explosive
agents. In such gelatinized explosive the gel-phase is
blended with other ingredients including oxidizing agents,
carbonaceous ingredients and the like to form finished
explosive mixtures. (See, for example, Canadian Patent
No. 865,033 issued Mar. 2, 1971 to Neil E. Gehrig, et al,
directed to a gelled nitric acid blasting composition;
Canadian Patent No. 778,709 issued Feb. 20, 1968 to John
A. Arbie dlrected to an ammonium nitrate explosive gel
of improved antifreeze properties; Canadian Patent No.
688,919 issued June 16, 1964 to Alan H.B. Weeks directed
to a gelled explosive CQntaining ammonium nitrate, sodium
20 nitrate, explosive granules and a gelling agent; and Cana-
dian Patent No. 957,152 issued Nov. 5, 1974 to Errol L.
Falconer et al, directed to a gelatinized explosive composi-
tion including lower aliphatic glycols). Such explosives
may be prepared in a wide range of strengths and with a
25 variety of physical characteristics and consequently may
be tailored for specific end uses.
However, a deficiency of these gel-type explosive
compositions is that the degree or extent of cohesiveness
of such mixtures largely depends on the quantity of liquid
30 sensitizer gel-phase present~ Furthermore such slurry

1053470
explosives generally do not have good storage stability.
Accordingly, it is desirable to provide gel-type
explosive which would have enhanced storage stability.
Thus, it would be desirable to provide an improved explosive
for engineering tasks, e.g., for use in mining or blasting
operations at low temperatures where it may be required to
sti~re the explosive over long periods of time.
By a broad aspect of this invention, an explosive
composition is provided comprising a solid explosive ma-
terial dispersed within a gel-type slurry, containing anti-
freeze components and at least 1.25% by weight of guar gum
as a thickness.
In a specific aspect of this invention, the gel-
type slurry includes various antifreeze agents e.g., urea,
formamide and ethylene glycol and a high concentration of
a gelliffg agent e.g., at least 1.25% by weight of guar gum
to provide stability under adverse climatic conditions.
It also typically contains nitrates (e.g., ammonium nitrate,
potassium nitrate, sodium nitrate, calcium nitrate, etc.),
any of the conventional solid explosive materials or boosters
(e.g., T.N.T., PETN, RDX, pentolite, tetryl, etc.).
Thus, the present invention, in one of its main aspects
is based on an increase in the thickener concentration to
at least 1.25% by weight and on the inclusion of certain
antifreeze components.
The novel explosive composition within aspects of
this invention includes a gel-type slurry and a solid explo-
sive and detonator. The gel-type slurry includes nitrate
sa~ts, a thickener, antifreeze agents and water. Generally,
the nitrate salts are present in amounts of from 41 - 59%
by weight, but usually in an amount of 50% by weight. In

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general ammonium nitrate is present in amounts of 24 - 34%
by weight (preferably 29% by weight); sodium nitrate is
present in amounts of 4 - 6% by weight (preferably 5% by
weight); and calcium nitrate is present in amounts of 13 -
19% by weight (preferably 16~ by weight).
The antifreeze components are generally present in
amounts of from 8% to 11% by weight, and preferably in an
amount of 9.8% by weight. In general, each of the urea
and formaldehyde is present in amounts of 2.0 - 2.8% by
weight (preferably 2.4% by weight); and ethylene glycol
in amounts of 4% - 6% (preferably 5% by weight.
The thickener used is guar gum, whose principal
constituent is mannogalactan. The thickener must be used
in an amount of at least 1.25% by weight and up to amounts
of 2.25% by weight.
The final component of the gel-type slurry is water,
which is used in necessary amounts, e.g., from 10% - 15%
by weight. The solid explosive used is TNT, PETN, RDX,
pentolite, tetryl, etc. used in amounts of 22 - 30% by weight,
and preferably in amounts of 26% by weight.
The detonator is a small amount of an easily ex-
plodable charge, e.g., lead azide or potassium pyroanti-
monate. It generally is used in amounts of approximately
0.01% by weight.
The invention in one of its aspects, is exemplified
below:
--4--

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The slurry explosive contained:
% by weight
Nitrate Salts: Ammonium Nitrate 29
Sodium Nitrate 5
Calcium Nitrate 16
Thickener: Guar 1.25 - 2.18
Antifreeze: Urea 2.4
Formamide 2.4
Ethylene Glycol 5
Solid Explosive: T.N.T. 26
Water 12 - 13
Detonator: C-20 (potassium
pyroantimonate) approx. 0.01
It was found that the slurry explosive above de-
scribed has excellent stability. When a similar explosive
composition containing less than 1.25% by weight guar was
tested, it was found to have poor storage stability.