The present invention relates to improved water-in-oil emulsion explosive compositions and a
process for the preparation thereof.More particularly ,the invention relates to the use of such
improved water-in-oil.emulsion explosive compositions in plastic shells provided with tunnels to
facilitate use of detonators/detonating cord,commonly called in commercial mining explosives
industry parlance as boosters.
The basic object of the present invention is to provide a safer booster comprising of water-in-oil
emulsion explosive composition for the purposes of boosting a "column charge" of explosive.This
is traditionally achieved by the use of "Cast Boosters" made using a mixture of high explosives
such as PETN and TNT and which suffer from the disadvantage of high impact friction
sensitivity.(See Table 1 & 2 for comparitive data)
A more specific object of the invention lies in the provision of an improved water-in-oil emulsion
explosive composition in which the fuel forming the continuous phase or the bilayer leads to
improved refinement of the "oxidiser" microdroplets leading to greater stability and the right
rheology for packaging in plastic shells.
A still more specific object of the invention resides in a water-in-oil composition which possesses
the desired properties such as viscosity, Velocity of detonation ,sensitivity to commercial detonators
or detonating cords as well as the non-electric detonators.
A further object resides in a method for the manufacture of the improved water-in-oil emulsion
explosive composition described herein.
Towards achieving the objects of the invention, the applicants have investigated several types of
fuels. This investigation has revealed that the fuel best suited for the purpose is a combination of
paraffinic hydrocarbons with a polymeric additive commonly referred to as Holt Melt Adhesive
The great advantage of this fuel is that it leads to high refinement of the oxidiser microdroplets
without affecting their stability by preventing coalescence of the droplets.
Accordingly the present invention provides an improved water-in-oil emulsion explosive
composition which comprises on a percentage by weight basis from 70 to 90% of one or more
inorganic pxidiser salts such as herein described ,from 3 to 8% of atleast one fuel comprising
paraffinic hydrocarbons along with additives and from 2 to 5% of emulsiriers such as nereui
described.
The inorganic oxidiser salts, which in the aqueous solution constitute the disperse phase of the
improved water-in-oil emulsion explosives compositions of the present invention are selected from
ammonium nitrate, alkali metal nitrates such as sodium nitrate or potassium nitrate and alkaline
earth metal nitrates such as Calcium Nitrate The aqueous solution can comprise of any of these
nitrates in combination but the preferred oxidiser salt is ammonium nitrate.
In addition the oxidiser solution also comprises about 4-10% of a chemical sensitiser such as
perchlorate salts of sodium,potassium or ammonium..
Preferably the water content of the aqueous solution of inorganic oxidiser salts comprises from 8 to
14% by weight based on the total weight of the explosive composition.
The emulsifiers employed in the composition of the present, invention impart to
the emulsified composition structure a high degree of stability. These include
the particularly preferred condensation product of polyisobutylene surface
active agent and an alkanlolamine under the code name E-475/476 and is
present in an amount of 0.5 to 3 % and preferably in the range of I to 2%.
Other emulsifiers include polymers prepared by the condensation of long chain
aliphatic carboxylic acids with polyethlene glycols of molecular weight between
400 and 3000, esters of Sorbitol with long chain fatty acids such as Sorbitan
Monooleate (SMO), Sorbitan trioleate (STO) or Sorbitan sesquioleate (SSO),
phospholipids such as Soyalecithin (SL) or Oxaziline or imidazoline derivatives
thereof, lanolin, a steroidal product obtained from wool fat or phosphoric acid
esters and also other paraffinic fuel-compatible surfactants available under
different brand names.
The improved emulsion explosive composition of the present invention can
preferably incorporate in addition to the constituents mentioned above one or
more of the carbonaceous fuels such as microcrystalline wax, slack wax,
paraffin wax, montan wax, bees wax, agro wax, ozokerite, diesel fuel, tall oil and
other hydrocarbon fuels containing paraffinic hydrocarbons, aromatic
hydrocarbons, olefinic hydrocarbons or nitrocarbons.
In addition for increased energy of the water-in-oil emulsion explosives
composition of the present invention, one or more of the known metallic fuels
such as aluminium, ferrosilicon etc are uses to the extent of 3 to 7%.
The present invention also provides a process for the preparation of an
improved water-in-oil emulsion explosive composition capable of substituting
hazardous high explosive based cast boosters in the market, which comprises
forming an aqueous solution of one or more inorganic oxidiser salts such as
herein described in addition to a chemical sensitiser forming separately a blend
of at least one fuel comprising Paraffinic hydrocarbons with hot melt adhesive
and one or more emulsifiers such as herein described, combining said solution
and said blend and subjecting the mixture to emulsification.
Preferably the aqueous solution of the oxidiser salts is maintained at a
temperature of 70-90°C while the emulsifer-fuel blend is maintained at 70-80°C
before being fed for emulsification to an emulsification apparatus. The
apparatus can be either a continuously fed orifice based cylindrical chamber or
a ribbon blender with variable speed drive.
The sensitivity to the emulsion explosive composition is provided by the
incorporation of physical voids such as Expanded polystyrene, glass
microballons or Perlite. These physical voids constitute 2- 6% of the said
emulsion explosive composition and incorporation is done by shearing action in
order to disperse the material properly and uniformly.
Finally the emulsion explosive is cartridged in either rigid paper shells or plastic
shell in weights varying from 100 gms to 250 grns depending upon the end use.
Special care is taken to ensure complete filling of the shells and also to keep the
channels intended for introduction of the cord/detonators free of explosive.
The improved water-in-oil emulsion explosive composition so made has been
tested for its comparative boosting capabilities by an independent explosive
evaluation agency, CMPDI, Ranchi and found to be comparable to commercially
available cast boosters with better safety characteristics.

It must be borne in mind that the embodiment of the present invention is merely illustrative of the
process of the present invention which is not limited to only the specific examples mentioned
herein. Additional embodiments of the invention are possible within the scope of what has been
described herein
WE CLAIM: -
1. An improved water-in-oil emulsion explosive composition tor use
boosters cartridged in plastic shells which comprises 70 to 90% by weight of an
aqueous solution of inorganic oxidiser salts such as herein described, from 3 to
8% by weight of a fuel phase and from 3 to 7% by weight of one or more solid
metallic fuels.
2. A composition as claimed in claim 1 wherein said oxidiser salts are
selected from ammonium nitrate or alkali and alkaline earth metal nitrates or
erchlorate salts of Sodium, Potassium or Ammonium.
3. A composition as claimed in claim 1 wherein said metallic fuels are
selected from aluminium, ferrosilicon and silicon.
4. A composition as claimed in claims 1 and 3 wherein the solid metallic fuel
is present in an amount from 3 to 10% by weight preferably from 3 to 7%
5. A composition as claimed in any preceding claim wherein the water
content of the said composition is in the range of 8 to 14% by weight.
6. A composition as claimed in any preceding claim wherein said organic fuel
comprises one or more member selected from the group consisting of
carbonaceous fuels such as microcrystalline wax, slack wax, paraffin
wax.montan wax.bees wax, agro wax, ozokerite, diesel oil, paraffin oil, tall oil,
and other hydrocarbon fuels containing paraffinic hydrocarbons, olefininc
hydrocarbons or nitrocarbons in addition to an additive called Hot Melt,
adhesive.
7. A composition as claimed in claim 1 and 6 wherein the fuel is in the range
of 3 to 8% and the hot melt adhesive varies from 1 to 3%.
8. A process for the manufacture of an improved water-in-oil emulsion
explosive composition as claimed in any preceding claim which comprises
forming in any known manner an aqueous solution of one or more inorganic
oxidiser salts such as herein described, combining in any known manner said
aqueous solution with a blend of atleast one fuel and emulsuying in any known
manner, said mixture, to obtain said emulsion explosive composition to which
one or more solid metallic fuels are combined in any known manner, which said
aqueous solution of inorganic oxidiser salt constitutes 70 to 90% by weight said
fuel phase constitutes 3 to 8% by weight and said solid metallic fuels constitute
from 3 to 7% by weight.
9. A process as claimed in claim 9 wherein said oxidiser salts are selected
from ammonium nitrate or alkali/alkaline earth metal nitrates or perchlorate
salts of sodium, potassium or ammonium.
10. A process as claimed in claims 9 and 10 wherein said organic
comprises one or more member selected from the group consistined
carbonaceous fuels such as microcrystalline wax, slack wax, paraffin
montan wax, bees wax, agrowax, ozokerite, diesel oil, paraffin oil, tall oil and
other hydrocarbon fuels containing paraffinic hydrocarbons, aromatic and
hydrocarbons, olefinic hydrocarbons or nitrocarbons.
11. A process as claimed in claims 9 to 11 wherein said blend of atleast one
fuel comprises highly branched paraffinic hydrocarbon and a polymeric additive
called Hot Melt adhesive and one or more conventional emulsifiers of the kind
such as herein described.
12. A process as claimed in any one of claims 9 to] 11 wherein said
emulsification is carried out in the presence of emulsifier comprising one or
more members selected from the group consisting of condensation products of
polyisobutylene surface active agent and alkanolamines and long chain
aliphatic carboxylic acids with polyethylene glycol of molecular weight between
400 and 3000, esters of sorbitol with long chain fatty acids such as sorbitan
monooleate (SMO), sorbitan trioleate (STO) or sorbitan squioleate (SSO),
phospholipids such as soyalecithin (SL) or oxazoline or imidazoline derivatives
thereof, lanolin, a steroidal product obtained from wool fat or phosphoric acid
esters and also other paraffinic fuel compatible surfactants available under
different brand names.
13. A process as claimed in any preceding claims 9 to 13 wherein said
emulsification is carried out in the presence of density reducing agents or
physical voids.
14. An improved water-in-oil emulsion explosive composition substantially
as herein described with reference to the foregoing examples.
15. A process for the manufacture of an improved water-in-oil emulsion
explosive composition substantially as herein described with reference to the
foregoing examples.

An improved water-in-oil emulsion explosive composition tor use
boosters cartridged in plastic shells which comprises 70 to 90% by weight of an
aqueous solution of inorganic oxidiser salts such as herein described, from 3 to
8% by weight of a fuel phase and from 3 to 7% by weight of one or more solid
metallic fuels.