SENSITIZING COMPOSITION FOR ENERGETIC HYDROGEN PEROXIDE EMULSIONS

Abstract

A sensitizing composition for generating gas bubbles in an energetic hydrogen peroxide emulsion is disclosed. The sensitizing composition comprises a liquid carrier, a solid hydrogen peroxide catalyst which is dispersed in the liquid carrier and; a coating agent which is non-soluble in hydrogen peroxide and in water and which is arranged to coat the solid hydrogen peroxide catalyst dispersed in the liquid carrier. A method of preparing such a sensitizing composition is also disclosed.

Claims

1. A sensitizing composition for generating gas bubbles in an energetic hydrogen peroxide emulsion, which sensitizing composition comprises; a liquid carrier; a solid hydrogen peroxide catalyst which is dispersed in the liquid carrier; and a coating agent which is non-soluble in hydrogen peroxide and in water, wherein the coating agent is arranged to coat the solid hydrogen peroxide catalyst dispersed in the liquid carrier.

2. A sensitizing composition according to claim 1, wherein the hydrogen peroxide catalyst comprises a substance selected from the group consisting of: metal powders, metal oxide powders, carbon powders, charcoal powders, graphite powders and cellulose powders.

3. A sensitizing composition according to claim 1, wherein the coating agent comprises a substance selected from the group of: mineral oils, petroleum oils, aromatic oils, bio-oils, synthetic fuel oils, diesel oils, lubrication oils, kerosene oils, naphtha oils, paraffin oils, lubrication oils, chlorinated paraffin oils, micro benzene oils, toluene oil, polymeric oils, rapeseed oils, coconut oils, fish oils, microcrystalline wax, paraffin wax, animal wax, plant wax, montan wax, polyethylene wax, polyethylene derivative wax and aluminium powder.

4. A sensitizing composition according to claim 1, further comprising a surfactant.

5. A sensitizing composition according to claim 1, further comprising an anti-freezing agent.

6. A sensitizing composition according to claim 1, wherein the hydrogen peroxide catalyst is a solid in powder form with a particle size less than 50 micrometre.

7. A sensitizing composition according to claim 1, wherein the hydrogen peroxide catalyst is a water-soluble salt.

8. A sensitizing composition according to claim 1, wherein the hydrogen peroxide catalyst constitutes 0.05-9% by weight of the sensitizing composition.

9. A sensitizing composition according to claim 1, further comprising; an oil component; a water-soluble component; and an emulsifier, wherein the sensitizing composition is prepared as an emulsion.

10. A method of preparing a sensitizing composition for generating gas bubbles in an energetic hydrogen peroxide emulsion, which method comprises dispersing at least one hydrogen peroxide catalyst into a liquid carrier and adding a coating agent which is non-soluble in hydrogen peroxide and in water into the dispersion.

Description

EXAMPLES

[0075] The sensitizing composition is used for generating gas bubbles in an energetic hydrogen peroxide emulsion composition. The sensitizing composition comprises; liquid carrier and a solid hydrogen peroxide catalyst which is dispersed or dissolved in a liquid carrier. A coating agent is arranged to coat a solid hydrogen peroxide catalyst dispersed in the liquid carrier or to increase the viscosity of the emulsion to thereby decrease mass transfer of a hydrogen peroxide catalyst dissolved in the liquid carrier.

[0076] By adding a coating agent, the composition allows for higher control of sensitivity range, densities and gassing time for the hydrogen peroxide emulsion composition. Such to allow for delayed sensitisation and density allowing for initiation with conventional means such as a detonator with or without an amplification charge (known as a primer or booster).

[0077] The sensitizing composition may be prepared by a method comprising dispersing or dissolving at least one hydrogen peroxide catalyst into a liquid carrier and adding a coating agent into the dispersion or solution respectively. The coating agent may be added to the liquid carrier before, during or after dispersing or dissolving the hydrogen peroxide catalyst into the liquid carrier.

[0078] The present invention can be used for a variety of forms of emulsion type explosive compositions provided of course that the principles of the invention as described herein are observed. The formation and use of some exemplifying sensitizing compositions according to the invention are given in examples 1?4 below.

TABLE-US-00001 Example 1 Ratio Substance Function (Weight %) Carbon powder (30 micron) Catalyst 0.6% Xanthan gum Coating agent 1.4% Distilled water Carrier 98%

[0079] The carbon powder was added to the water and then the Xanthan gum was slowly dispersed under mixing. The result was a fluid sensitizing composition in the form of a low viscous black gel in which the carbon powder was suspended. 2% by weight was added and mixed to a high viscous energetic hydrogen peroxide emulsion. The hydrogen peroxide emulsion comprised an oil phase with a mineral oil having a density of 0.83 g/cm.sup.3 combined with one PIBSA type emulsifier and one SMO type emulsifier and the oxidiser phase comprised a hydrogen peroxide and water solution of 49.9% by weight concentration. The emulsion was sensitized in 20 minutes at 14 degrees Celsius. The emulsion was detonated in a 38 mm steel pipe with 2 mm wall thickness using an 8d detonator and the detonation velocity was determined to be approximately 4000 m/s.Math.s The emulsion stayed stable over 30 days in sensitized state.

TABLE-US-00002 Example 2 Ratio Substance Function (Weight %) Carbon powder (30 micron) Catalyst 0.5% Polycarboxylate thickener Coating agent 0.6% Distilled water Carrier 98.4% Phosphonic acid pH modifier 0.5%

[0080] The carbon powder was added to the water and then the Polycarboxylate thickener was slowly dispersed into the agent while mixing. The result was a black low viscous gel similar to the one in example 1. The reactant was added into an emulsion type explosive such as in example 1 which gassed and increased volume by approximately 10% after 20 minutes in 15 degrees Celsius. The emulsion detonated at 4300 meters/second in a 42 mm plastic hose.

TABLE-US-00003 Example 3 Ratio Substance Function (Weight %) Iron oxide (rust ~45 microns) Catalyst 0.3% Wheat starch Thickener 6% Rapeseed oil Coating agent 93.7%

[0081] The wheat flour was added into the rapeseed oil during heating. Once all clumps had been dispersed, the iron oxide was added and the reactant was cooled. This resulted in a medium viscosity liquid. The agent was added at 2% by weight and a high shear mixer was used to incorporate the agent into an emulsion type HP explosive such as described in example 1. The emulsion increased in volume by approximately 12% and detonated unconfined in a 50 mm plastic tube using a 25-gram PETN booster.

TABLE-US-00004 Example 4 Ratio Substance Function (Weight %) Sodium bicarbonate Catalyst 0.5% PIBSA Emulsifier 1.1% SMO Surfactant/Emulsifier 0.4% Rapeseed oil Coating carrier 20% Water Carrier 78%

[0082] [This is an example of disloving] The Sodium bicarbonate was dissolved in the water creating a water phase. PIBSA, SMO and Rapeseed oil was combined into an oil phase. The water phase was added discontinuously into the oil phase creating a low viscosity gassing emulsion. The gassing emulsion was added into emulsion type HP explosive as described in example 1. The emulsion increased in volume by approximately 10% after 6 hours and detonated unconfined in a 50 mm plastic tube using a 25 gram PETN booster.