Blasting slurry compositions containing calcium nitrate and method of preparation

Abstract

Slurry blasting compositions of low water content and high density, including substantial proportions of calcium nitrate as an oxidizer component, can be sensitized in various ways to produce economical explosive compositions. Sensitizers may include aluminum powder, granular explosives such as smokeless powder, TNT, etc.; a particularly preferred sensitizer or fuel is ethylene glycol. Solid carbonaceous fuels and conventional thickeners may be added. The calcium nitrate may be produced directly from burned lime with nitric acid and/or other nitrates.

What is claimed is: 
     
       1. A pumpable and pourable aqueous slurry blasting composition of low water content and high sensitivity, comprising a liquid phase which includes a solution of powerful oxidizer salts selected from the group which consists of inorganic nitrates, chlorates and perchlorates and including at least 10% by weight, based on the total composition, of calcium nitrate, said liquid comprising water and ethylene glycol and including a viscosity-increasing agent in the liquid phase per se to impart thereto a viscosity sufficient to entrap and hold tiny bubbles of gas dispersed in said phase, a sufficient quantity of gas in the form of tiny bubbles being dispersed throughout said liquid phase to substantially enhance the sensitivity of the whole composition to detonation, and a storage stable, strongly cross-linked thickener or gel former selected from the group which consists of polysaccharide gums and starches in proportions sufficient to permanently hold said gas bubbles dispersed in situ and also to inhibit segregation of solid particles suspended in the liquid phase and inhibit intrusion of borehole water into said composition. 
     
     
       2. Composition according to claim 1 which contains at least 8% of ethylene glycol and wherein the thickener is cross-linked by a combination oxidation-reduction cross-linking system. 
     
     
       3. Composition according to claim 1 wherein the slurry contains sufficient gassing agent to hold its density below 1.2 grams per cubic centimeter under a pressure of 50 psi. 
     
     
       4. Composition according to claim 1 in which there is at least 20% by weight, based on total composition, of calcium nitrate. 
     
     
       5. Composition according to claim 1 which includes at least 8% of ethylene glycol. 
     
     
       6. Composition according to claim 1 which includes at least 10% of calcium nitrate, at least 8% of ethylene glycol, and not more than 8% of water, not including water of crystallization associated with said calcium nitrate. 
     
     
       7. Composition according to claim 1 which includes at least 5% of ethylene glycol, at least 10% of calcium nitrate, an oxidation-reduction cross-linked gel former, and sufficient gassing agent to keep the slurry density below 1.2 g/cc. under a pressure of 50 psi. 
     
     
       8. Composition according to claim 7 which includes finely divided aluminum as a fuel. 
     
     
       9. Composition according to claim 7 which includes at least 8% of ethylene glycol, at least 20% of calcium nitrate, and which is sensitive to detonation in a 2-inch column at 10° C by a standard booster. .Iadd. 10. A pumpable and pourable aqueous slurry blasting composition of low water content and high sensitivity, comprising a liquid phase which includes a solution of powerful oxidizer salts selected from the group which consists of inorganic nitrates, chlorates and perchlorates and including at least 10% by weight, based on the total composition, of calcium nitrate, said liquid comprising water and propylene glycol, and including a viscosity -increasing agent in the liquid phase per se to impart thereto a viscosity sufficient to entrap and hold tiny bubbles of gas dispersed in said phase, a sufficient quantity of gas in the form of tiny bubbles being dispersed throughout said liquid phase to substantially enhance the sensitivity of the whole composition to detonation, and a storage stable, strongly cross-linked thickener or gel former selected from the group which consists of polysaccharide gums and starches in proportions sufficient to permanently hold said gas bubbles dispersed in situ and also to inhibit segregation of solid particles suspended in the liquid phase and inhibit intrusion of borehole water into said composition. .Iaddend.