E.i. Dupont De Nemours and Company

Du Pont of Canada Limited

James H Owen, Ii

Gordon R Honeyman

The pneumatic loading of essentially free-flowing slurry-bearing ammonium nitrate (AN) prills, i.e., AN prills which carry or support a water gel or water-in-oil emulsion, produces a high-density explosive consisting of the tightly packed whole and crushed slurry-bearing prills. The density of this explosive can be as much as 20% higher than the poured density of the mass of slurry-bearing prills.

Method of producing high-density slurry/prill explosives in boreholes

Explosives that are sensitized blends of inorganic nitrate, e.g., AN, particles, such as AN or ANFO prills, and an aqueous slurry comprising a thickened aqueous solution of an inorganic oxidizing salt, preferably AN, are rendered storage-stable by keeping the slurry's water content low enough, and its viscosity high enough, that the slurry is water-retentive. Water immobilization in the slurry, a requirement for storage stability, is achieved despite the slurry's flowable consistency at the time of blending. A blend containing about 25% slurry or less, is essentially in the form of a granular mass of free-flowing, high-density, slurry-bearing prills, and the slurry is sensitizable by the prills alone. As the slurry content exceeds about 25%, the blend takes on the characteristics of a thick slurry, requiring a supplemental sensitizer in the slurry per se. Slurries containing a nitrogen-base salt of an inorganic oxidizing acid, preferably monomethylamine nitrate, are preferred because this additive affords a saturated solution with lower water content, and also can act as a sensitizer.

Stable nitrate/slurry explosives

Emulsion-type explosives having improved storage stability are formed by combining an aqueous solution of an inorganic oxidizing salt and an oil in the liquid phase with agitation in the presence of a fatty acid, e.g., oleic or stearic acid, and an ammonium or alkali metal hydroxide, and incorporating dispersed gas bubbles or voids in the resulting water-in-oil emulsion. An emulsifying system including a fatty acid salt is formed in situ. The product contains the fatty acid salt, fatty acid, and hydroxide in a stabilizing equilibrium which permits the product to retain its explosive properties after storage at temperatures as high as 49.degree. C. or more.

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Jefferson City, MO, United States of America

James H Owen, Ii