GB497832A - Improvements in or relating to the manufacture of explosive compositions or blasting charges - Google Patents

Abstract

497,832. Explosives. TAYLOR, J., WILLIAMS, V. H., and IMPERIAL CHEMICAL INDUSTRIES, Ltd. April 26, 1937, No. 11931. [Class 9 (ii)] A method of producing a low-density blasting- explosive, free from self-explosive sensitizers, consists in incorporating ammonium nitrate and cork meal, with or without additional ingredients other than self-explosive sensitizers, with sufficient water to form a paste and then drying and granulating to yield a product of sufficiently low bulk density to be sensitive to the direct impulse of a commercial detonator. The proportion of cork meal preferably lies between 10 and 15 parts per 100 parts of ammonium nitrate and the compositions produced in accordance with the invention should have a bulk density below about 0À65 gram per cc. Other low-density vegetable cellular carbonaceous ingredients, such as bagasse, megasse or peat may be included and, in addition, a small proportion of relatively dense carbonaceous materials in finely divided form such as starch, dextrine or flour, may be added for example, 4 to 5 parts of starch per 100 parts of ammonium nitrate may be used. Safety or flame-quenching ingredients, preferably of an insoluble nature, such as granular limestone or coarse iron filings, may be included, but these ingredients should not be so finely divided that they occupy the voids between the particles of the other ingredients of the paste. In carrying out the invention, the wet paste is suitably spread out and dried at a raised temperature and the dried cake so produced broken up by light mechanical treatment and sieved through a coarse sieve, e.g. one lying between 6 and 30 mesh, in order to remove unwanted oversize particles. If desired, further quantities of coarse cooling or flame-quenching ingredients may then be admixed. Part or all of the ingredients of the composition may, if desired, be subjected to a preliminary mixing before the incorporation with water. According to the Provisional Specification, compositions may be produced by dry admixture of ammonium nitrate in powdered form with the cork meal.