GB476285A - Improvements in or relating to explosives and methods of manufacture thereof - Google Patents

Abstract

476,285. Explosives. HERCULES POWDER CO. May 3, 1937, No. 12614. Convention date, May 11, 1936. [Class 9 (ii)] Crystals of ammonium nitrate are coated with a metal nitrate in order to increase their sensitiveness to detonation. According to a preferred method, a solution of a metal nitrate is added to the ammonium nitrate crystals and the mixture dried. The coating solution may also contain ammonium nitrate and is preferably almost saturated with the metal nitrate. Alternatively, ammonium nitrate crystals are treated while wet with the metal nitrate in dry condition. According to one example, a solution is prepared by dissolving 132 parts by weight of ammonium nitrate and 50 parts by weight of sodium nitrate in 66 parts by weight of water at about 27‹ C., this solution being saturated with respect to ammonium nitrate and almost saturated with sodium nitrate. This solution is then applied at 27‹ C. to 950 parts by weight of dry granular ammonium nitrate of such particle size that over 95 per cent will pass a 40 mesh screen, about 30 per cent will pass a 100 mesh screen and less than 10 per cent will pass a 200 mesh screen. After thorough mixing, the crystals are dried by passing through the mass a current of dry air at about 50 to 60‹ C. with continuous stirring. If desired, the drying may be effected merely by heating the coated crystals and, in this case, the coating solution is preferably heated before applying same to the crystals. The sodium nitrate may be replaced by the nitrate of potassium, copper, lead, zinc, cadmium, nickel, iron, calcium or magnesium. Carbonaceous and/or organic sensitizing ingredients may be dispersed or dissolved in the coating solution. Thus, coal, charcoal, corn meal, flour or wood pulp may be used as the carbonaceous ingredient whilst dinitrotoluene oil, solid dinitrotoluene, trinitrotoluene, dinitronaphthalene and other liquid and solid nitrocompounds may be used as the sensitizing- agent.