GB1318116A - Explosives and the preparation and use thereof - Google Patents

Abstract

1318116 Explosive compositions NISSO KENZAI KOGYO CO Ltd 6 Aug 1970 [2 May 1970] 37919/70 Heading C1D An explosive composition comprises a solidified mixture of 20-80% by weight of an explosive ingredient and 80-20% by weight of cement or calcined plaster. The composition has a "force value" below 9000 and preferably below 4000 litre-kgms./cm.<SP>2</SP>, a detonation velocity D of 4000-8500 m./sec., a specific gravity p greater than 1À3 and a value of pD<SP>2</SP> in the range 30-130 (kgms./sec.)<SP>2</SP>. The explosive ingredient may be powdered RDX, PETN, TNT, HMX, picric acid, or tetryl; this powder is mixed in the presence of water with alumina cement, magnesia cement, Portland cement, or plaster (calcined gypsum). Alternatively, the explosive powder may be mixed with litharge cement which comprises PbO and glycerine. To increase the specific gravity, powdered iron, iron oxide, Al 2 O 3 , MnO, TiO 2 , ferrosilicon, or stone may be added. The composition may be placed in a borehole in a block of concrete, mortar, or granite and surrounded in the hole by a highly compressible material having a "shock impedance" greater than 1400 m./sec., for example water, cement or gypsum slurry, or solutions of zinc, calcium, or sodium chloride, or sodium perchlorate. On explosion there is little scattering of pieces of material and the sound of the explosion is reduced. The explosive may be built into a structure reinforced by steel wool or wire nets, which structure has later to be demolished.