BG103545A - Method and installation for the preparation of porous granulated ammonium nitrate - Google Patents

Abstract

The invention relates to a method for the production of porous granulated ammonium nitrate which is a raw material for making explosive and propulsion substances, such as naphtha-ammonium nitrate industrial explosives, as well as to a plant for its materialization. By the method, calcium and/or magnesium nitrate is added to an aqueous solution of ammonium nitrate with a concentration of 85-88 %, the mixture solution produced in being concentrated to 99.7-99.8 %, and a surfactant is added to it, selected from the group of anion sulphonate high-molecular surfactant. The mixture is homogenized and is fed for prill-granulation, compressed air being fed as a counter-flow to the falling granules, maintaining a pseudo-fluidized bed of the porous granules formed. The granule temperature in the upper part of the fluidized bed is maintained within 90 to 120 degree C, and from 35 to 50 degrees C in its downstream part, before its discharge; finally the cooled granules are covered by anti-sticking agent. The plant consists of an evaporator (1), connected across a buffer-collector (2) to the lower part of a high-speed aperture piezometric flow meter-mixer (3), to the top of which a tank (4) is connected across a valve adjuster. The mixer (3) is connected, on the other side, with a low-revolution acoustic granulator (5), mounted at a height not lower than 25 m from the level of the fluidized bed (6) formed in a granulation tower. To the lower part of the tower, a vertical tray mixer (7) by means of a conveyor, is connected, to which a tank (9) is connected. The granules produced have high mechanical strength and are physically stable, regardless of the storage temperature conditions and operation, having, at the same time, high porosity and fully meet with the user needs for their sorption and retention capacity. 5 claims, 1 figure