METHOD OF PRODUCTION OF GRANULATES FROM CYANIDE OF ALKALI OR ALKALI-EARTH METALS Russian patent published in 2002 - IPC

FIELD: production of granulates from cyanides of alkali or alkali-earth metals by granulation on fluidized bed. SUBSTANCE: method of production of granulates first of all from NaCN-, KCN- and Ca(CN)₂-granulates consists in spraying granulation in fluidized bed where aqueous solution or aqueous suspension containing cyanide of alkali or alkali-earth metal are dispersed in plant for spraying granulation in fluidized bed into nuclei of cyanide of alkali or alkali-earth metal; water is evaporated by means of flow of drying gas passed through fluidized bed; superheated steam is used as drying gas; inlet temperature of superheated steam ranges from 150 to 500 C and fluidized bed temperature ranges from 110 to 350 C; granulated is withdrawn from plant by known method. Superheated steam is circulated in closed cycle and excessive steam formed during evaporation is removed from cycle; steam escaping from fluidized bed is fed to dust collector after which it is divided into two flows: one flow is admitted to combustion chamber and superheated steam formed at this is returned to process as drying gas and second flow consisting mainly of excessive steam is removed from cycle and is washed-out and/or condensed. EFFECT: improved quality of granulates at minimum emission of waste gases. 6 cl, 1 dwg, 1 ex