METHOD FOR PROCESSING OF CALCIUM-CONTAINING WASTE INTO GYPSUM Russian patent published in 1998 - IPC

FIELD: chemical technology; building materials production; production of house-hold chemistry items. SUBSTANCE: method involves preliminary alkalizing of chlorine-containing lime waste till its pH is 11-11.5, followed by its mixing with aqueous solution of sulfate-containing ash (being waste of trotyl production). Then thus obtained gypsum slime is separated by filtration, washed by weak acid to pH 8-8.5 and is dried at 80-100 C. The process is followed by cooperative dehydration with natural raw materials which takes place at 200-250 C, mass ratio of ingredients being 20-40:80-60 respectively. EFFECT: improved efficiency of the method. 2 tbl