METHOD FOR PRODUCTION OF ALUMINA FROM NEPHELINE MATERIALS Russian patent published in 1995 - IPC

FIELD: production of alumina. SUBSTANCE: method for production of alumina from nepheline materials includes preparation of nepheline-limestone charge, its sintering and leaching of sinter. Obtained aluminate solution is separated into two parts. One part of aluminate solution is subjected to desilication in open mixers in the presence of nepheline-limestone charge, and the other part of aluminate solution is desilicated in two stages. The first stage includes desilication in autoclaves with addition of nepheline-limestone slime, separation of produced precipitant from solution and direction of precipitant for sintering. The second stage includes desilication of solution produced in the first stage in open mixers with addition of lime and separation of hydrogarnet slime into precipitant. Hydrogarnet slime may be directed to the first stage of desilication. Supplied to autoclaves is nepheline-limestone slime. EFFECT: higher efficiency. 3 cl