NEPHELINE RAW MATERIAL-BASED ALUMINA PRODUCTION PROCESS Russian patent published in 2004 - IPC

FIELD: nonferrous metallurgy.

SUBSTANCE: process comprises three-step preparation of batch from alumina-containing material, soda solution, and limestone, and caking the batch in rotary oven followed by cooling. In the first step, electrolytic aluminum production waste in the form of slime in amount 1-5% based on the dry weight of batch and soda solution with concentration 40-60 g/L are added to alumina-containing material. Resulting mix is ground on first wet-grinding mill. In the second step, soda solution (40-60 g/L) is added to limestone and resulting mix is ground on second wet-grinding mill. Finally, soda-slime-nepheline and soda-limestone pulps are after-ground on third wet-grinding mill, after which soda solution (40-60 g/L) is added to obtain batch with 23-27% moisture content.

EFFECT: increased degree of alumina and alkali recovery, reduced power consumption, and weakened environmental pollution impact.

3 tbl, 5 ex