METHOD OF PROCESSING BAUXITES INTO ALUMINA Russian patent published in 2013 - IPC C01F7/06 C01F7/14 

FIELD: chemistry.

SUBSTANCE: invention relates to method of processing bauxites into alumina. Method includes grinding bauxite in spent liquor, leaching, thickening with obtaining aluminate solution and red sludge, washing red sludge, decomposition of aluminate solution with obtaining aluminium hydroxide and mother liquor, evaporation of mother liquor with obtaining spent liquor and calcinations of aluminium hydroxide with obtaining alumina. After grinding bauxite in spent liquor obtained pulp is heated until water is removed from spent liquor and dry residue is obtained, evaporated water is condensed, combined with dry residue and directed to leaching, and after operation of thickening aluminate solution is subjected to operation of desiliconisation with obtaining white sludge and aluminate solution, which is directed to decomposition operation.

EFFECT: ensured are increase of chemical output of alumina from 83,8 to 97,1%, reduction of red sludge output from 55,8 to 29,5%, reduction of alumina content in wastes of production in form of red sludge from 14,5 to 4,1%, increase of iron oxide content in red sludge from 46,4 to 75,9%, which makes its application as iron ore raw material promising.