METHOD FOR COMPLEX PROCESSING OF RED SLUDGE BY HEAP LEACHING Russian patent published in 2021 - IPC C22B3/16 C22B59/00 C01F17/00 C01F7/00 C22B21/00 C01G49/00 C22B7/00 C22B26/20 

FIELD: non-ferrous metallurgy.

SUBSTANCE: invention relates to the technology of extraction and concentration of rare metals, light, alkaline earth and rare earth metals from red sludge, waste of alumina production. The complex processing of red sludge includes heap leaching, filtration and separation of the extracted target products. The pulp of the red sludge is filtered, the filtered product is mixed with formic acid, then dried at a temperature of 50 to 150°С. Heap leaching of the resulting cake with water is carried out to obtain the 1st production solution containing Al, Na, Ca, Sc and REE, the 2nd production solution containing Ca and Al, and the waste red sludge containing a desalinated ferrous concentrate. The 1st solution is neutralized with lime milk to obtain a concentrate of Al, Sc and REE, and a solution of Na, Ca formates, from which concentrated solutions of sodium formate and crystalline calcium formate are obtained. A scandium/rare earth concentrate and an aluminate solution are obtained from the concentrate. From the 2nd production solution, an aluminum concentrate and a filtrate (a solution of calcium formate) are obtained, which is sent to the evaporation to obtain a crystalline calcium formate and a concentrated solution of calcium formate. Aluminum concentrate is used to produce a scandium/rare earth concentrate and an aluminate solution.

EFFECT: method provides complex processing of red sludge to obtain a scandium/rare earth concentrate, aluminum in the form of an aluminate solution, a concentrated solution of sodium formate, crystalline sodium formate and a dealkalized ferruginous concentrate.

1 cl, 4 dwg, 6 tbl, 3 ex