METHOD FOR PROCESSING FLUORIDE AND SILICON CONTAINING WASTE OF ALUMINUM MANUFACTURE Russian patent published in 2018 - IPC C01F7/54 C22B7/00 

FIELD: metallurgy.

SUBSTANCE: invention relates to non-ferrous metallurgy, in particular, to the processing of spent lining of electrolyzers to produce aluminum in order to extract fluorine compounds, return them to main production and other uses. Method includes grinding, leaching, separation of the liquid and solid pulp phases, treatment of the solution with the release of a fluorine-containing product. In the method, waste from the overhaul of the insulating part of the aluminum electrolysis cell containing fluorine, aluminum, sodium and silicon is treated. Leaching is carried out with a salt solution containing sodium carbonate in an amount of not more than 5.0 g/dm³, at a molar ratio of sodium fluoride to sodium bicarbonate at a level of 1.4–1.5÷1 with the subsequent phase separation and precipitation from a solution of cryolite with a silicon oxide content of not more than 0.9 wt.%.

EFFECT: cryolite with reduced silicon content that meets the requirements of the aluminum industry is obtained.

1 cl, 2 tbl, 1 ex