METHOD FOR COMPLEX PROCESSING OF GAS CLEANING SOLUTIONS IN ALUMINUM PRODUCTION Russian patent published in 2023 - IPC C01D5/00 C01F7/54 C01F7/02 

FIELD: chemical technology.

SUBSTANCE: invention can be used for production of commercial products from aluminum production waste. In the method for complex processing of an aluminum production gas purification solution containing NaF, Na₂CO₃, NaHCO₃ and Na₂SO₄, an aqueous solution of Al₂(SO₄)₃ is added and the resulting solution is mixed, to which a flocculant is added, sedimentation and thickening of the solution are carried, the condensed solution is filtered under vacuum and separated into a cake of cryolite and aluminum hydroxide concentrate and a clarified Na₂SO₄ solution. The clarified Na₂SO₄ solution is evaporated and dried to obtain Na₂SO₄ crystals, and the cake of cryolite concentrate and aluminum hydroxide is dried at a temperature of 500-700°C. The cake of cryolite concentrate and aluminum hydroxide is fed into a drum drying oven, in which at a temperature of 500-700°C γ-modification of Al₂O₃ is obtained and crystallization moisture is removed until it takes up 1 wt.%.

EFFECT: it is possible to obtain commercial quality sodium sulfate and cryolite by acting on the gas cleaning solution with aluminum sulfate.

2 cl, 2 ex