METHOD OF SUB-SLUDGE WATER TREATMENT Russian patent published in 2024 - IPC C01F7/02 C01F7/66 C01F7/142 C02F9/00 

FIELD: chemical or physical processes.

SUBSTANCE: invention relates to chemical technology, in particular to a method of producing amorphous aluminum hydroxide and aluminum hydroxide with a pseudoboehmite structure, and can also be used to produce granular active aluminum oxide, catalysts, supports and in other industries. Processing of sub-sludge water of alumina production includes filtration of sub-sludge water, its carbonisation by means of saturation with carbon dioxide, separation of formed sediments, their washing with water and drying. At the same time carbonisation of sub-sludge water is carried out in two stages. First stage of carbonisation is carried out to pH value of pulp, at which a precipitate in the form of amorphous aluminum hydroxide precipitates from the solution, the obtained pulp is filtered to obtain a precipitate, which is washed to obtain a product in form of amorphous aluminum hydroxide and a carbonate solution. Obtained carbonate solution is directed to second stage of carbonisation to pH value of pulp, at which the maximum amount of the target precipitate is deposited, the obtained pulp is filtered, the precipitate is washed to obtain a product in the form of pseudoboehmite.

EFFECT: obtaining aluminum hydroxide powders of pseudoboehmite structure with low content of impurities.

6 cl, 2 dwg, 3 tbl, 7 ex