METHOD OF REMOVING IMPURITIES FROM ALUMINATE SOLUTIONS Russian patent published in 2012 - IPC C01F7/47 

FIELD: chemistry.

SUBSTANCE: invention relates to nonferrous metallurgy and specifically to the technology of removing impurities from aluminate solutions when producing alumina from aluminium-containing material, including bauxites. Impurities are removed from aluminate solutions by adding said solutions to sodium sulphide pulp which is diluted after bauxide leaching to concentration 0.20-0.34 g/dm³. The obtained pulp is treated with air in amount of 0.2-0.3 nm³/m³ diluted pulp in steady conditions. The pulp is held in a purifier in continuous flow while stirring. The pulp is then taken for thickening and subsequent separation of sludge. The obtained thickener discharge is taken for post-filtration. The ratio of the volume of diluted pulp in the purifier to that of the pulp flowing through the purifier is equal to 2.7:1.

EFFECT: achieving purification not only from zinc oxide, but also from organic substances - humic acids and silicon oxide.

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