ALUMINA OBTAINING METHOD Russian patent published in 2015 - IPC C01F7/22 C01F7/30 

FIELD: metallurgy.

SUBSTANCE: invention can be used in metallurgy, for processing of aluminium-bearing raw materials. The alumina obtaining method includes processing of aluminium-bearing raw materials with hydrochloric acid, extraction from clarified chloride solution of aluminium chloride hexahydrate crystals and their two-phase thermal decomposition with alumina obtaining. The second stage of thermal decomposition is performed at the temperature 150-450°C and continuous water vapour supply at the ratio of total mass of supplied steam to the mass of the obtained alumina equal to 0.2-5.7.

EFFECT: invention allows to improve alumina quality, namely to lower the content of residual chlorine down to 0,01% and the content of alpha phase down to 10%, to lower energy consumption 1,5-2 times at high process efficiency.

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