ALUMINA PRODUCTION METHOD Russian patent published in 2020 - IPC C01F7/06 

FIELD: metallurgy.

SUBSTANCE: invention relates to non-ferrous metallurgy, in particular to production of alumina from bauxites, and can be used in chemical enrichment of bauxites for use in processing to alumina using Bayer method. Method of producing alumina involves crushing, annealing, dust trapping, hydroclassification, desiliconisation of sands, processing of obtained concentrate according to Bayer method, regeneration of alkaline solution. Regeneration is carried out in two stages, at the first stage - carbonisation of hydraulic classification precipitation together with calcination dust with separation after filtration of silicon and aluminium oxides, which are directed to sintering process, and sodium carbonate solution. At the second step, lime milk is added to the sodium carbonate solution and causticised. After filtration, solid calcium carbonate is separated, which is sent for sintering, and a solution of sodium hydroxide, which is directed to desiliconisation of hydraulic classification sands. After desiliconisation, a silicate-alkaline solution is obtained - a liquid phase which is sent for hydroclassification, and the bauxite concentrate is a solid phase and a finished product. Baking burning bauxite is processed together with bauxite concentrate according to Bayer method.

EFFECT: invention increases silicon module of bauxite concentrate going for Bayer leaching.

1 cl, 3 dwg