METHOD OF PRODUCING ALUMINIUM OXIDE FROM MEDIUM- AND LOW-GRADE BAUXITE Russian patent published in 2013 - IPC C01F7/06 

FIELD: chemistry.

SUBSTANCE: invention relates to metallurgy. A recycled mother solution and a dealuminated residue which contains tricalcium hydroaluminate and silica are added to bauxite to conduct a Bayer leaching process. As a result of the Bayer leaching process, a suspension is obtained, which is divided to obtain sodium aluminate solution and red Bayer mud. The sodium aluminate solution is further processed to obtain a mother solution and aluminium oxide. Lime and recycled mother solution are added to the red Bayer mud to conduct wet processing of the red Bayer mud. The obtained suspension is divided to obtain a solution and recycled red mud. The recycled red mud is washed. Lime is added to a portion of the solution obtained after processing the red mud to obtain a dealuminated suspension, which is divided to obtain a dealuminated residue which contains tricalcium hydroaluminate and silica, and a recycled alkaline solution. The dealuminated residue is fed to the leaching step, while the recycled alkaline solution is fed to the red mud wet processing step.

EFFECT: invention increases efficiency of the method.

13 cl, 3 dwg, 18 ex