FIELD: chemistry.
SUBSTANCE: invention relates to nonferrous metallurgy, particularly to the technology of producing alumina from alumina-containing material. Alumina-containing material is leached. The obtained aluminate solution is separated from red mud and the aluminate solution is taken to the crystallisation step which is carried out at temperature 25-39°C by adding crystalline aluminium sulphate to the aluminate solution in amount of 3.75-6.00% of the content of aluminium oxide in the aluminate solution. A mother solution and a residue containing aluminium hydroxide is obtained. The aluminium hydroxide residue is taken for calcination to obtain alumina.
EFFECT: invention increases efficiency of the process by increasing the degree of decomposition of the aluminate solution and cutting duration of decomposition of the solution.