Method of producing alumina and potassium sulphate from alunite

A method for processing alunite consisting in that alunite ore is treated with a solution of caustic alkalis at a maximum temperature of 60 DEG C, and a solid residue resulting from the above operation and containing largely potassium and sodium sulphates, is washed with hot water. As a result, potassium and sodium sulphates are dissolved in the wash water, and potassium sulphate is isolated by the action of a caustic-potash solution. The method enables losses of alkalis and aluminium during processing alunite ores containing active forms of silicon compounds to be much reduced, which compound when treating alunite ores with a solution of caustic alkalis, are liable to form insoluble aluminosilicates which are discarded into slime and thus lost together therewith when the latter is separated from the process solution.