A METHOD OF OBTAINING ALUMINA FROM CLAY AND OTHER ALUMINO-SILICATES AND ALUMINA OBTAINED BY THIS METHOD

摘要

A method of obtaining alumina from clay or other alumino-silicate comprises the step of reacting the clay or other aluminium silicate with a salt of an alkali metal or ammonia, the reaction being carried out in the dry state at a temperature between 300-750 DEG C and for a time between 45 and 120 minutes to produce a double salt of aluminium-alkali or aluminium-ammonium. The double salt is then separated from the reaction product by dissolution, and thereafter the aluminium is precipitated as aluminium hydroxide, which is calcined to give crystalline alumina.