Abstract

A method for the preparation of alumina from alunite, the method comprising the steps of: (i) attrition of an alunite material; (ii) washing and settling the alunite material to reduce sodium content; (iii) acid leaching and roasting the Na-reduced alunite material; (iv) passing the product of the acid leach and roast step (iii) to a water leaching step to produce a liquid product comprising aluminium and potassium; (v) subjecting the liquid product of step (iv) to a precipitation step to precipitate an aluminium salt; (vi) purifying the aluminium salt; and (vii) subjecting the purified aluminium salt to a calcination step to produce alumina.

IPC Classes  ?

• C01F 7/306 - Thermal decomposition of hydrated chlorides, e.g. of aluminium trichloride hexahydrate
• B01D 9/02 - Crystallisation from solutions
• C01F 7/56 - Chlorides
• C01F 7/745 - Preparation from alums, e.g. alunite
• C22B 1/02 - Roasting processes
• C22B 3/04 - Extraction of metal compounds from ores or concentrates by wet processes by leaching
• C22B 3/06 - Extraction of metal compounds from ores or concentrates by wet processes by leaching in inorganic acid solutions
• C22B 21/00 - Obtaining aluminium