Patent ID: 9631255
Date: 2017-04-25
CPC Classifications: C01F,C01P,C22B,Y02P

Claim:
1. A method of alumina recovery from an aluminum containing raw material comprising the following steps: (i) leaching the aluminum containing raw material with hydrochloric acid to form a supernatant solution of aluminum chloride hexahydrate; (ii) removing any solids from the supernatant solution of step (i); (iii) extracting aluminum chloride hexahydrate crystals from the supernatant solution; (iv) heating the aluminum chloride hexahydrate crystals from step (iii) to between 110 and 250° C. in a first heating stage until aluminum oxychlorides form and there is a depletion of water released during the first heating stage; and (v) treating the product of step (iv) to between 150 and 450° C. and delivering water vapour to the product of step (iv) at a ratio of a total weight of the water vapour to a weight of recovered alumina from 0.2-5.7 to recover alumina from the aluminum containing raw material.