A PROCESS FOR RECOVERING LUMINA

摘要

A process for recovering alumina values from a first alkaline liquor having an initial concentration of aluminate ions and hydroxyl ions in solution is described. The first alkaline liquor is treated with a hydroxide of a metal other than aluminium to form an aluminium-bearing layered double hydroxide and produce a treated stream of first alkaline liquor, the treated stream of first alkaline liquor having a final concentration of aluminate ions less than the initial concentration of aluminate ions. The aluminium-bearing layered double hydroxide is separated from the treated stream of first alkaline liquor. Thereafter the clarified treated stream of first alkaline liquor is returned to a first location within an alumina refinery. The separated aluminium-bearing layered double hydroxide is contacted with a solution containing carbonate ions to form a slurry comprising an insoluble salt of the metal other than aluminium and a second liquor comprising aluminate ions released from the aluminium-bearing layered double hydroxide.