Patent ID: 6676910
Filing Date: 2004-01-13
Classification: C01F

Abstract:
An improved process for the causticisation of Bayer liquors in an alumina refinery, the process including the steps of:(i) reacting lime with aluminate ions in a Bayer liquor under controlled conditions of low to moderate temperature to form a hydrocalumite species and hydroxyl ions; and, (ii) heating said hydrocalumite species in contact with a Bayer liquor under controlled conditions so as to cause the hydrocalumite species to react with the liquor to form calcium carbonate, aluminate ions and hydroxyl ions, and to obtain a causticised Bayer liquor; wherein the Bayer liquor of step (ii) includes the Bayer liquor of step (i) or is a different liquor than the Bayer liquor of step (i).