IMPROVED BAYER CAUSTICISATION

摘要

An improved process for the causticisation of Bayer liquors in an alumi na refinery, the process including the steps of reacting time with aluminate io ns in a Bayer liquor within a primary reactor under controlled conditions of low to moderate temperature (between 70-80.degree.C) and agitation, to form substantially only a hydrocalumite species and hydroxyl ions; and a secondary reactor wherein said hydrocalumite species formed is subjected to heating 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, whereby a causticised Bayer liquor is obtained and wherein the efficiency of lime utilisation is substantially increased and/or alumina losses are minimised.< /SDOAB>