Patent ID: 7244404
Filing Date: 2007-07-17
Classification: C01F

Abstract:
1. A process for the removal and causticisation of sodium oxalate and/or sodium sulphate from a Bayer process liquor containing carbonate ions and oxalate and/or sulphate ions, the process comprising the steps of: (a) treating the Bayer process liquor to remove carbonate ions by forming carbonate-bearing solids; (b) separating the carbonate-bearing solids to form a clarified liquor containing residual carbonate ions and oxalate and/or sulphate ions; (c) adding lime to the clarified liquor to remove the residual carbonate ions and form reacted lime solids including the oxalate and/or sulphate ions; and, (d) separating the reacted lime solids to form a purified liquor.