The DSP concentrate sinter-leach process for aluminium and sodium recovery 1

Abstract

ABSTRACT The combination Bayer sinter-leach process has been shown to be a technically viable method for reprocessing bauxite residue to recover lost caustic and alumina. However, this method suffers from high energy requirements and reagent consumption associated with processing the large volume of bauxite residue, the majority of which is gangue. To address this issue, processing a desilication product (DSP) concentrate derived from the novel Sandy Desilication Product process is studied. In the present study, critical processing parameters surrounding the sintering stage were investigated including the grade and particle size of the DSP concentrate, the limestone addition rate, using calcium oxalate as an alternative to limestone and reductive sintering. The DSP concentrate sinter mineral phases were specified using quantitative XRD and the sinter products were assessed for leachability. Maximising the silicate reaction extent during sintering was found to be important to ensure high leachability.