Abstract

The objective of this study was to explore the sintering and leaching provision of Bayer’s process waste residue (Red Mud). The chemical composition of red mud was ~16.07% Al₂O₃, ~53.75% Fe₂O₃, ~4.24% TiO₂, ~8.25% SiO₂, ~3.82% Na₂O, ~0.148% V₂O₅, ~0.02% MgO, ~0.157% MnO, ~0.085% Ga₂O₃, ~0.007% ZnO, 0.099% K₂O, ~11.83% LOI (loss on ignition) and rare earth elements in ppm label. The effect of Na₂CO₃ additive, MgO and Na₂CO₃ additives, sintering temperature, sintering time and leaching time on the efficiency of alumina extraction from red mud was investigated. Studies show that it was possible to extract alumina from red mud with highest extraction efficiency of 98.70%. The formation of Na₂MgSiO₄, Mg₂SiO₄, MgTiO₃ and Mg₂Fe₂O₅ phases during sintering of red mud with MgO and Na₂CO₃, enhance alumina extraction efficiency. X-ray diffractometer and Scanning Electron Microscope studied the formation of Na₂MgSiO₄, Mg₂SiO₄, MgTiO₃ and Mg₂Fe₂O₅ phases.

Keywords

Red Mud, Sintering, Leaching, Alumina and Extraction