An Investigation on Treatment of Bauxite through Hydrogen Plasma

Abstract

Extraction of metals from their oxides is primarily extracted through pyrometallurgy, which uses carbon as major reducing agent. For using carbon have the limitations of future supply and environmental pollution. In order to avoid this problem hydrogen can be used as an alternative source of reducing agent for extraction of metals. From the Ellingham diagram it is also observed that hydrogen (H-H2O & H+-H2O) is placed below almost all metal oxides (M-MxOy). Hence, in different extractive metallurgical processes hydrogen can be used as a standard reducing agent for the reduction of metal oxides. It has unique thermodynamic properties aiding the economic reduction process and its combustion product is water which is environmentally harmless unlike carbon oxides/carbon monoxide. In the present study an attempt has been made to investigate reduction of bauxite through hydrogen plasma and molecular hydrogen. For this purpose some experiments are being carried out for the reduction of Al2O3 present in bauxite by using hydrogen in form of plasma and also by molecular hydrogen. Further, constituents of reduced bauxite sample with hydrogen plasma and molecular hydrogen is separated by acid leaching. Reduced bauxite sample and separated constituent are characterized by X-ray diffraction technique. It is observed that only iron oxide present in the sample was reduced under the processing conditions.