Fused salt electrolytic reduction of solid oxides and oxide mixtures for green production of metals and alloys

Abstract

In this work, a fused salt electrochemical process was investigated experimentally for production of metals and alloys directly from respective solid oxides by electro-deoxidation. Direct electrochemical reduction of the oxides was carried out in molten CaCl₂-based chlorides in an electrolytic cell, incorporating an oxygen-evolving inert anode, over the temperature range of 850–950°C. The technical viability of the process was demonstrated by the electro-deoxidation of pure oxides and oxide mixtures including NiO, Nb₂O₅, Nb₂O₅/TiO₂ and Nb₂O₅/SnO₂ to produce nickel metal, niobium metal, NbTi alloys and the intermetallic compound, Nb₃Sn. Compared with the conventional metallurgical processes for producing these metals and alloys, this new electrochemical process appears to be much less energy intensive, with lower costs and no direct greenhouse gas emissions from the electrolytic reduction process. The present electrolytic reduction process has the potential to be scaled up for the green extraction of a number of non-ferrous base metals and processing of many advanced alloys.

Keywords

ELECTRO-DEOXIDATION FUSED SALTS ENVIROMENT SOLID ELECTROLYTES

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