Toward optimisation of electrolytic reduction of solid chromium oxide to chromium powder in molten chloride salts

摘要

Electrochemical reduction of solid Cr{sub}2O{sub}3, in the form of an assembled cathode of porous pellets attached to a current collector, to chromium powder was investigated in molten CaCl{sub}2 and a molten equimolar mixture of CaCl{sub}2 and NaCl. The study focused on the influence of pellets preparation conditions, cell voltages and temperatures on the reduction process. Analyses were reported of the characteristics of the current-time plots of the constant voltage electrolysis under different conditions, cyclic voltammograms of solid Cr{sub}2O{sub}3 in the molten equimolar mixture of CaCl{sub}2 and NaCl, the microstructures and elemental compositions of the reduced pellets. Particularly, attention was given to the intermediate product of the electrolysis, calcium chromites of various stoichiometries, aiming to achieve a better understanding and optimisation of the reduction process.