Electrolysis of solid metal sulfide to metal and sulfur in molten NaCl-KCl

Electrochemical desulfidation of solid sulfide has been studied for the first time in the mixed NaCl-KCl melt. At 700 degrees C, the equimolar NaCl-KCl enabled highly efficient transport of the S2- ion and high speed electro-reduction of porous WS2 pellets to W nanonodules (50-100 nm). The graphite anode was experimentally confirmed to be an ideal non-consumable anode, on which the S2- ion was oxidised to gaseous sulfur. The current efficiency of the electrolysis of WS2 was higher than 90% and the energy consumption could be lower than 1.23 kWh/kg-W. These findings promise new green methods for the preparation of various transition metals and alloys by electro-desufidation of their solid sulfides. (C) 2011 Elsevier B.V. All rights reserved.