Electrochemically Converting Liquid Cu2S‐Sb2S3 to Liquid Cu2Sb and Sulfur in Molten Salt at 730 °C

Abstract

AbstractConventional sulfide metallurgy suffers from SOx gas emission and high energy consumption, owing to the multiple‐step extraction processes and high temperatures that are above the melting point of the extracted metals. Herein, liquid Cu2Sb alloy can be directly electrochemically extracted from the liquid Sb2S3‐Cu2S with no sulfide oxides emission in eutectic NaCl‐KCl molten electrolyte at 730 °C. The use of Sb2S3 decreases the melting point of Cu2S and the Sb decreases the melting temperature of Cu. The Sb2S3‐Cu2S mixture experiences three stages in the electrochemical desulfurization process: the insertion of Na+ into liquid sulfides, the removal of S2− and metallization, and finally the formation of uniform liquid Cu2Sb alloy. The Sb2S3‐Cu2S can be completely electro‐converted into Cu2Sb at 2.6 V for 6 hours. This study provides a straightforward and environmentally friendly route to electro‐synthesize liquid alloys from their molten sulfide minerals.