Electrolysis of a molten semiconductor

This study addresses the limitations of traditional electrolysis methods for extracting metals from transition-metal sulfides due to their semiconductor nature. The objective was to develop a high-throughput electro-desulfurization process to convert molten stibnite (Sb2S3) into pure liquid antimony and sulfur vapor. The methodology involved introducing a distinct secondary electrolyte that prevents electronic shorting across the electrolysis cell. By using a carbon anode immersed in this secondary electrolyte, liquid antimony is collected beneath the molten stibnite while sulfur is released at the top. Results indicate that this direct sulfide electrolysis not only achieves a purity of 99.9% for liquid antimony but also circumvents harmful emissions like CO2, CO, and SO2, significantly reduces energy consumption, and enhances productivity—all in a single operational step. This innovative approach lowers both capital and operational costs while being broadly applicable to various electronically conductive transition-metal chalcogenides.