Interactions of molten salts with cathode products in the FFC Cambridge Process

• 作者: George Z.Chen
• 来源期刊: 矿物冶金与材料学报
• 年，卷（期）: 2020,（12）
• 页码范围: 1572-1587
• 页数: 16页
• 语种: 英文

摘要

Molten salts play multiple important roles in the electrolysis of solid metal compounds, particularly oxides and sulfides, for the ex-traction of metals or alloys. Some of these roles are positive in assisting the extraction of metals, such as dissolving the oxide or sulfide anions, and transporting them to the anode for discharging, and offering the high temperature to lower the kinetic barrier to break the metal-oxygen or metal-sulfur bond. However, molten salts also have unfavorable effects, including electronic conductivity and significant capability of dissolv-ing oxygen and carbon dioxide gases. In addition, although molten salts are relatively simple in terms of composition, physical properties, and decomposition reactions at inert electrodes, in comparison with aqueous electrolytes, the high temperatures of molten salts may promote un-wanted electrode-electrolyte interactions. This article reviews briefly and selectively the research and development of the Fray-Farthing-Chen (FFC) Cambridge Process in the past two decades, focusing on observations, understanding, and solutions of various interactions between mol-ten salts and cathodes at different reduction states, including perovskitization, non-wetting of molten salts on pure metals, carbon contamina-tion of products, formation of oxychlorides and calcium intermetallic compounds, and oxygen transfer from the air to the cathode product me-diated by oxide anions in the molten salt.