Molten salts play multiple important roles in the electrolysis of solid metal compounds, particularly oxides and sulfides, for the extraction 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 dissolving 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 unwanted 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 molten salts and cathodes at different reduction states, including perovskitization, non-wetting of molten salts on pure metals, carbon contamination of products, formation of oxychlorides and calcium intermetallic compounds, and oxygen transfer from the air to the cathode product mediated by oxide anions in the molten salt.

熔融盐在固体金属化合物（尤其是氧化物和硫化物）的电解过程中扮演着多个重要角色，用于提取金属或合金。这些作用中的某些作用在帮助金属提取方面是积极的，例如溶解氧化物或硫化物阴离子，并将其运输到阳极以进行放电，并提供高温以降低动力学屏障以破坏金属氧或金属氧。硫键。然而，熔融盐也具有不利的影响，包括电子导电性和显着的溶解氧气和二氧化碳气体的能力。另外，尽管与水电解质相比，熔融盐在成分，物理性质和惰性电极处的分解反应方面相对简单，熔融盐的高温可能会促进不需要的电极-电解质相互作用。本文简要而有选择性地回顾了Fray-Farthing-Chen（FFC）剑桥工艺在过去二十年中的研究和开发，重点是观察，理解和解决熔融盐与阴极在不同还原状态下的各种相互作用的解决方案，包括钙钛矿化，熔融盐在纯金属上的不润湿，产品的碳污染，氯氧化物和金属间化合物钙的形成，以及由熔融盐中的氧化物阴离子介导的氧气从空气转移到阴极产品。