A review on the extraction and recovery of critical metals using molten salt electrolysis

Recently, the demand for critical metals in strategic emerging industries has exploded. The development of clean, efficient, and simple extraction methods for critical metals, as well as new technologies for the high-value utilization of critical metals in secondary resources will help to achieve a sustainable supply of critical metals and promote the rapid development of strategic emerging industries. High temperature molten salt electrolysis is an economical and green metal extraction method that plays a vital role in energy supply and resource extraction. Therefore, this article aims to review the application of high temperature molten salt electrolysis technology in the extraction and recovery of critical metals. First, the application status of high temperature molten salt electrolysis technology in aluminum and titanium industries was taken as an example, and the technical methods and technical difficulties in the extraction of critical metals from raw ore resources are introduced and analyzed. After that, the high temperature molten salt electrolysis technology was introduced into the field of secondary resources recovery, and the application of molten salt electrolysis technology in secondary resources, such as spent lithium-ion batteries, abandoned rare earth metal materials, spent fuel, and waste cemented carbide scrap, was systematically summarized. Several different high temperature molten salt technologies are discussed to explore the promising route in terms of environmental protection, technological innovation, and economic feasibility. Finally, the possible problems in the industrial application of high temperature molten salt electrolysis technology are summarized, and the future development direction of molten salt electrolysis technology is proposed.