China Nonferrous Metallurgy

Rare earth metals and their alloys have become essential strategic resources in today's society, and they are mainly prepared by molten salt electrolysis. This paper introduces the research progress on the electrolytic preparation of rare earth metals and their alloys by high-temperature molten salt and room-temperature molten salt (ionic liquids) systems. Regarding the high-temperature molten salt system, it introduces the electrolytic preparation of rare-earth metals by chloride molten salt and fluoride molten salt systems, the electrolytic preparation of rare-earth alloys by different cathodes (inert cathode, active solid cathode, active liquid cathode), and the research progress of China's rare-earth molten salt electrolysis on electrolytic cell, automation and intelligent technology. Regarding the ionic liquids system, the research progress on the electrolytic preparation of rare-earth metals and their alloys by several types of ionic liquids, such as halogen metalate type, air and water stabilized type, task-specific type, and deep eutectic solvent, is introduced. In the high-temperature molten salt system has been realized in a variety of rare earth metals and their alloys of industrial production, but with the “carbon peaking and carbon neutrality goals” strategy continues to promote, rare earth electrolysis, high energy consumption, high emissions of the problem is imminent, the development of energy-saving, environmentally friendly rare earth electrolysis of the new process and equipment is the direction of the future development of rare earth electrolysis. Ionic liquids system electrolysis products are mostly particles or thin films, the preparation of bulk metal is still difficult, continue to develop low-cost ionic liquids with low viscosity, high salt solubility, high stability and other excellent physicochemical properties, for the preparation of low-temperature electrolysis of rare earth metals and their alloys is of great significance.