Recovery of Rare Earths from Rare-Earth Melt Electrolysis Slag by Mineral Phase Reconstruction

Most rare-earth metals and alloys in the world are produced through molten salt electrolysis, resulting in the creation of a substantial amount of rare-earth melt electrolysis slag (RMES) that contains high levels of rare-earth elements (REEs) and holds significant recycling value. The key to efficiently recycling REEs from RMES lies in the conversion of rare-earth fluoride (REF3) into compounds that are more soluble in water or acid. This article summarizes various processes that researchers have utilized in recent years to recover REEs from RMES, categorizing them into three methods (alkali mineral phase reconstruction, salt mineral phase reconstruction, and acid mineral phase reconstruction) based on the reconstruction of REF3 phases. A comparison is made between the characteristics, advantages, and disadvantages of each extraction process, offering valuable insights and technical support for the development of efficient recovery methods for rare earths and other valuable metals to combat the scarcity of rare-earth resources.