A system-integrated framework for rare earth element recovery: Source-specific extraction strategies from geological deposits to high-value anthropogenic reservoirs
来源：Science Direct
Rare earth elements (REEs) are essential to high-performance magnets, phosphors, catalysts, batteries, and advanced electronic materials. However, their supply is constrained by geographically concentrated primary deposits, including bastnäsite, monazite, xenotime, and ion-adsorption clays, alongside rapidly increasing industrial demand. This review examines REE distribution across primary geological resources and secondary anthropogenic reservoirs such as NdFeB magnets, tricolor phosphors, petrochemical catalysts, and NiMH hydride alloys. Sector-specific consumption patterns demonstrate significant variability in elemental demand, with permanent magnets representing the highest value application, catalysts dominating light rare earth consumption, and batteries and phosphors contributing structured secondary reservoirs. Extraction challenges are shown to be strongly matrix-dependent, influenced by phase composition, chemical bonding, and microstructural characteristics. Comparative analysis of mechanical, thermal, hydrometallurgical, and solvent-based recovery routes highlights differences in process selectivity, scalability, and technological maturity. The review provides a structured evaluation of resource distribution and recovery pathways to support balanced development of both primary and secondary REE supply strategies.