Research Progress on the Extraction and Separation of Rare-Earth Elements from Waste Phosphors

Rare earth is an important strategic resource and a key mineral resource for global competition. As the depletion of primary rare-earth resources increases, a great number of rare-earth secondary resources, such as waste phosphor powder collected from fluorescent lamps, cathode-ray tubes, and other luminescent materials, continue to be generated and accumulated. How to achieve the low-carbon extraction and green and efficient utilization of these resources has become an urgent problem to be solved. In recent years, preliminary enrichment methods, such as flotation, magnetic separation, and adsorption, chemical methods, such as acid leaching and alkaline fusion, external-field-enhanced methods (including mechanical activation, microwave and oxidant, green solvent, etc.), and solvent extraction have been used for the separation and extraction of rare-earth elements (REEs), such as Y, Eu, Ce, Tb, La, and Ga, from waste phosphors. In this article, we systematically summarized the research progress of commonly used separation and extraction methods for REEs in waste phosphor powders, analyzed the advantages, disadvantages, and existing problems of different methods, and proposed potential directions for future research.