Selective extraction and recovery of rare earth metals from waste fluorescent powder using alkaline roasting-leaching process

廖春发，黎振源，曾颜亮，陈静远，钟立钦，王莉

Metallurgical and Chemical Engineering Institute, Jiangxi University of Science and Technology

摘 要：Waste management of rare earth metals（REMs） containing materials and recycling of rare earth metals（REM） from waste materials are becoming more and more important due to high demand and resource exhaustion. However, extraction of REM from waste fluorescent powder materials is difficult because of their special aluminate structure. A novel "alkaline roasting-acid leaching" process was developed in this study. The alkaline roasting process mechanism was examined using differential thermal analysis（DTA）-thermogravimetric（TG） measurements, and the roasting product was characterized by XRD analysis. In this process, Al₂O₃ was converted into water soluble NaAlO₂ via alkaline roasting, and NaAlO 2 in the roasting product could be easily dissolved in water, while the rare earth oxide（REOs） remained as solid. After filtration, REOs cake was leached using hydrochloric acid to achieve 99.8% of REM recovery. It was concluded that the alkaline roasting-acid leaching process could effectively separate Al₂O₃ and REOs with high REM recovery.

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