Energy?efficient and cost?effective rare earth separations using membrane solvent extraction. Separation and recovery of high purity rare earth oxides from a wide range of end?of?life scrap permanent magnets. Integrated process development that demonstrates waste minimization and supports closed?loop circular economy. Process stability and reliability can enable scale?up with industrial scale modules.This study reports the process scale?up and long?term performance of an energy?efficient and cost?effective membrane solvent extraction (MSX) process for separation and recovery of high purity rare earth oxides (REOs) from scrap permanent magnets (SPMs). The rare earth elements (REEs), including dysprosium, neodymium, and praseodymium, are recovered from SPMs using a neutral extractant, tetraoctyl diglycolamide (TODGA) embedded in a microporous polypropylene hollow fiber membrane module. The MSX process performance is demonstrated with bench scale module with membrane surface area of 1.4?m2 to industrial scale modules with membrane surface area of up to 20?m2 to enable the processing of up to 1?ton?month?1 of SPMs. The purity and the yield of the recovered REOs are >99.5?wt% and >95%, respectively. The average extraction rate of REOs is >10?g?m?2?hr?1. A skid of MSX system is assembled with a membrane area of 40?m2. The MSX skid successfully recovers REOs with a capacity of 300?kg REOs/month. Finally, it is determined that the organic phase containing the extractant maintains its performance up to 250?h. The results suggest that the MSX process is an economically viable and environmentally friendly process for separation and recovery of REOs from electronic wastes.

» Author: Syed Z. Islam, Priyesh Wagh, James Eli Jenkins, Christopher Zarzana, Mac Foster, Ramesh Bhave

» Publication Date: 05/07/2022

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