Selective Recovery of Rare Earth Elements from a Wide Range of E-Waste and Process Scalability of Membrane Solvent Extraction.

In this study, the scalability of the supported membrane solvent extraction (MSX) process for the recovery of rare earth elements (REEs) from scrap permanent magnets was demonstrated by processing larger quantities of different scrap magnet feedstocks with a membrane area of more than 1 m2. The MSX process was successfully employed to recover high-purity REEs in their oxide form (REOs) from a wide range of end-of-life magnet feedstocks including hard disk drives (HDDs), MRI, cell phone, bonded, swarf, and hybrid car magnets. REEs with the purity of more than 99.5 wt %, recovery of more than 95%, and an extraction rate of as high as 9.3 g/(h m2) were recovered from feed solutions containing REEs of up to 46 000 mg/L. It was found that the extraction rate strongly depends on the initial REE concentration in the feed solution and to some extent on the composition of the scrap magnet source. The results demonstrated that MSX is a scalable and versatile process for the recovery of REEs from a wide range of electronic wastes.