Brecht Dewulf and Koen Binnemans from KU Leuven have published new work in RSC Advances (May 2025) exploring how polar organic solvents can boost the efficiency and selectivity of rare-earth element (REE) separations. Their research compares ion exchange, extraction chromatography, and solvent extraction in non-aqueous systems, offering new directions for sustainable solvometallurgical processes.
The study evaluated the performance of Amberlite IRA 402, TEVA, and DGA resins in various solvents including ethanol, ethylene glycol, water, and formamide. Notably, Amberlite IRA 402 efficiently recovered transition metals like iron, copper, and cobalt, while DGA resins showed clear selectivity for REEs, particularly in separating heavy from light rare earths. The results confirmed that lower dielectric constants (e.g., ethanol) enhanced metal uptake, pointing to the powerful role of solvent polarity.
In comparison, solvent extraction using Aliquat 336 and TODGA suffered from mutual miscibility issues—highlighting a practical advantage of solid-phase resins in non-aqueous media. Still, the study warns that extractant leaching from physically bound resins (TEVA and DGA) can reduce efficiency, especially in ethanolic conditions.
This work underscores solvometallurgy’s potential to enable safer, greener rare-earth processing, offering insights into how solvent choice and resin stability influence performance.
Reference:
B. Dewulf, K. Binnemans. Effect of polar organic solvents on the separation of rare earths and transition metal chloride complexes: comparison of ion exchange, extraction chromatography and solvent extraction. RSC Adv., 2025. https://doi.org/10.1039/d5ra00908a
Acknowledgements:
This research was supported by SIM² KU Leuven and the European Research Council (ERC). The authors thank the SOLVOMET group for technical support.
