Towards efficient and selective boron recovery from end-of-life rare earth permanent magnets using an ionic liquid

The growing demand for neodymium-iron-boron (NdFeB) magnets necessitates efficiently recovering boron from leach solutions in recycling processes. This study synthesized and characterized the [TOA][P204] ionic liquid (IL) for selective boron extraction from a citrate-based leach solution of spent NdFeB magnets. Key parameters, including IL concentration, diluent type, aqueous-to-organic volume ratio, and pH, were systematically investigated, while stripping studies identified optimal reagents for boron recovery. [TOA][P204] exhibited high selectivity, extracting ∼82 % of boron with minimal uptake of rare earth elements, except dysprosium (5 %) and iron (8 %). Alkaline stripping recovered both boron and iron, whereas hydrochloric acid (HCl) achieved nearly 100 % boron recovery with negligible iron removal. This work establishes [TOA][P204] as an efficient extraction medium for NdFeB recycling, addressing boron-related environmental concerns while improving economic feasibility and supporting circular economy strategies for critical materials.