Separation and Recovery of Dysprosium and Neodymium from Waste Neodymium Magnet Using Solvent-Impregnated Resin

Abstract

The separation and recovery of dysprosium (Dy) and neodymium (Nd) from waste Nd magnet was investigated using a solvent-impregnated resin loaded with 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester. The leaching solution obtained from the magnet contained Dy and Nd, together with a large amount of iron (Fe). Since Fe suppressed the adsorption of Dy and Nd, ascorbic acid was added to the leaching solution to reduce Fe(III) to Fe(II), enabling their selective adsorption. Although the separation of Dy and Nd was difficult using the conventional frontal separation mode in column operation, the separation was achieved in the gradient elution mode. The proposed separation and recovery process, based on a connected column system, yielded Dy with a purity of 98.9 wt% and a recovery yield of 96.9%, and Nd with a purity of 96.2 wt% and a recovery yield of 95.6%.