Separation process of dysprosium and neodymium from waste neodymium magnet

Separation of neodymium (Nd3+), praseodymium (Pr3+), and dysprosium (Dy3+) from a waste Nd magnet has been investigated using a solvent-impregnated resin (SIR) containing 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester coated with polyvinyl alcohol crosslinked by glutaraldehyde. A large amount of the iron (Fe3+) contained in the Nd magnet was completely separated from the rare earth metals by adding oxalic acid. Rare earth metal oxides were then prepared by calcining the rare earth metal oxalate precipitates. Separation of Dy3+ and Nd3+/Pr3+ was performed from nitrate media containing the rare earths oxides using a chromatographic separation system combined with frontal adsorption, scrubbing, and elution. Complete separation of Dy3+ was achieved and the effluent containing Nd3+ and Pr3+ was collected. Finally, separation of Nd3+/Pr3+ was performed using the same chromatographic separation system to obtain 91.0% purity Nd3+.