Multi-dimensional ligand-assisted chromatography method for the purification of rare earth elements and other metal ions from waste magnets

Abstract

A method of recovering substantially rare earth elements (REEs) from magnets, including first dissolving a magnet to yield a solution containing Nd, Pr, and Dy, and then equilibrating a first column with Cu2+ solution to yield a first equilibrated column, introducing the solution to the first equilibrated column, and introducing a ligand solution to the first equilibrated column to establish three bands of different liquid compositions in the column, wherein the three bands comprise a Dy/Nd mixed band, a first pure Nd band, and a Nd/Pr mixed band. Next, sending the Dy/Nd mixed band to a second column containing a Cu2+ solution and introducing a ligand solution to the second column to establish a pure Dy band and a second pure Nd band in the second column, and sending the Nd/Pr mixed band to a third column containing a Cu2+ solution and introducing a ligand solution to the third column to establish a third pure Nd band and a pure Pr band in the third column. Finally, eluting the respective pure Nd bands to recover Nd, eluting the pure Dy band to recover Dy, and eluting the pure Pr band to recover Pr.