Rare earth elements (REEs) are essential for high-tech and clean energy industries. Three REEs, Pr, Nd, and Dy, are critical ingredients for magnets, which are widely used in electronics, automobile, and wind energy industries. The supply chain of REEs is at risk because the production of REEs is concentrated in a few countries. One way to reduce the supply risk is to recover REEs from waste streams. Preliminary cost analysis indicates that recovering REEs from waste NdFeB magnets is economically feasible. In this study, an improved correlation for predicting the minimum column length to reach the constant-pattern state was developed for Ligand-Assisted Displacement Chromatography (LAD). Rate model simulations for developing the correlation were based on modulated multi-component Langmuir isotherms. The correlation was used to generate an improved constant-pattern design method. The rate model simulations were verified using literature data for the separation of seven REEs. The new correlation was verified using data for the separation of binary mixtures of Nd and Pr. In the separation of three REEs from waste magnets, the experimental elution profiles matched closely with rate model simulations. Three REEs in a waste magnets REE simulant was recovered with an overall yield of &gt;99% and a purity of &gt;99%. The average productivity for this system was about 100 kg/m3/day. Most of the chemicals were recycled and reused, generating little waste.

Ligand-assisted displacement chromatography for the purification of three rare earth elements from waste NdFeB magnets

Macromolecular Chemistry: The Second Century

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ACS Spring 2020 National Meeting & Expo

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.