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Magnetic Field Directed Rare‐Earth Separations
Author(s) -
Higgins Robert F.,
Cheisson Thibault,
Cole Bren E.,
Manor Brian C.,
Carroll Patrick J.,
Schelter Eric J.
Publication year - 2020
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201911606
Subject(s) - rare earth , paramagnetism , ionic radius , lanthanide , chemistry , ion , analytical chemistry (journal) , magnetic separation , fraction (chemistry) , earth (classical element) , materials science , mineralogy , physics , condensed matter physics , chromatography , organic chemistry , metallurgy , mathematical physics
The separation of rare‐earth ions from one another is challenging due to their chemical and physical similarities. Nearly all rare‐earth separations rely upon small changes in ionic radii to direct speciation or reactivity. Herein, we show that the intrinsic magnetic properties of the rare‐earth ions impact the separations of light/heavy and selected heavy/heavy binary mixtures. Using TriNOx 3− ([{(2‐ t BuNO)C 6 H 4 CH 2 } 3 N] 3− ) rare‐earth complexes, we efficiently and selectively crystallized heavy rare earths (Tb–Yb) from a mixture with light rare earths (La and Nd) in the presence of an external Fe 14 Nd 2 B magnet, concomitant with the introduction of a concentration gradient (decrease in temperature). The optimal separation was observed for an equimolar mixture of La:Dy, which gave an enrichment factor of EF La:Dy =297±31 for the solid fraction, compared to EF La:Dy =159±22 in the absence of the field, and achieving a 99.7 % pure Dy sample in one step. These results indicate that the application of a magnetic field can improve performance in a molecular separation system for paramagnetic rare‐earth cations.