Rare Earth Separations

Rare earth metals are ubiquitous and indispensable materials used in a wide range of technologies including smartphones, wind turbines, and electric vehicles. Due to the growth of these applications and challenges of the supply chain, new strategies for recycling of rare earths from end of life materials is an important and emerging goal as stated by both the U.S. Department of Energy and the E. U. Commission.1 Because of their chemical similarities, the separation of rare earth metals is an energy- and waste-intensive process. More than 50% of the cost of recycling rare earths from end of life materials is consumed by purification of individual rare earths from this mixture using solvent extraction, is not currently economically viable.2

Our group has developed a new class of ligands in this context based on hydroxylamines. The TriNOx3- ligand was demonstrated in a new separation system for neodymium and dysprosium, two elements found in permanent magnets and used in wind turbines. Our laboratory is continuing this effort in the development of new processes for the separation of rare earth metals to diversify the supply chain for these key elements.

Selected Publications

  • Bogart, J. A.; Cole, B. E.; Boreen, M. A.; Lippincott, C. A.; Manor, B. C.; Carroll, P. J.; Schelter, E. J. Natl. Acad. Sci. USA 2016, 113 (52), 14887-14892.
  • Bogart, J. A.; Lippincott, C. A.; Carroll, P. J.; Schelter, E. J. Chem. Int. Ed. 201554, 8222–8225.
  • Lee, H. B.; Bogart, J. A.; Carroll, P. J.; Schelter, E. J. Commun. 2014, 5361–5363.
  • Bogart, J. A.; Lewis, A. J.; Medling, S. A.; Piro, N. A.; Carroll, P. J.; Booth, C. H. Schelter, E. J. Chem. 201352, 11600–11607.


  1. U. S. Department of Energy. Critical Materials Strategy; Washington, D.C., 2011; pp 1–196.
  2. Gupta, C. K.; Krishnamurthy, N. Int. Mater. Rev. 1992, 37 (5), 197-248.