Journal of Sustainable Metallurgy

, Volume 3, Issue 1, pp 73–78

Separation of Rare Earths by Solvent Extraction with an Undiluted Nitrate Ionic Liquid

Thematic Section: Green Rare Earth Elements--Innovations in Ore Processing, Hydrometallurgy, and Electrolysis

DOI: 10.1007/s40831-016-0074-4

Cite this article as:
Larsson, K. & Binnemans, K. J. Sustain. Metall. (2017) 3: 73. doi:10.1007/s40831-016-0074-4


A solvent extraction system based on the ionic liquid tricaprylmethylammonium nitrate, [A336][NO3], has been investigated for separation of mixtures of rare earth elements (REE) at high total REE concentrations (up to 2 M). The chelating agent EDTA was added to the aqueous nitrate feed solution to increase the separation factors (SFs). This improvement of the SFs is based on the fact that [A336][NO3] extracts the light REE (LREE) stronger than the heavy REE (HREE), whereas a chelating agent forms more stable complexes with the HREE than with the LREE. The combination of these two effects makes that the LREE are even more efficiently extracted than in the absence of a chelating agent. The most efficient separation of the LREE La–Nd from the other REE was obtained using a total initial REE concentration of 1 M, an EDTA concentration of 0.2 M, and a total nitrate concentration of 11 M. Stripping of the extracted REE from the ionic liquid phase could be done using water.


Ionic liquids Hydrometallurgy Lanthanides Rare earths Solvent extraction 

Copyright information

© The Minerals, Metals & Materials Society (TMS) 2016

Authors and Affiliations

  1. 1.Department of ChemistryKU LeuvenHeverleeBelgium

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