Solvent extraction of lanthanides(III) from chloride and nitrate media with di(2-ethylhexyl) phosphoric acid and ionic liquids in three-component biphasic solvent systems

In this paper, as an alternative to the traditional extraction systems, multicomponent biphasic solvent systems used in liquid-liquid chromatography are suggested for application in hydmmetallurgy. Three-component biphasic solvent system (1:1:1) consisting of water, hexane, and isopropyl alcohol was tested for the extraction of lanthanides(III) from chloride and nitrate media by adding different extractants to the system. Di(2-ethylhexyl)phosphoric acid (D2EHPA) and mixtures of ionic liquids (IL) dissolved in hexane were investigated as extractants. Results showed that the extraction efficiency of Ln(III) with D2EHPA increases with the addition of sodium acetate or a mixture of CH3COONa and CH3COOH. Extraction of lanthanides(III) with mixtures of various IL from 0.5 M solutions of NaCl or NaNO3 was examined. Effective separation of Ln(III) was observed by using a mixture of trioctylammonium di(2-ethylhexyl)phosphate and dicyclohexylammonium caprylate (2:1), whereas by using a mixture of trioctylammonium caprylate and dicyclohexylammonium di(2-ethylhexyl) phosphate (2:1) the Ln(III) separation did not occur.

Automated summary

This study explores the use of multicomponent biphasic solvent systems in liquid-liquid chromatography for extracting lanthanides in hydrometallurgy. It was found that the addition of sodium acetate or mixtures can enhance the extraction efficiency, and effective separation methods were observed in the experiments.