Extraction of Gd, Tb, and Dy from nitrate media with a mixture of technical di-2-ethylhexyl phosphoric acid and tributylphosphate

Abstract

The extraction of medium–heavy rare-earth elements, such as gadolinium (Gd), terbium (Tb), and dysprosium (Dy), with extractant mixtures that comprise technical di-2-ethylhexyl phosphoric acid (D2EHPA) and tri-n-butyl phosphate (TBP) has been investigated individually and in their simultaneous presence. Synergistic coefficients and separation factors of the Tb/Gd, Dy/Gd, and Dy/Tb pairs of elements have been calculated. The mathematical simulation of the extraction isotherm has been performed based on the example of Gd and some assumptions about the chemical composition of the extracted complexes have been made.