The Effect of Complexing Agent on the Extraction of Lanthanides by Di(2-Ethyl Hexyl) Phosphoric Acid. II. 3-Mercapto Propionic Acid

Abstract

Liquid-liquid extraction/HDEHP / 3-mercapto propionic acid/Nd-147, Tb-160, Tm-170 Summary Liquid-liquid extraction of neodymium, terbium and thulium by di(2-ethyl hexyl) phosphoric acid (HDEHP) in the presence of 3-mercapto propionic acid has been studied. The effect of nitric acid on the distribution ratios of the metal ions has been explained by means of the equilibria involved in the system. A possible mechanism of extraction and the effect of 3-mercapto propionic acid on the separation of lanthanides are discussed.In order to assess the effect of different types of complexing agents on the extraction and separation of lanthanides by HDEHP, a complexing agent of a different kind, e. g., 3-mercapto propionic acid (MPA), has been chosen in this investigation. In contrast to glycine, 3-mercapto propionic acid forms a positively charged complex with rare earth metal ions. In the present work, neodymium, terbium and thulium were chosen for a representative evaluation of the extraction pattern of the rare earths as a whole.