Synergistic solvent extraction of neodymium form nitric acid medium using Cyanex 302 and D2EHPA

Abstract

AbstractIn this research, a binary mixture of Cyanex 302 (bis‐2,4,4 trimethylpentyl monothiophosphinic acid) and D2EHPA (di‐2‐ethylhexyl phosphoric acid) in kerosene was used for extracting neodymium from nitric acid medium. The different variables affecting the extraction of Nd(III) such as contact time, solution acidity, extractant concentration, and temperature were investigated. Stripping of neodymium ions from the loaded organic phase using HCl, HNO3, and H2SO4 for the re‐extraction of neodymium was also carried out. Results indicated that the most efficient reagent for the stripping of neodymium was nitric acid. The extraction reaction of neodymium with the synergistic mixture was determined using graphical method to be NdH5A2B6. The organo‐metallic complex containing neodymium was examined by Fourier Transform Infrared Spectroscopy (FT‐IR). The values of stoichiometric coefficients and thermodynamic parameters were calculated for this mixture. The extraction was an endothermic process, and the thermodynamic functions, ΔH and ΔS were determined to be 10.532 kJ/mol and −123.681 j/mol °K, respectively for the system under study. The Cyanex 302+D2EHPA system not only increased the extraction efficiency of neodymium but also improved the selectivity significantly. The separation factor of neodymium and praseodymium suggested that this mixture would be of practical value in the separation of neodymium.