Solvent extraction of Pr and Nd from chloride solutions using ternary extractant system of Cyanex 272, Alamine 336 and TBP

•Mixture of Cyanex 272 and Alamine 336 showed synergism on Pr and Nd extraction.•Adding TBP to this binary mixture greatly enhanced the extraction of Nd and Pr.•Highest synergistic enhancement factor was obtained at TBP mole fraction of 0.7.•The solvent extraction reaction of Nd and Pr by the ternary mixture was identified.•Metals were completely stripped from the ternary mixture by dilute acid solution.

Synergistic extraction and separation of Pr and Nd in chloride medium using a ternary mixture containing Cyanex 272, Alamine 336 and TBP has been investigated. Compared to the binary mixture (Cyanex 272 + Alamine 336), the ternary mixture showed a remarkable synergism on metals and increased the separation factor. The highest synergistic enhancement factors were obtained for Pr (17.0) and Nd (14.6). The mechanism of the synergistic extraction reaction and the role of Alamine 336 and TBP in reaction were proposed. Furthermore, metals in the ternary mixture were easily stripped by using HCl or H2SO4 solution with lower acidity.