A synergistic extraction strategy by Cyanex572 and Cyanex923 for Th(IV) separation

The synergistic extraction of thorium (Th) with a mixture of Cyanex572 and Cyanex923 in hydrochloric acid medium has been investigated in this paper. Cyanex572 is a novel commercial extractant produced by Cytec Industries Inc. Up to now, no synergistic extraction concerning Cyanex572 has been reported. In this study, a significant synergistic effect was indicated by the combination of Cyanex572 and Cyanex923 for Th(IV). At the acidity of 0.1 mol/L, the largest synergistic enhancement coefficient from equal mole fraction of Cyanex572 and Cyanex923 reached 5.63. Extraction mechanism of mixed Cyanex572 and Cyanex923 for Th(IV) was proposed by slope analysis method and IR spectra, the composition of extracted complexes was determined as ThCl2(HL2)2B. The synergistic extraction system has revealed a potential application value in the separation of Th(IV) from leaching solution of rare earth (RE) radioactive waste residue.