Synergistic extraction and recovery of Cerium(IV) and Fluorin from sulfuric solutions with Cyanex 923 and di-2-ethylhexyl phosphoric acid

Abstract Synergistic extraction and recovery of Cerium(IV) (Ce(IV)) and Fluorin (F) from sulfuric solutions using mixture of Cyanex 923 and di-2-ethylhexyl phosphoric acid (D2EHPA) in n -heptane have been carried out. In order to investigate the synergistic extraction of Cyanex 923 + D2EHPA, extraction Ce(IV), F, Ce(III) and Ce–F mixture solution using D2EHPA or Cyanex 923 as extractant alone were studied firstly, and then Synergistic extraction of Ce(IV), F and Ce(IV)–F mixture solution with D2EHPA + Cyanex 923 were carried out. The largest synergistic coefficient of Ce(IV) is obtained at the mole fraction X Cyanex 923  = 0.8. The synergistic enhancement coefficients ( R max ) obtained for Ce(IV) are 23.12 in Ce(IV) solution, and in Ce–F mixed solution R max for Ce(IV) and F are 2.24 and 3.25 respectively. Furthermore, the beta values at X Cyanex 923  = 0.8 were Ce(IV)/Ce(III) = 1321.18, CeF 2 2+ /Ce(III) = 36.35, which means that Ce(IV), CeF 2 2+ can be effectively separated from Ce(III). Ce(IV) and CeF 2 2+ would form the new complexes as Ce(HSO 4 ) 2 A 2 1.5B and CeF 2 (HSO 4 )A2B in the mixture system, respectively. However Ce(III) could not be extracted by the mixture system at the experimental conditions. The potential application of the mixture system to separate Ce(IV) and F from bastnasite has also been discussed.