Selective extraction and separation of Ce(IV) from thorium and trivalent rare earths in sulfate medium by an α-aminophosphonate extractant

A novel extractant, di (2-ethylhexyl) (2-((2-ethylhexyl) amino) propan-2-yl) phosphonate (DEHAPP, abbreviated as B), was synthesized for the selective extraction of Ce(IV) in sulfate medium. The effect of contact time, the H2SO4 concentration, the DEHAPP concentration and temperature on the Ce(IV) extraction were studied systematically. DEHAPP exhibits a good extraction ability towards Ce(IV) when compared with other neutral organophosphorus extractants such as Cyanex 923, Cyanex 925 and DEHEHP. The extraction equilibrium constants and thermodynamic parameters (Delta G, Delta H and Delta S) were calculated. The extraction reaction of Ce(IV) is an endo-thermic process. The extracted complexes were determined to beH(2)SO(4).B-(org) andCe(HSO4)(2)SO4.2B((org)). A extraction process to selectively recover Ce(IV) from bastnaesite leaching was proposed, by which the purity of cerium product reached 99.5% with a yield of 90.7%. (C) 2016 Elsevier B.V. All rights reserved.