Direct Selective Extraction Of Trivalent Americium From Purex Raffinate Using A Combination Of Cyme(4)Btphen And Tedga-A Feasibility Study

The direct and selective extraction of Am(III) from simulated PUREX raffinate is demonstrated using a novel combination of the lipophilic extractant CyMe(4)BTPhen (2,9-bis(5,5,8,8-tetramethyl-5,6,7,8-tetrahydrobenzo[e]-[1,2,4] triazin-3-yl)-1,10-phenanthroline) and the hydrophilic complexant TEDGA (N, N, N', N'-tetraethyl-diglycolamide) to enhance selectivity toward Am(III) extraction. Separation factors (SF) of up to SFAm/Cm = 4.9 were observed in tracer experiments using this combination of CyMe(4)BTPhen and TEDGA. Distribution ratios of stable isotopes of fission and activation products contained in a simulated PUREX raffinate solution are reported for the first time with CyMe(4)BTPhen, and some co-extracted metal ions are identified. The metal ions partly co-extracted from the simulated PUREX raffinate solution were Cu, Pd, Cd, Ag, Ni, and to a lesser extent Sn and Mo. The co-extraction of Pd and Ag was successfully suppressed using Bimet ((2S, 2' S)-4,4'-(ethane-1,2-diylbis( sulfanediyl)) bis(2-aminobutanoic acid)). The extraction was also studied as a function of the TEDGA concentration. The distribution ratios of Am and Cm can be adjusted by variation of the TEDGA concentration to yield D-Am values > 1 and D-Cm values < 1. Separation factors for Am(III) over Cm(III) of up to SFAm/Cm = 2.4 were observed in these experiments. For Ln(III) + Y(III), distribution ratios below 1 were observed, thus enabling a direct extraction of Am(III) from simulated PUREX raffinate with a sufficient selectivity against trivalent lanthanides and Cm(III).