To reduce the cost and complexity of separations for closed nuclear fuel cycles, solvent extraction processes based on combined extractants are being considered. Unfortunately, strong interactions between the extractants have introduced complications in process development. In this work, 31P NMR and FTIR have been used to characterize new combinations of extractants that might be suitable for use for trivalent actinide/lanthanide separations. Adducts between Cyanex-923 and HEH[EHP] or Cyanex-272 (log KHEH[EHP] = 2.21, log KCyanex-272 = 1.44) were found to be weaker than adducts of HDEHP with either Cyanex-923 or CMPO (log KC-923 = 2.79, logKCMPO = 3.07). Most importantly, the strength of the interaction correlates with the acidity of the cation exchanging extractant. The weak interactions between Cyanex-923 and HEH[EHP] (and Cyanex-272) suggest that this combination could offer fresh options for combined extractant systems. Work supported by the USDOE FCR&RD program, Sigma Team for Minor Actinide Separations program.

Study of the interaction between Cyanex-923 and Cyanex-272, HEH[EHP], and HDEHP

245th National Meeting (2013)

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