Soft donor extractants for use in separations of the actinide elements from the lanthanide elements in spent nuclear fuel has been of interest for many years. Ionic liquids have shown promise in actinide/lanthanide extractions due to their selectivity and chemical stability. We have been exploring the use of soft-donor containing phosphonium dithiophosphinate ionic liquids (ILs) for separation purposes. The ionic liquids [P(6,6,6,14)][iBuPS2] and [P(6,6,6,14)][Cyanex 301] (Cyanex 301 = tBuCH2CHMeCH2)2PS2) have been shown to selectively extract the uranyl moiety from the lanthanide elements in nitric acid solutions. In all extractions, the uptake of uranium into the ionic liquid phase was quantitative and the lanthanide elements remained in the aqueous phase. Speciation of the uranyl species was investigated by NMR and Raman spectroscopies. Additionally, we studied the effects of uranyl uptake by varying pH and in the presence of increased NO3- and Cl- concentrations. LA-UR-13-27848

Extraction of uranyl from the lanthanide elements in acidic media using dithiophosphinate based ionic liquids

247th National Meeting (2014)

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