In order to further reduce toxicity of nuclear waste, the French Commissariat � l'�nergie atomique et aux �nergies alternatives (CEA) is developing processes that allow separation of minor actinides from fission products. The DIAMEX (Diamide extraction) - SANEX (Selective actinide extraction) process is based on a mixture of two organic extractants: a malonamide, the N,N'-dimethyl-N,N'-dioctylhexylethoxymalonamide (DMDOHEMA) and a dialkylphosphoric acid, the di(2-ethylhexyl)phosphoric acid (HDEHP), dissolved in an alkane. The mechanisms of its extraction process are still not completely understood. Various complementary analytical techniques were used to identify and characterize americium(III) and lanthanide(III) metallic complexes formed in the organic phase after solvent extraction (UV-Visible, Infrared, NMR and Time-Resolved Laser-Induced Fluorescence spectroscopy, as well as Electrospray Ionization Mass Spectrometry). These speciation studies were performed under a variety of experimental conditions (influence of the extractants concentration, acidity of the aqueous phase�) and mixed species including the two extractants were observed.

Characterization of americium(III) and lanthanide(III) complexes in mixed solvent extraction systems containing a malonamide and a dialkylphosphoric acid

245th National Meeting (2013)

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