Trivalent actinide and lanthanide cations separation using cloud point extraction

I&EC 165

Ken Czerwinski, czerwin2@unlv.nevada.edu, Department of Chemistry and Harry Reid Center, University of Nevada Las Vegas, 4505 Maryland Parkway, Las Vegas, NV 89154, Alain Favre-Réguillon, Alain.Favre-Reguillon@univ-lyon1.fr, Laboratoire de Chimie Organique, Conservatoire Nationale des Arts et Métiers, 75003 Paris, France, and Micheline Draye, Micheline.Draye@univ-savoie.fr, Laboratoire de Chimie Moléculaire et Environnement Polytech'Savoie, Université de Savoie Campus Scientifique, 73376 Le Bourget du Lac Cedex, France.
Liquid-liquid extraction is extensively employed in existing fuel cycle separations. Proposed future fuel cycles are expected to require element separations currently beyond standard practice. As a result, new separation methods based on innovative concepts are currently being developed. Thus novel liquid-phase extraction technologies, like Room Temperature Ionic Liquids, aqueous biphasic system and cloud-point extraction technique have the potential to supplement classical solvent extraction technologies in future fuel cycles. To explore the development of novel separations the use of cloud-point extraction technique for the extraction and the separation of trivalent actinide and lanthanide cations is investigated in the present study. The methodology of the separation is based on the formation of metal ion complexes soluble in a micellar phase of non-ionic surfactant. The metal ion complexes are then extracted into the surfactant-rich phase at a temperature above the cloud-point temperature. The concentration of the nonionic surfactant, the nature and type of lipophilic chelating agent and chelating agent–metal molar ratio are identified as factors determining the extraction efficiency and selectivity.