Oscillatory extraction - a new method of similar elements and isotopes separation

Data demonstrating the possibility of isotope separation by oscillatory extraction are presented. The experimental setup consisted of two extractors coupled by a bulk liquid membrane (extractant: 0.5 M TBP in tetradecane). The oscillatory extraction method is based on exploiting small kinetic differences between isotopes during competitive extraction driven by the Belousov-Zhabotinskij (BZ) reaction. The oscillations of Ce(III) and Ce(IV) concentrations during BZ reaction induce oscillations of the extractant equilibrium concentration. This leads to differences in the isotope distribution between the aqueous and organic phases. The organic phase is enriched with the 'light' isotope and after stripping to the other aqueous phase it is also enriched with this isotope. A possible explanation is based on the fact that due to the differences in the isotope properties in the extraction and complexation kinetics, differences occur in the average concentrations of the isotopes in the organic phase. The processes result in differences in the isotope concentrations in the different extractors. Separation of 142Ce and 140Ce between the aqueous phases of two extractors coupled by a bulk liquid membrane in the experiments with cyclic chemical oxidation/reduction with the enrichment factor of about 2.5 % was achieved. In the same experiment and under the same conditions, the Nd isotopes were separated (heavy isotopes of Nd - 144Nd, 145Nd, 146Nd, 148Nd and 150Nd from the light isotope - 143Nd) with an enrichment factor of about 0.7-1.4 %