Multistage extraction separation of Am(III) and Cm(III) in planet centrifuges

Abstract

Countercurrent chromatography (CCC), a support-free partition chromatography, allows realization of multistep extraction separations in specially designed planet centrifuges. Highly efficient Am(III)/Cm(III) separation in nitric acid solutions in the dynamic mode was obtained using two-phase systems based on diamide extractants such as N, N′-dimethyl-N,N′-dibutyltetradecylmalonamide (DMDBTDMA), N,N′-dimethyl-N,N′-dioctylhexylethoxymalonamide (DMDOHEMA), and N,N′-dimethyl-N,N′-dibutyldodecylethoxymalonamide (DMDBDDEMA). All these extractants could be recommended to use for CCC separation of 243Am and 244Cm. Increasing coil length and decreasing pumping rate of the mobile phase increase the stationary phase retention in the column and improves the resolution of the Am(III) and Cm(III) elution curves. The basic chromatographic parameters of the column (number of theoretical plates and peak resolution of the elements to be separated) are optimized. CCC could be used for separation of elements with similar properties and also for testing quality of radionuclidic products. Single-stage chromatographic separation, when realized under optimal conditions, gives the Cm fraction containing 99.5% Cm(III) and 0.6% Am(III), and the Am fraction containing 99.4% Am(III) and 0.5% Cm(III). Separation is carried out by the isocratic elution method.