INFLUENCE OF KINETIC-PROPERTIES OF EXTRACTION SYSTEMS ON THE SEPARATION AND PRECONCENTRATION OF SOME ELEMENTS BY COUNTERCURRENT CHROMATOGRAPHY

The influence of kinetic properties of several extraction systems on t he separation of some elements by countercurrent chromatography (CCC) has been studied. The chromatographic behaviour of Eu(III), Fe(III), T a(V), Nb(V), Hf(IV), Zr(TV) has been investigated in two kinetically d ifferent extraction systems on the basis of di-2-ethylhexylphosphoric acid (D2EHPA) and tetraphenylmethylenediphosphine dioxide (DTPMDP). It has been shown that the values of mass transfer coefficients determin e the type of elution (isocratic or step), which is necessary for the element separation. The data on batch extraction (mass transfer coeffi cients and partition coefficients) and parameters of chromatographic p eaks (half-widths) can be interrelated by the expression proposed.