Bestimmung von Verteilungsverhältnissen von Uran(IV) mit Hilfe der Extraktionschromatographie in dem System: unverdünntes Tri-n-butylphosphat und wäßrige Salpetersäure

The distribution ratio of U(IV),D _U(IV), between undiluted tri-n-butyl phosphate and aqueous nitric acid has been determined by means of extraction chromatographic columns. The separation factor, β, of U(VI) and U)IV) (defined as the ratio of the distribution ratios,D, \(\beta = \frac{{D_{U(VI)} }}{{D_{U(IV)} }}\) ) was obtained experimentally via the retention volumes.D _U(VI) is known from the literature andD _U(IV) was calculated. TheD _U(IV)-values agree with those obtained by batch experiments, the reproducibility was even better. The stability of U(IV) in the chromatographic columns is good. In the very rare cases, in which U(IV) was oxidized to U(VI) during the experiment, this can be recognized from the shape of the elution curve, because the U(IV) peak shows a tailing. As long as the U(IV) peak is visible, even these experiments can be evaluated which was not possible in batch experiments.