The kinetics of U and Ce extraction by tri-n-butyl-phosphate (TBP) and
the redox potential behavior in the aqueous phase have been investiga
ted in an oscillatory extraction system. The extraction has been follo
wed continuously by UV-visible spectroscopy, potentiometry, and radioa
ctive counting methods. Data collected showed the changes of Ce4+ and
UO22+ concentrations in organic and aqueous phases with time. Uranium
actively responded to the redox potential fluctuations. The uranium di
stribution coefficient changed repeatedly and was out-of-phase with Ce
(IV) fluctuations.