U(VI) back-extraction trials for measurement of U(VI) mass transfer efficiency in single stage centrifugal contactor

Sano, Yuichi   ; Shibata, Atsuhiro  ; Koizumi, Tsutomu; Koyama, Tomozo; Fox, D.*; Carrott, M.*; Taylor, R.*

Based on the U(VI) back-extraction experiments with the miniaturized single stage centrifugal contactor, effects of the total flowrate, the rotor speed and the temperature on the U(VI) mass transfer efficiency were discussed. The relationship between the U(VI) mass transfer efficiency and the residence time suggested that the U(VI) back-extraction system with the centrifugal contactor could be treated as a perfectly stirred continuous reactor. It is considered that the variations of the mass transfer efficiency were caused by the flow pattern change from the laminar flow to the turbulent flow with increasing of the rotor speed in the centrifugal contactor. In the U(VI) back-extraction under the high rotor speed condition, no significant temperature dependence of the apparent overall transform coefficient was observed. In the U(VI) back-extraction under the low rotor speed condition, temperature dependence of the apparent overall transform coefficient seemed to be larger than under the high rotor speed condition, and it suggested a chemical-step contribution in this system. Such a difference of the temperature dependence of the apparent overall transform coefficient between these experiments might be caused by the change of solvent extraction environments in the centrifugal contactor with the variation of the rotor speed.