Liquid-liquid microflow patterns and mass transfer of radionuclides in the systems Eu(III)/HNO₃/DMDBTDMA and U(VI)/HCl/Aliquat 336

Two phases (liquid-liquid extraction) stratified flows in a rectangular geometry are investigated in a double-Y shape glass chip. The influence of physical properties, in particular the viscosity of the two liquids, on the velocity profiles is determined numerically. Viscosity affects the shapes of the velocity profiles of each phase. The extraction conditions (acid concentrations, contact times) in batch and in the micro-fluidic device were considered for a neutral extractant, N,N'-dimethyl N,N'-dibutyl tetradecyl-malonamide (DMDBTDMA) and a liquid anion exchanger (Aliquat 336), for the extraction of Eu(III) from HNO₃ and U(VI) from HCl, respectively. The effects of viscosity and operating conditions on extraction performances were investigated, and the apparent rate constants were evaluated for the extraction of uranium by Aliquat 336 k(app) = (0.55 ± 0.03) s^-1 and for the extraction of europium by DMDBTDMA: k(app) = (2.9 ± 0.2) * 10^-3 s^-1. (authors)