The uranium extraction kinetics with Di-2-Ethyl Hexyl Phosphoric Acid-Tri Butyl Phosphate (D2EHPA-TBP) and Di-2-Ethyl Hexyl Phosphoric Acid-Tri Octyl Phosphine Oxide (D2EHPA-TOPO) dissolved in dodecane has been investigated. The objective of the present study was to identify the reaction location, reaction regime, reaction orders with respect to the reactants and the intrinsic rate constant of the reaction. Experiments were carried out in a constant interfacial area stirred cell and the parameters were varied over a range of 1 < impeller speed < 1.5r/s, 0 < temperature < 50 degrees C, concentration of reactants, 3.12 x 10(-4) < V-aq/V-o <6 x 10(-4) m(3) and effective interfacial area (13.62 < S/V-aq < 40.85 m(-1)). Experimental results with effects of impeller speed, aqueous phase volume, interfacial area and temperature indicate an interface to be the location of reaction. The overall rate is controlled by both the intrinsic kinetics and the mass transfer of the species involved. The overall rare of the reaction is given by the following equation: d[B](aq)/dt = [B](aq) (S-kf/V-aq [A](o)(m)[AC](o)(q)[H+](aq)(p)+Sk(h)/V-o[A](o)(m-2)[AC]o(q-z)[H+](aq)(p+z)) -Sk(b)/V-o[B](aq.t) (=) (0)[A](o)(m-z)[AC](o)(q-z)[H+](aq)(p+z)/(1+[A](o)(m)[AC](o)(q)[H+](aq)(p)(k(f)/k(Laq))+[A](o)(m-z)[AC]o(q-z)[H+](aq)(p+z)(k(b)/k(Lo))) A systematic procedure has been developed for the estimation of intrinsic kinetics and the mass transfer coefficients. (C) 2013 Elsevier Ltd. All rights reserved