<p>The study of liquid–liquid extraction reactions has always presented challenges due to the difficulty of real-time phase analysis. Consequently, kinetic investigations of these reactions, which are crucial for understanding mechanisms and reaction rates, have been limited. This research employs online analysis of ion concentrations through easily performed pH and electrical conductivity (EC) measurements, along with a modified Lewis cell, to examine the kinetics of copper solvent extraction using an aldoxime-based extractant CLX-5640. Multiple verifications were performed to determine whether chemical reaction control or diffusion control dominates the kinetic regime. Comprehensive experiments, investigating concentration and temperature variations and activation energy verification, were performed to determine reaction mechanisms. The investigation of initial rate dependency on agitation, heterogeneous reaction model fitting, and analysis of Fick’s second law revealed chemical reaction control from a threshold of 200 rpm agitation. Reaction mechanism was thoroughly presented via a second-order rate equation with an activation energy of 44.2 kJ/mol. By conducting experiments that varied the initial concentrations of the reactants, the validity and robustness of the proposed reaction rate and mechanism were further reinforced. These results indicate that the rate constant is not significantly influenced by the initial concentrations.</p> Graphical Abstract <p></p>