Abstract
The rate of metal extraction by chelating agents was formulated by taking into account the reaction processes in the aqueous phase and in the interfacial zone, in order to understand systematically the complicated features of extraction kinetics. The interfacial reaction rate was expressed in term of rate constants of the reaction in aqueous solution. The rate of metal extraction was expressed with use of the resistances in the stagnant films, in the interfacial zone, and in the aqueous bulk phase. The solubility of the chelating agent in the aqueous phase is important for explaining the complex characteristics of metal extraction. It is essential for interpreting the characteristics of the extraction rates in the less soluble chelating agent system that the metal complex in neutral form is produced in the interfacial zone by reaction between the adsorbed metal complex cation and the chelating agent dissolved in the aqueous phase.
