Solvent Extr. Ion Exch.

The cobalt(LI) extraction kinetics and mechanism with EHEHPA (2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester) were investigated by an improved constant interfacial area stirred cell. The effects of the buffer species, stirring rate, temperature, specific interfacial area and surfactants on the extraction rate showed that the extraction regime was dependent on the extraction conditions and the most probable reaction zone was at the liquid-liquid interface. This extraction process was reaction controlled at lower concentration of the reactants, while it was mixed chemical reaction-diffusion or diffusion controled only for higher concentration of the reactants. An interfacial extraction reaction model with diffusion was derived. The kinetics of the extraction process was simulated with this model.The cobalt(LI) extraction kinetics and mechanism with EHEHPA (2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester) were investigated by an improved constant interfacial area stirred cell. The effects of the buffer species, stirring rate, temperature, specific interfacial area and surfactants on the extraction rate showed that the extraction regime was dependent on the extraction conditions and the most probable reaction zone was at the liquid-liquid interface. This extraction process was reaction controlled at lower concentration of the reactants, while it was mixed chemical reaction-diffusion or diffusion controled only for higher concentration of the reactants. An interfacial extraction reaction model with diffusion was derived. The kinetics of the extraction process was simulated with this model