KINETICS OF EXTRACTION OF ZINC BY DI(2-ETHYLHEXYL) PHOSPHORIC-ACID IN CUMENE

Kinetic data for the extraction of zinc(II) from aqueous sulphate solutions into di(2-ethylhexyl) phosphoric acid based on Lewis-cell experiments, are presented. As solvent cumene was used. An extraction mechanism is formulated, which includes the diffusional resistances across the phase boundary. The model developed explains satisfactorily both the data obtained in this study and data from the literature. In the present study the mass transfer of the organic zinc complex was found to be the rate determining step. This was also found to be the case in other studies where the extraction rate dependency on pH and extractant concentration was equal to the equilibrium dependancy. Suggestions are made to increase the possibility for operation in the reaction controlled regime. © 1990.