KINETICS AND MECHANISM FOR COPPER(II) EXTRACTION FROM SULFATE-SOLUTIONS WITH BIS(2-ETHYLHEXYL)PHOSPHORIC ACID

The rate of copper(II) extraction from mol/m3 (Na,H,Cu)SO4 aqueous solution with bis(2-ethylhexyl)phosphoric acid (D2EHPA, HR) dissolved in kerosene were studied at 25-degrees-C, using a constant interfacial area cell. It was found that, under the conditions studied, the extraction rate could be satisfactorily described by the interfacial chemical reaction model accompanied by the complex diffusion in the organic stagnant film, and the stripping rate mainly by the diffusion process of the complex. In addition, it was deduced that the rate of complex formation of copper(II) with D2EHPA was controlled by the reaction of the adsorbed 1:2 copper-D2EHPA complex at the interface, CuR2, and the dimeric D2EHPA (HR)2BAR, in the organic phase adjacent to the interface.