The extration kinetics of Pd(II) and Au(III) from HCl (1 mol.cm-3) medium with dioctyl sulfoxide (DOSO) were measured by useing a constant interfacial stirring cell which can measure the kinetic data continuously and automatically. The interfacial and distribution characteristics of DOSO as well as the influences of several parameters, such as stirring rate, concentration, temperature, and ratio between interfacial area and phase vol. on the rate of extration were studied. The results show that the extration is controlled kinetically by interfacial chem. reaction regime (for Pd) and by diffusion or chem. reaction-diffusion mixed regime (for Au) resp. The difference of extration kinetics between Pd(II) and Au(III) with DOSO was explained.

Key words: GOLD, DYNAMICS, EXTRACTION, EXTRACTION EQUILIBRIUM, PALLADIUM, ACTIVATION ENERGY, SULFOXIDE P