Competitive Adsorption of Gold Cyanide and Organic Compounds onto Porous Adsorbents

Abstract

Activated carbon has had a tremendous impact on the technology of gold recovery from leached liquors. Ion-exchange resins have been proposed as possible alternatives to carbon, while ion-exchange fibers and membranes were investigated recently as adsorbents for metal recovery in view of their fast rate of uptake. This paper deals with the competitive adsorption of organic compounds and gold cyanide onto activated carbon, ion-exchange resin, ion-exchange fiber, and membrane. Loadings of organic compounds were measured on gold equilibrated adsorbents and compared to loadings on virgin adsorbents. Both the kinetic and equilibrium parameters in a film/surface diffusion model were affected, which indicated a competitive type of mechanism between gold cyanide and organic compounds. A two-component Freundlich-type isotherm fitted the equilibrium for adsorption on carbon, membrane, and fiber. Furthermore, low molecular mass organic substances revealed a smaller inhibiting effect on gold adsorption than long-chain or high molecular mass organic compounds.