Goldcarb WSC-207C GR activated carbons with platinum and palladium complexes adsorbed from aqueous solutions of K 2 [Pt(CN) 4 ], K 2 [Pt(CN) 6 ], and K 2 [Pd(CN) 4 ] were studied by the methods of X-ray photoelectron spectroscopy and IR spectroscopy with Fourier transformation, and also by MALDI massspectrometry. Platinum and palladium cyanide complexes are not reduced onto surface of active charcoal while adsorption. A certain part of the [Pd(CN) 4 ] 2-and [Pt(CN) 4 ] 2-anions directly bound to active centers on the activated carbon is oxidized more deeply and functions as particles-anchors, forming oligomers resembling Krogmann salt. A correspondence between the structure of the complex cyanometallate ion and a mode of its binding with active carbon is found. The adsorption of complex species with a linear structure or a square planar structure is defined by a possibility of the formation of donor-acceptor and metallophilic bonds. The mode of the anion [Au(CN) 2 ] -binding with the surface of active carbon was considered.In last 30 years a stable interest arose to the application of activated carbons in hydrometallurgical processes. First of all, it is connected with industrial usage of coals as main adsorbents for extraction of gold(I) from cyanide solutions and pulps. In spite of it the reason of a selective sorption of gold(I) cyanide complex on carbon adsorbents is not yet elucidated at present. Unlike the corresponding complexes of gold, adsorption of platinum and palladium cyanide complexes is by no means studied though the knowledge of specificity of their behavior in relation to carbon adsorbents can present both theoretical and practical interest. This interest is connected, firstly, with the study of mechanisms of binding complexes of noble metals with active carbons and also with the search for methods improving kinetic and capacity properties of carbon adsorbents and increasing their selectivity. Results of such studies promote the improvement of the process of mining and refining platinum metals and gold.Depending on the nature of a central atom and its ligand environment, and also on the composition of a solution and conditions, in which transition metal complexes contact carbon adsorbents, partial or complete reduction of a metal center and (or) chemisorption, which is accompanied by a change in its oxidation state, can occur at the adsorption. To predict a possible result of the interaction between activated carbon and complexes of noble metals, it was suggested to use a comparison of working and stationary potentials of coal in a solution with appropriate redox potentials of complex compounds [1]. The nature of adsorbate at the adsorption of transition metal complex compounds on activated carbons depends on several factors. The composition

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Possibility of using strongly basic anion exchange resin of MINIX brand and weakly basic anion exchange resin Purogold S992 brand in the high-temperature-caustic conditioning (HiTeCC) technological process for diminishing the loss of gold via adsorption on natural organic carbon-containing substances (pregrobbing phenomenon) in the course of cyanide leaching was studied. It was shown that the strongly basic anion exchanger MINIX has a higher affi nity for the anion [Au(CN) 2 ] -, compared with the microporous activated carbon WSC-207C-GR. As a result, the adsorbed dicyanoaurate(I) anion is transferred from the activated carbon to the ion-exchange resin. Reasons for binding of the dicyanoaurate(I) anion with active centers of activated carbons are considered, based on the fact that the adsorbent contains carbene-like carbon atoms. The existence of paramagnetic centers belonging to carbon atoms in the activated carbon was demonstrated by the EPR method. The suggested concept was used to diminish the loss of gold via partial oxidation of metallic gold in autoclave processing of pyrite-and arsenopyrite-containing concentrates.

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