STUDIES ON THE ADSORPTION OF SILVER FROM CYANIDE SOLUTIONS BY FUNCTIONAL POLYMERS

The adsorption of silver and copper cyanides by various functional polymers (conventional anionites, exchangers with modified amino alkyl group and S-or S,N-modified polystyrene) has been investigated. The maximum silver and copper adsorption as well as the Cu/Ag ratio on the resin have been determined. In addition, IR measurements have been carried out to determine the kind of bonding of the metal cyanides. Resins containing protonated or quaternary amino groups adsorbed the metal cyanides by a pure ion-exchange mechanism. Other resins containing thioamide or SH-fragments adsorbed the silver complex by direct interaction with the Ag+ cation. The selectivity of the resins for silver, which was determined in the system Ag/Cu cyanide was increased in the following order by a)modifying the amino groups, b)using weakly basic resins and c)using S,N-modified polystyrene, with the capacity for silver having been decreased in the same order. The reasons for that are discussed. The response of the silver cyanides to anionites is compared with that of gold cyanides.