Application of ion exchange resins in gold hydrometallurgy. A tool for cyanide recycling.

The application of macroporous strong base resins to cyanide recovery from synthetic solutions containing ferrous cyanide, nickel cyanide and high lev els of copper cyanide is discussed. Adsorption experiments show that strong base resins readily extract metal cyanocomplexes, in a sequence of affinit y given by Ni>Cu>Fe, for polystyrene resins, and by Cu>Ni>Fe, with polyacry lic resins. The presence of ethyl ammonium quaternary groups results in a r emarkable low iron uptake. Acid solutions are able to desorb WAD cyanides b ut the precipitation of Prussian blue-like compounds in the presence of fer rocyanide ion poisons the resin. This work shows that iron cyanocomplexes m ay be removed with concentrated sodium chloride or sodium nitrate solutions . The role of these eluants on the desorption of copper and nickel cyanocom plexes is also discussed.