APPLICATION OF ION EXCHANGE RESINS IN GOLD HYDROMETALLURGY. A TOOL FOR CYANIDE RECYCLING.

Abstract

The application of macroporous strong base resins to cyanide recovery from synthetic solutions containing ferrous cyanide, nickel cyanide and high levels of copper cyanide is discussed. Adsorption experiments show that strong base resins readily extract metal cyanocomplexes, in a sequence of affinity given by Ni>Cu>Fe, for polystyrene resins, and by Cu>Ni>Fe, with polyacrylic resins. The presence of ethyl ammonium quaternary groups results in a remarkable low iron uptake. Acid solutions are able to desorb WAD cyanides but the precipitation of Prussian blue-like compounds in the presence of ferrocyanide ion poisons the resin. This work shows that iron cyanocomplexes may be removed with concentrated sodium chloride or sodium nitrate solutions. The role of these eluants on the desorption of copper and nickel cyanocomplexes is also discussed.