The effect of resin structure on the loading of copper and iron cyano complexes

This study on two commercially available ion exchange resins is relevant to the recycling of cyanide from ores containing high levels of copper. The e ffects of resin structure and matrix on the sorption of copper and iron cya nocomplexes were studied using synthetic solutions in the presence of two d ifferent concentrations of free cyanide. Despite the presence of Cu(CN)(3)( -2) and CU(CN)(4)(-3) in solution, Raman studies indicated that the Imac HP 555s resin sorbed only the Cu(CN)(3)(-2) complex while the polyacrylic resi n (Amberlite IRA958) loaded both complexes. There was no change in the spec iation of the ferrocyanide complex during sorption on the Amberlite IRA958 resin. However, it was found that the ferrocyanide complex was oxidized to the ferricyanide complex in order to sorb on the Imac HP555s resin. A proba bilistic mathematical model was used to describe the equilibrium sorption o f copper and iron cyanide complexes on both resins. Using this model a high er sorption energy for copper than iron was observed for the Imac HP555s re sin. In contrast, a lower sorption energy for copper than iron was observed for the Amberlite IRA958 resin. The values of the model parameters were re lated to the features of each complex. The results suggest that the Imac HP 555s resin should be used for the recycling of cyanide from solutions conta ining a high level of copper, while the Amberlite IRA958 resin is recommend ed to treat streams containing high levels of iron.