THE EFFECT OF RESIN STRUCTURE ON THE LOADING OF COPPER AND IRON CYANO COMPLEXES

Abstract

This study on two commercially available ion exchange resins is relevant to the recycling of cyanide from ores containing high levels of copper. The effects of resin structure and matrix on the sorption of copper and iron cyanocomplexes were stud-ied using synthetic solutions in the presence of two different 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 HP555s resin sorbed only the Cu(CN)₄ ⁻³ complex while the polyacrylic resin (Amberlite IRA958) loaded both complexes. There was no change in the speciation 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 probabilistic mathematical model was used to describe the equilibrium sorption of copper and iron cyanide complexes on both resins. Using this model a higher sorption energy for copper than iron was observed for the Imac HP555s resin. In contrast, a lower sorption energy for copper than iron was observed for the Amberlite IRA958 resin. The values of the model parameters were related to the features of each complex. The results suggest that the Imac HP555s resin should be used for the recycling of cyanide from solutions containing a high level of copper, while the Amberlite IRA958 resin is recommended to treat streams containing high levels of iron.

ACKNOWLEDGMENTS

This work was supported by Conselho Nacional de Pesquisas, CNPq, Brazil and by RECOPE and PRONEX grants. The assistance of Dr. Shane Huntington from the Particulate Fluids Processing Centre (PFPC), The University of Melbourne is also appreciated.