Abstract
Residual cyanide in cyanidation tailings can be detoxified by its oxidation to cyanate, as in the Inco and Degussa processes. However, cyanate, the product of detoxification and other oxidation processes, may be reduced to cyanide in reducing environments, e.g., deepwater discharge of cyanidation tailings. This study shows that the reduction of cyanate to cyanide occurs and that the reduction rate increases with decreasing solution redox potential. Solutions with lower pH favor the reduction rate. No significant difference was observed between the results of tests prepared with distilled water and seawater, and the presence of cyanidation solid tailings does not show an effect on the reduction. Because cyanate can be reduced to toxic cyanide, causing environmental concerns, the deepwater discharges of cyanidation tailings must be handled carefully.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Bucknam, C.H., 1997, “Cyanide solution detoxification jar tests,” Global Exploitation of Heap Leachable Gold Deposits, Proceeding of TMS Annual Meeting, pp. 191–204.
Dziewinski, J., Zawodzinski, C., and Smith, W.H., 1995, “Electrochemical treatment of mixed wastes,” Proceeding of the International Conference on Radioactive Waste Management and Environmental Remediation, Vol. 2, pp. 1225–1228.
Halbe, D., Troutman, L., Neville, R.G., Hart, L., and Ommen, R., 1979, “Destruction of cyanide in Homestake gold mill effluent — a status report,” AIME fall meeting presentation.
Hassan, S.Q., Vitello, M.P., Kupferle M.J., and Grosse, D.W., 1991, “Treatment technology evaluation for aqueous metal and cyanide bearing hazardous wastes,” Journal of the Air & Waste Management Association, Vol. 41, No. 5, pp. 710–715.
Hofseth, C.S., and Chapman, T.W., 1999, “Electrochemical destruction of dilute cyanide by copper-catalyzed oxidation in a flow-through porous electrode,” Journal of Electrochemical Society, Vol. 146, No. 1, pp. 199–207.
Hollow, J.T., Lin, H.K., Walsh, D.E., and White, D.M., 2007, “The development of an energy balance model to predict the economic impact of installing a tailings wash thickener at the Fort Knox Mine, Fairbanks, Alaska,” Minerals & Metallurgical Processing, Vol. 24, No. 2, pp. 81–96.
Kim, B.R., Podsiadlik, D.H., Kalis, E.M., Hartlund J.L., and Gaines, W.A., 1998, “Photochemical destruction of cyanide in landfill leachate,” Journal of Environmental Engineering, Vol. 124, No. 11, pp. 1108–1112.
Lien, R.H., Dinsdale, B.E., Gardner K.R., and Altnnger, P.B., 1990, “Chemical and biological cyanide destruction and selenium removal from precious metals tailings pond water,” EPD Congress 90, TMS, pp. 323–339.
Mosher, J.B., and Figueroa, L., 1996, “Biological oxidation of cyanide: A viable treatment option for the minerals processing industry?” Minerals Engineering, Vol. 9, No.5, pp. 573–581.
Oleson, J.L., 2003, “Investigation and development of a mathematical model for the oxidation of cyanide in the INCO SO2/O2 Process,” M.S. Thesis, University of Alaska Fairbanks.
Oleson, J.L., Lin, H.K., and Walsh, D.E., 2005, “Modeling of SO2/air cyanide destruction process,” Minerals & Metallurgical Processing, Vol. 22, No. 4, pp. 199–204.
Osseo-Asare, K., Xue, T., and Ciminelli, S.T., 1984, “Solution chemistry of cyanide leaching system,” Precious Metals: Mining, Extraction, and Processing, V Kudryk, D.A., Corrigan and W. W. Liang, eds., The Metallurgical Society, pp.173–197.
Poling, G.W., Ellis, D.V., Murray, J.W., Parsons, T.R., and Pelletier, C.A., 2002, Underwater Tailing Placement at Island Copper Mine, Society for Mining, Metallurgy, and Exploration, Inc., Littleton, Colorado, Chap. 8.
Ritcey, G.M., 1989, Tailing Management: Problems and Solutions in the Mining Industry, Elsevier Science Publisher, Amsterdam, The Netherlands, Chap. 12.
Riveros, P.A., Molnar, R., and Basa, F., 1996, “Treatment of a high-cyanide waste solution for cyanide and metal recovery,” CIM Bulletin, Vol. 89, No. 998, pp. 153–156.
Robbins, GH., 1996, “Historical development of the lncoSO2/air cyanide destruction process,” CIM Bulletin, Vol. 89, No. 1003, pp. 63–69.
Smith, A., 1988, “Cyanide degradation and detoxification in a heap leach,” in Introduction to Evaluation, Design and Operation of Precious Metal Heap Leaching Projects, van Zyl, Hutchison and Kiel, eds., SME, pp. 293–305.
U.S. Environmental Protection Agency, 1977, “Proposed Revisions to Ocean Dumping Criteria,” Final Environmental Impact Statement, 201 pp.
Weast, R.C., ed., 1980, CRC Handbook of Chemistry and Physics, 61st Edition, CRC Press, Inc., Boca Raton, Florida, p. D–79.
Wedl, D.J., and Fulk, R.J., 1991, “Cyanide destruction in plating sludges by hot alkaline chlorination,” Metal Finishing, Vol. 89, No. 11, pp. 33–37.
Windholz, M., ed., 1983, The Merck Index, 10th Edition, Merck & Co., Inc., Rahway, N.J., p. 696.
Young, C.A., 1998, “Mechanism of the photocatalytic destruction of cyanide species,” EPD Congress, TMS, pp. 877–886.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Lin, H.K., Walsh, D.E., Oleson, J.L. et al. Reduction of cyanate to cyanide in cyanidation tailings under reducing environments. Mining, Metallurgy & Exploration 25, 41–45 (2008). https://doi.org/10.1007/BF03403384
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/BF03403384