Investigation of the Effective Parameters on the Cyanide Fate in Soil

Document Type : Research Paper


1 Graduate Student of Environmental Engineering, Department of Civil Engineering, Isfahan University of Technology

2 Associate Professor, Department of Civil Engineering, Isfahan University of Technology

3 Associate Professor, College of Agriculture, Isfahan University of Technology


Natural degradation of cyanide is one of the oldest methods used to remove the cyanide present in industrial wastewater of electroplating and extraction processes in gold and silver industries. The most important mechanism involved in the natural degradation of cyanide is volatilization which is affected by parameters such as impoundment surface, soil porosity and density, initial concentration, and atmospheric conditions. The objective of the present study was to determine the effects of those parameters involved in natural degradation that can be varied to optimize the design or operation of tailings impoundment. The experiments carried out in this study were of the completely random, statistical factorial, and time-split design using the four major variables of time, surface to depth ratio, tillage operations, and soil cyanide initial concentration.  The experiments included 3 levels for surface-depth ratio, 2 levels for tillage operation, and 2 levels for initial concentration with three replications to yield a total number of 36 pilots. Cyanide measurements were performed at four intervals. Statistical analysis and variance of the data obtained on soil cyanide concentration showed that time had the highest effect on soil cyanide removal. Tillage and increased initial contamination both increased cyanide removal efficiency. For a given volume of cyanide contaminated soil, increased surface-depth ratio led to a faster reduction of soil cyanide residual. The regression analysis of the data obtained from this study resulted in the development of a model that can be used to predict soil cyanide concentration with respect to such parameters as time, initial contamination, and surface-depth ratio.


1- Department of the Environment and Heritage, Canberra, ACT, Australia. (2003). “Cyanide management.” <> (March 10, 2004).
2- Ellis, D. (1997). “Investigation and modeling of the natural decay of cyanide in a gold mine tailings pond.” MS. thesis, University of Western Australia, Australia.
3- Knowles, C.J. (1988). Cyanide compounds in biology, section: Cyanid utilization and degradation by microorganisisms, Ciba Foundation, John Wiley and Sons Ltd., Chichester, UK, 3-9.
4- Clesceri, L.S., Greenberg, A.E., and Eaton, A.D., eds.(1998). Standard methods for the examination of water and wastewater, 20th Ed., APHA, AWWA, WEF, Washington DC.
 5- Scott, J.S. (1989). “An overview of gold mill effluent treatment. ”  Proc. The Gold Mining Effluent Treatment Seminars, Vancouver, British Columbia, Canada, 1-22.
6- Smith, A.C.S., and Mudder, T.I. (1999). The environmental geochemistry of cyanide, In G.S. Plumlee and M.J. Logsdon (Vol. eds.), Review in economic geology: Vol. 6A. The environmental geochemistry of mineral deposits: Part A. Processes, technologies, and health issues, Society of Economic Geologists, Littleton, CO, 229-248.
7- Chatwin, T.D., and Trepanowski, J.J. (1987). “Utilization of soils to migrate cyanide releases.” Proc. The 3rd Western Regional Conference on Precious Metals, Coal and Environment, C.Kliche & K.Han, eds., South Dakota School of Mines and Technology, Rapid City, South Dakota, USA, 201-211.
8- Simovic, L. (1984). “Kinetics of natural degradation of cyanide from gold mill effluents.” MS. thesis, McMaster University, Hamilton, Ontario, Canada.
9- Fuller, W.H. (1984). “Cyanides in the environment with particulate attention to the Soil.” Proc. The Conference on Cyanide and the Environment, Vol. 1, D. Van Zyl, ed., Tucson, Arizona, 19-46.
10- Botz, M.M., and Mudder, T.I. (2000). “Modeling of natural cyanide attenuation in tailings impoundments.” Minerals and Metallurgical Processing, 17, 228-233.
11- Mehling, P., and Broughton, L. (1989). “Fate of cyanide in abandoned tailings ponds.”
Proc. The International Symposium on Tailings and Effluent Management, M.E. Chalkley, B. R. Conard, V. I. Lakshmanan, & K. G. Wheeland, eds., Halifax, Canada, 269-279.
12- Simovic, L., and Snodgrass, W.J. (1989). “Tailings pond design for cyanide control at gold mills using natural degradation.” Proc. The Gold Mining Effluent Treatment Seminars, Vancouver, British Columbia, Canada, 57-81.
13- Simovic, L., Snodgrass, W.J., Murphy, K.L., and  Schmidt J.W. (1984). “Development of a model to describe the natural degradation of cyanide in gold mill effluents.” Proc. The Conference on Cyanide and the Environment, Vol. 2, D. Van Zyl, ed., Tucson, Arizona, 413-432.
14- تائبی، ا.، زاده بافقی، ع. ر.، و سرتاج، م. (1384). ” انتقال و زوال طبیعی سیانور در خاک: مطالعه موردی دشت موته. “ م. آب و فاضلاب، 56، 21-29.