Abstract
The direct recovery of precious metals from alkaline cyanide solution is frequently accomplished by the well-established Merrill-Crowe process involving zinc-dust cementation. This is particularly true for silver. Plant data from two operations are presented and analyzed in terms of intrinsic reaction features. In such Merrill-Crowe plants a plate-and-frame filter press acts as a semicontinuous fixed-bed reactor with a distribution of particle retention times. For the plants studied, 99% of the silver is recovered with a solution retention time of less than 2 min. Differences in plant operating conditions and product characteristics can be related to the nature of the surface deposit of silver which forms on the zinc particles. From laboratory experiments and plant samples it has been found that the presence of lead in the system activates a change in the silver deposit morphology to the dendritic state which affects the rate of silver deposition as well as the filter cake porosity. Finally the plate-and-frame press is considered from an engineering perspective as a semi-continuous fixed-bed reactor to describe the behavior of the system.
Similar content being viewed by others
References
Hines, A.L., and Maddix, R.N., 1985, Mass Transfer Fundamentals and Applications, Prentice-Hall, Inc., Englewood Cliffs, NJ, p. 195.
Leblanc, R., 1942, “Precipitation of Gold from Cyanide Solution by Zinc Dust,” Canadian Mining Journal, April, May, June, pp. 213–219, 297–306, 371–379.
Miller, J.D., 1981, “Solution Concentration and Purification,” Metallurgical Treatises, J.R. Tien and J.F. Elliott, eds., AIME, New York, pp. 95–116.
Parga, J.R., 1987, “Analysis of the Zinc Cementation Reaction for Recovery of Precious Metals from Cyanide Solutions,” Ph.D. Dissertation, Dept. of Metallurgy and Metallurgical Engineering, University of Utah, Salt Lake City, April.
Parga, J.R., Wan, R.Y., and Miller, J.D., 1987, “Intrinsic Reaction Kinetic Features in Zinc-Dust Cementation of Precious Metals from Alkaline Cyanide Solution,” SME Annual Meeting, Denver, CO, March.
Ritchie, I.M., and Staunton, W.P., 1984, “Electrochemical Investigations and Electron Microscopy of Silver (I)-Copper Cementation Reaction,” Proceedings, International Symposium on Electrochemistry in Mineral and Metal Processing, P.E. Richardson, S. Srinivasan, and R. Woods, eds., The Electrochemical Society, Pennington, NJ, pp. 486–500.
Strickland, P.H., and Lawson, F., 1971, “The Cementation of Metals from Dilute Aqueous Solutions,” Proceedings, Australasian Institute of Mining & Metallurgy, Melbourne, No. 237, pp. 71–78.
Von Hahn, E.A., and Ingraham, T.R., 1968, “Kinetics of Silver Cementation on Zinc in Alkaline Cyanide Solutions and Perchloric Acid Solutions,” Canadian Metallurgical Quarterly, Vol. 7, pp. 15–26.
Wadsworth, M.E., 1986, “Precipitation Reactions in Hydrometallurgical Systems,” Advances in Mineral Processing, P. Somasundaran, ed., Society of Mining Engineers, Inc., Littleton, CO, pp. 487–492.
Author information
Authors and Affiliations
Additional information
M&MP paper 87–641. Discussion of this paper must be submitted, in duplicate, prior to Oct. 31, 1988.
Rights and permissions
About this article
Cite this article
Parga, J.R., Wan, R.Y. & Miller, J.D. Zinc-dust cementation of silver from alkaline cyanide solutions — analysis of Merrill-Crowe plant data. Mining, Metallurgy & Exploration 5, 170–176 (1988). https://doi.org/10.1007/BF03402506
Received:
Published:
Issue Date:
DOI: https://doi.org/10.1007/BF03402506