Effect of Pretreatment of Sulfide Refractory Concentrate with Sodium Hypochlorite, Followed by Extraction of Gold by Pressure Cyanidation, on Gold Removal


The majority of the refractory gold and silver occurs in occlusion in sulphides, then precious metal dissolution is possible by first oxidizing auriferous sulfide concentrate using sodium hypochlorite-sodium-hydroxide solution followed of pressure cyanidation of the oxidized concentrate, for the extraction of precious metals. This process was conducted and evaluated under cyanide and oxygen pressure. This versatile approach offers many advantages, including low temperatures, low pressure and less costly materials of construction than conventional pressure oxidation. In this study, the effect of oxygen pressure, concentration of sodium hypochlorite, temperature, and initial pH, in precious metals recovery and As removal were evaluated using a 24 factorial design. Characterization of the ores showed that pyrite and arsenopyrite were the main minerals present on the concentrate. The best results for gold extraction were obtained with oxygen pressure of 80 psi, 10% (w/w) sodium hypochlorite, temperature of 80, at pH = 13, and a constant stirring speed of 600 rpm. These conditions allowed an approximated 60% of gold and 90% of silver extractions in 1 hr.

Share and Cite:

A. Valenzuela, J. Valenzuela and J. Parga, "Effect of Pretreatment of Sulfide Refractory Concentrate with Sodium Hypochlorite, Followed by Extraction of Gold by Pressure Cyanidation, on Gold Removal," Advances in Chemical Engineering and Science, Vol. 3 No. 3, 2013, pp. 171-177. doi: 10.4236/aces.2013.33021.

Conflicts of Interest

The authors declare no conflicts of interest.


[1] J. O. Marsden and C. I. House, “The Chemistry of Gold Extraction,” 2nd Edition, S.M.E., Littleton, 2006, pp. 147-177.
[2] J. H. Coronado, M. A. Encinas, J. C. Leyva, J. L. Valenzuela, A. Valenzuela and G. T. Munive, “Tostación de un Concentrado Refractario de oro y Plata. Revista de Metalurgia,” Espana, Vol. 48, No. 3, 2012, pp. 165-174.
[3] L. Rusanen, J. Aromaa and O. Forsen, “Pressure Oxidation of Pyrite-Arsenopyrite Refractory Gold Concentrate,” Academic Journal, Physicochemical Problems of Mineral Processing, Vol. 49, No. 1, 2013, p. 101.
[4] M. A. Márquez, J. D. Ospina and A. L. Morales, “New Insights about the Bacterial Oxidation of Arsenopyrite: A Mineralogical Scope,” Minerals Engineering, Vol. 3, 2012, pp. 248-254. doi:10.1016/j.mineng.2012.06.012
[5] M. Saba, M. A. R. Fereshteh and J. Moghaddam, “Diagnostic Pre-Treatment Procedure for Simultaneous Cyanide Leaching of Gold and Silver from a Refractory Gold/Silver Ore,” Minerals Engineering, Vol. 24, No. 15, 2011, pp. 1703-1709. doi:10.1016/j.mineng.2011.09.013
[6] G. H. Mehdi, F. R. Schreiberb and R. Shahram, “Simultaneous Sulfide Oxidation and Gold Leaching of a Refractory Gold Concentrate by Chloride-Hypochlorite Solution,” Minerals Engineering, 2012, pp. 1-3.
[7] S. A. Awe and A. Sandstrom, “Selective Leaching of Arsenic and Antimony from a Tetrahedrite Rich Complex Sulphide Concentrate Using Alkaline Sulphide Solution,” Minerals Engineering, Vol. 23, 2012, pp. 1227-1236 doi:10.1016/j.mineng.2010.08.018
[8] G. C. Jones, M. Becker, P. van H. Robert and T. L. H. Susan, “The Effect of Sulfide Concentrate Mineralogy and Texture on Reactive Oxygen Species (ROS) Generation,” Applied Geochemistry, Vol. 29, 2013, pp. 199-213. doi:10.1016/j.apgeochem.2012.11.015
[9] J. Jin, S. Shi, G. Liu, Q. Zhang and W. Cong, “Arsenopyrite Bioleaching by Acidithiobacillus ferrooxidans in a Rotatingdrum Reactor,” Minerals Engineering, Vol. 39, 2012, pp. 19-22. doi:10.1016/j.mineng.2012.07.018
[10] J. J. K. Gordon and E. K. Asiam, “Influence of Mechano-Chemical Activation on. Biooxidation of Auriferous Sulphides,” Hydrometallurgy, Vol. 115-116, 2012, pp. 77-83. doi:10.1016/j.hydromet.2011.12.014
[11] A. Hol, R. D. van der Weijden, G. Van Weert, P. Kondos and J. N. Cees, “Bio-Reduction of Elemental Sulfur to Increase the Gold Recovery from Enargite,” Hydrometallurgy, Vol. 115-116, 2012, pp. 93-97. doi:10.1016/j.hydromet.2012.01.003
[12] G. R. Zárate, G. T. Lapidus and R. D. Morales, “Aqueous Oxidation of Galena and Pyrite with Nitric Acid at Moderate Temperatures,” Hydrometallurgy, Vol. 115-116, 2012, pp. 57-63. doi:10.1016/j.hydromet.2011.12.010
[13] A. Basua and M. E. Schreiber, “Arsenic Release from Arsenopyrite Weathering: Insights from Sequential Extraction and Microscopic Studies,” Journal of Hazardous Materials, Vol. 244, 2013.

Copyright © 2023 by authors and Scientific Research Publishing Inc.

Creative Commons License

This work and the related PDF file are licensed under a Creative Commons Attribution 4.0 International License.