New Approach for Lead, Zinc and Copper Ions Elimination in Cyanidation Process to Improve the Quality of the Precipitate

José R. Parga¹, Jesús V. Valdés¹, Jesús L. Valenzuela², Gregorio Gonzalez³, L. María de J. Pérez¹, T. Francisco Cepeda¹

¹Department of Materials Science and Metallurgy, Technological Institute of Saltillo, Saltillo, México.
²Departament of Chemical Engineering and Metallurgy, University of Sonora, Hermosillo, México.
³Faculty of Metallurgy, University of Coahuila, Monclova, México.

DOI: 10.4236/msa.2015.62015                

Abstract

The Merrill-Crowe zinc-precipitation process has been applied worldwide on a large number of operations for recovering gold and silver from cyanide solutions. However, in some of the large plants this precipitate is of low quality, because copper and especially lead are precipitated along with gold and silver resulting in a higher consumption of zinc powder, fluxes in the smelting of the precipitate, formation of mate and short life for crucibles. In this research, a method is proposed to recover lead, zinc and copper cyanide ions from barren solutions, from the Merrill-Crowe process with hydroxyapatite before the filter press. This technology is based on inducing nucleated precipitation of zinc, copper and silver ions in a serpentine reactor, using sodium sulfide as the precipitator and sulfuric acid for pH control. This procedure was successfully applied at WILLIAM Mining and BACIS Mining Group in México.

Keywords

Gold-Silver Recovery, Hydroxyapatite, Merrill-Crowe, Sulphide Precipitation

Conflicts of Interest

The authors declare no conflicts of interest.

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