Cyanide recovery from a gold mill barren solution containing high levels of copper.

The recovery of cyanide from a gold mill solution containing high levels of copper (400 mg/L to 900 mg/L) using the AVR process was evaluated. It was determined that acidification to pH 2 to 3 provides a suitable balance between HCN generation, copper precipitation and acid consumption. A short pilot plant campaign showed that ~75% of the feed WAD cyanide was recovered while the remainder precipitated along with copper upon acidification. The acid consumption averaged 3.5 g H2SO4 per litre of solution. The copper precipitate, consisting mostly of CuCN and CuSCN, was readily separated from the solution by gravity. The volatilization of HCN in countercurrent packed columns averaged 98.7% efficiency. Reabsorption of HCN was practically 100% in NaOH solutions and slightly lower in a lime slurry. Basic volatilizer design parameters applicable to a large-scale operation were determined, including the HenryÕs Law constant and the mass transfer coefficient of HCN gas.
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Summary: The gemological properties that allow natural emeralds and blue sapphires to be distinguished from other gemstones are summarized int this paper. A variety of synthetic and laboratory-treated emeralds and blue sapphires are also encountered in the jewelry industry today. Gemologists distinguish these latter materials from their natural counterparts based primarily upon features seen with magnification, such as inclusions and/or growth zoning. In some cases, however, these observations and...
Publication: CIM Bulletin
Author(s): J.E. Shigley
Issue: 1025
Volume: 91
Year: 1998
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Summary: LÕanalyse des sŽquences dÕexploitation, actuellement en usage pour les gisements tr?s inclinŽs, a dŽmontrŽ quÕelles ne sont pas toujours optimales du point de vue du contr™le des terrains et de la concentration des travaux dÕabattage (nombre de chantiers simultanŽment en opŽration). Effectivement plusieurs sŽquences sont tr?s propices ˆ la crŽation des nombreuses zones de hautes contraintes, qui sont ˆ lÕorigine des effets de pilier. LÕŽtude de cas de la mine Lac Shortt a dŽmontrŽ que...
Publication: CIM Bulletin
Author(s): S. Planeta, J. Szymanski, A. Coulombe
Issue: 1025
Volume: 91
Year: 1998
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Summary: In this paper, the author offers a personal view of what the next 30 years holds for mineral processing. Restating that mineral processing will remain a vibrant industry in raw material production, growth opportunities in waste management are identified. The processing sequence familiar now (mining ® mineral processing ® extraction) will become more interwoven. In situ processing (i.e., milling underground) will evolve from concept to demonstration. Opportunities to exploit physical propertie...
Publication: CIM Bulletin
Author(s): J.A. Finch
Issue: 1025
Volume: 91
Year: 1998
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