Mobilization of Silver, Gold, and Platinum from Solid Materials by HCN-Forming Microorganisms

Helmut Brandl; Stefan Lehmann; Mohammad A. Faramarzi

doi:10.4028/www.scientific.net/AMR.20-21.50

Paper Titles

Comparison of the Bioleaching Effect of Mesophilic (35°C) and Thermophilic (45°C) Bacteria on the TIZAPA Tailings
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Application Potential of Biohydrometallurgy in the Iranian Mining Industry
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The Bioshale Project: Search for a Sustainable Way of Exploiting Black Shale Ores Using Biotechnology
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Removal of Organically Bound Sulfur From Oil Shale by Iron(III)-Ion Generated-Regenerated from Pyrite by the Action of Acidithiobacillus ferrooxidans
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Mobilization of Silver, Gold, and Platinum from Solid Materials by HCN-Forming Microorganisms
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High-Rate Fluidized-Bed Ferric Sulfate Generation for Hydrometallurgical Applications
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Development of a Tank Bioleaching Process for the Treatment of Complex Cu-Polymetallic Concentrates
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Continuous Bioleaching of a Cobaltiferous Pyrite in Stirred Reactors: Population Dynamics and EPS Production vs. Bioleaching Performances
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Characterisation of Factors in the Bacterial Leaching of Nickel Laterites Using Statistical Design of Experiments
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HomeAdvanced Materials ResearchAdvanced Materials Research Vols. 20-21Mobilization of Silver, Gold, and Platinum from...

Mobilization of Silver, Gold, and Platinum from Solid Materials by HCN-Forming Microorganisms

Abstract:

Cyanogenic Chromobacterium violaceum, Pseudomonas fluorescens, and P. plecoglossicida were able to mobilize silver, gold and platinum when grown in the presence of various metal-containing solids such as powdered platinum, platinum-containing automobile catalytic converters, powdered silver, or gold-containing electronic scrap. Five percent of silver was mobilized from powdered jewelry scrap as dicyanoargentate after one day, although 96% was mobilized when non-biological cyanide leaching was applied. Dicyanoargentate proved to inhibit growth at concentrations >20 mg/L. Gold was microbially solubilized from electronic scrap (shredded printed circuit boards). Maximum dicyanoaurate concentration corresponded to a 68.5% dissolution of the total gold added. Additionally, cyanide-complexed copper was detected during treatment of electronic scrap due to its high copper content of approximately 100 g/kg scrap. Small amounts of platinum were mobilized from pure platinum powder after 10 days. The process proved to be very slow. In summary, all findings demonstrate the potential of microbial mobilization of metals as cyanide complex from solid materials and represent a novel type of microbial metal mobilization which might find industrial application.