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Microbial leaching of gold from ores. April 1988; Conference: Symposium on Precious and Rare Metals, 1988 ... Different heterotrophic bacteria leached gold from two gold-bearing silicate ores and ...
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The Roseovarius tolerans was used in another attempt to dissolve gold from the same high-grade gold ore (Au: 0.26 wt%) that was used in the study mentioned above (Khaing et al., 2019a).The initial concentration of bacterial cells, concentrations of nutrient (marine broth) and potassium iodide, the incubation temperature, and shaking versus …
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Numerous studies have demonstrated the presence of bacteria attached to the ores and/or present in the pregnant leach solutions (PLS) in commercial operations. Sand et al. (1995) proposed a typical model for the bacterial leaching, which essentially proceeds by ferric ions complexation by the secreted extra cellular polymeric substances …
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Abstract. A pyrite ore containing 3.2 g/ton of gold finely disseminated in the sulphide matrix was leached to recover this precious metal. The leaching was carried out in columns containing 200 kg of ore crushed to minus 10 mm. The ore was initially leached by solutions containing chemolithotrophic bacteria, ferric ions, dissolved oxygen and ...
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Bacterial leaching is presented as an environmentally and economically alternative technology for the mineral industry. Keywords. ... G.N. (1988) Microbial leaching of refractory gold ores. Australian Mining, (October) p. 48–57. Google Scholar Carranza, F. (1990). Selective cyclic bioleaching of a copper-zinc sulphide concentrate. ...
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The use of bacteria in gold extraction, known as biomining, has received considerable attention due to the potential roles played by these bacteria in the recovery of gold from gold-bearing ores. ... These bacteria help in solubilizing the sulphide matrix of the gold deposits thereby making the gold more reachable to leaching by the chemical ...
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Microbial ore leaching (bioleaching) is the process of extracting metals from ores with the use of microorganisms. This method is used to recover many different precious metals like copper, lead, zinc, …
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Groudev et al. (1999) used solutions that contained amino acids of microbial origin and thiosulphate to leach the gold and silver from oxide ores that contained 3.5 g/t of gold and 14 g/t of silver. First, an alkaline solution (pH 10–10.5) was irrigated on the top …
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Gold leaching from ore using iodide-iodine mixtures is an alternative to gold cyanidation. This study evaluated the ability of iodide-oxidising bacteria to solubilise gold from ore that was mainly composed of gold, pyrite, galena, and chalcopyrite. Eight bacterial strains were successfully isolated from brine.
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It can dramatically improve gold cyanide leaching rate. Roasting has advantages of mature and reliable technology, simple operation, adaptability, etc.But it is easy to form secondary wrapping to reduce leaching rate of gold in the roasting process, and at the same time produces gases of SO 2 and As 2 O 3 polluting environment seriously. In ores with a …
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Bacterial assisted leaching processes are based on the ability of certain microorganisms to solubilize/or expose the metals contained in the ores and concentrates by direct oxidation, or through ...
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Principally, in order to achieve high gold recovery from refractory ores, ore pre-treatment is required prior to cyanidation leaching. The application of bacterial oxidation (biooxidation) for pre-treatment of refractory sulfide gold concentrates is now considered as a proven commercial technique.
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In comparison to copper leaching and the biooxidation of refractory gold ores and concentrates, bioleaching of other metals, for example, nickel, cobalt, and zinc, is still an exception. ... (2008) Bacterial leaching of nickel laterites using chemoautotrophic microorganisms: identifying influential factors using statistical design of ...
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The bacteria release gold from the ores during the oxidation of sulfur or iron from sulfide ores. ... Aylmore, M.G. Alternative lixiviants to cyanide for leaching gold ores. In Gold Ore Processing; Elsevier: Amsterdam, The Netherlands, 2016; pp. 447–484. [Google Scholar] Fisher, L. Hydrothermal Processes at the Osborne Fe-Oxide-Cu-Au …
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At the São Bento plant, gold and pyrite are floated into a bulk concentrate for further processing by pressure and bacterial leaching (the latter is currently on care and maintenance). ... PAX, and Terric 407 frother. The concentrate was reground before cyanide leaching. 10.5. Copper–Gold Ores. Copper–gold ores are significant …
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The gold leaching rate of carbon-bearing high-arsenic refractory gold concentrate of Guangdong province is only 15.02%. YANG et al [52] employed HYK 2 flora to treat this refractory gold ores, and the bacteria could excrete a mass of organic substances when the metal sulfides were oxidized.
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Bio-leaching is a cost effective, efficient, safe, and. environmentally friendly way to treat refractory gold concentrates and ores. Compared. to roasting, bio-leaching can generally reduce ...
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Semantic Scholar extracted view of "Bacterial heap leaching of refractory gold/sulphide ores" by D. Holtum et al. Skip to search form Skip to main content ... @article{Holtum1994BacterialHL, title={Bacterial heap leaching of refractory gold/sulphide ores}, author={D. A. Holtum and D. M. Murray}, journal={Minerals Engineering}, …
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Abstract. The microbiological leaching of refractory sulfide ores (pyrite, arsenopyrite) for recovery of gold is reviewed in this article. The underlying physiological, biochemical, and genetic fundamentals of the bacteria involved (Thiobacillus and Sulfolobus spp.) are complex and have yet to be elucidated in depth.The chemistry of …
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Precious metals are often lost in tailings owing to encapsulation of the precious metal particles in the ores. To solve this problem, tailing samples are pretreated by biological leaching before cyanide leaching, which has increased the leaching rate of gold to 95% and the leaching rate of silver to over 98% . However, cyanide is toxic and ...
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Diagnostic leaching results showed 39.7 wt% of total gold was leachable using direct cyanide leaching, and around 33 wt% of undissolved gold was located in pyrite and arsenopyrite. View Show abstract
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Gold leaching from ore using iodide-iodine mixtures is an alternative to gold cyanidation. This study evaluated the ability of iodide-oxidising bacteria to …
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The impact of bacterial species on triiodide concentration during gold leaching from ore concentrate was significant for days 1 and 5, but not on day 10, …
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Microorganisms are important in metal recovery from ores, particularly sulfide ores. Copper, zinc, gold, etc. can be recovered from sulfide ores by microbial leaching. Mineral solubilization is achieved both by 'direct (contact) leaching' by bacteria and by 'indirect leaching' by ferric iron (Fe 3+) that is regenerated from ferrous iron ...
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Uranium can be successfully recovered by flooding the fractured ores containing uranium with the bacterial community causing the leaching process. Bioleaching of uranium from low grade uranite ore is generally carried out by heap bioleaching (Vázquez-Campos et al. 2017). Uranium is extracted from uraninite as:
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Two pure cultures of cyanogenic bacteria, i.e., P. aeruginosa and B. megaterium, were used for the bioleaching of an oxidized copper–gold ore (6.2 g Au/ton …
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Roasting of complex gold ores, namely sulphides and carbonaceous (refractory gold ores), should take place before leaching in order to maximise the extraction ratio (Neuvonen, 2013). It should feature in cases where, even following long grinding processes, the exposure of gold to the leaching solution has been minimal (it, …
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Because of the similar stabilities of gold and silver bisulfide complexes, bisulfide leaching may be suitable for leaching gold ores with significant silver content (Hunter et al., 1998). The YES process uses naturally occurring, sulfate-reducing bacteria for the recovery of gold and silver from ores.
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Block diagram of the bacterial leaching process. 1.3.4 Bioleaching An alternative to the aforementioned methods can be found in bacterial leaching (Fig. 4), a biological process whereby the leaching of sulphide min- erals is catalyzed by microorganisms. 2.
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The X-ray diffraction analysis for bioleaching residue indicated changes caused by microorganisms, however, with differences between bacterial leaching and bioleaching by fungi or yeasts.
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