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bacterial leaching gold ores
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Two-stage microbial leaching of a refractory gold-bearing …
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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Microbial leaching of metals from sulfide minerals
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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(PDF) Microbial leaching of gold from ores
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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Gold Dissolution from Ore with Iodide-Oxidising …
Gold leaching from ore using iodide-iodine mixtures is an alternative to gold cyanidation. This study evaluated the ability of iodide …
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Bacterial Leaching of Minerals | SpringerLink
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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Gold Ore Using Iodide-Oxidizing Bacteria
bacterial cell number had no e ect on gold dissolution when it was 1 104 cells/mL or higher. Gold leaching with IOB should be operated under a temperature range of 30–35 C, which was the optimal temperature range for IOB. The bacterial growth rate under shaking conditions was three times faster than that under static conditions.
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Bacteria Leaching of Gold Encapsulated in Pyrite
Bacteria Leaching of Gold Encapsulated in Pyrite. It is known that many of the gold and silver deposits are often associated with sulfide minerals, specially pyrite. Some of the precious metals in such ores are often found as very finely disseminated particles inside the sulfide crystals. The encapsulation of the precious metals particles in ...
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Bioleaching of Gold from Sulfidic Gold Ore Concentrate and …
As a result, the impact of bacterial species or leaching method (excluding uninoculated ore control) on gold leaching from ore concentrate was not significant for day 10, although p-values indicated significant impact in …
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Microbial oxidation of gold ores and gold bioleaching
Gold extraction in- creased from 5% in the untreated concentrate to over 90% after bio-oxidation. Heap leaching. When fine grinding of large amounts of low grade gold ores is uneconomical, microbial oxidation of refractory gold ores in …
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Research status of carbonaceous matter in carbonaceous gold ores …
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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Gold Dissolution from Ore with Iodide-Oxidising Bacteria
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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Consideration of Influential Factors on Bioleaching of Gold …
The initial bacterial cell number had no effect on gold dissolution when it was 1 × 104 cells/mL or higher. Gold leaching with IOB should be operated under a temperature range of 30–35 °C, which was the optimal temperature range for IOB. The bacterial growth rate under shaking conditions was three times faster than that under …
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Biomining: Metal Recovery from Ores with Microorganisms
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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Microbial oxidation of gold ores and gold bioleaching
Much recent work in the field of biohydrometallurgy has been directed to the study of bio-oxidation of gold ores by acidophilic iron and sulfur oxidizing microorganisms. This work has been done worldwide and has resulted in several pilot plant and commercial scale operations for gold ore bio-oxidation. Bioleaching of gold by metabolic products ...
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Gold leaching from ores using biogenic lixiviants – A review
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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Alternative Lixiviants to Cyanide for Leaching Gold Ores
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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Microbial oxidation of gold ores and gold bioleaching
Much recent work in the field of biohydrometallurgy has been directed to the study of bio-oxidation of gold ores by acidophilic iron and sulfur oxidizing microorganisms. This work has been done worldwide and has resulted in several pilot plant and commercial scale operations for gold ore bio-oxidation. Bioleaching of gold by metabolic products of …
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Improving gold recovery from refractory gold ores
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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(PDF) Refractory gold-bearing ores: a review of treatment …
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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Progress in bioleaching: fundamentals and mechanisms of …
For gold and silver recovery from refractory ores, the activity of leaching microorganisms is applied only to dissolve metal sulfides like arsenopyrite bearing the …
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Minerals | Free Full-Text | Hydrometallurgical Processing of Low …
The authors describe the opportunities of low-grade sulfide ores and mine waste processing with heap and bacterial leaching methods. By the example of gold and silver ores, we analyzed specific issues and processing technologies for heap leaching intensification in severe climatic conditions. The paper presents perspectives for heap …
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Likely scenarios in the microbial leaching of gold from …
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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Bacterial Leaching
Bacterial leaching is the extraction of metals from their ores using microorganisms. Microbial technology offers an eco ... oxidation of gold ores is a less costly, less polluting alternative to other oxidative pretreatments such as roasting and pressure oxidation. GENERAL I ARTICLE copper-leaching operations. Acidithiobacillus ferrooxidans ...
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A systematic review of sustainable gold extraction from raw ores …
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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Gold Dissolution from Ore with Iodide-Oxidising Bacteria
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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Possibilities for the Environmental Processing of Gold-Bearing Ores …
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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Flotation of gold and gold-bearing ores
Flotation reagents at the Stawell Gold Mine in Victoria, Australia, where carbonaceous pyrite–pyrrhotite gold ores with minor quantities of arsenopyrite are floated at a slightly elevated pH value, include copper sulfate, PAX and Terric 407 frother. The concentrate is reground before cyanide leaching. 10.5. Copper–gold ores
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Bioleaching: A microbial process of metal recovery; A …
The Bacterial Oxidation (BIOX) process for the pre-treatment of refractory ores for gold recovery developed by Genmin, the mining division of Gencor, has been operating successfully at the ...
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Comparison of three different bioleaching systems for Li
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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Bioleaching of Gold from Sulfidic Gold Ore Concentrate and …
Gold bioleaching mediated by iodide oxidizing bacteria (IOB) has been proposed as a sustainable alternative to conventional technologies such as cyanidation. …
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Mineralogical characteristics and treatment of refractory gold ores
Keywords Refractory gold ores; oxidation roasting; aqueous pressure oxidation; bacterial leaching; gold economics; environmental considerations. INTRODUCTION Refractory gold ores and concentrates are characterised by low gold recoveries and high cyanide consumptions when subjected to direct cyanide leaching …
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Progress, Challenges, and Perspectives of Bioleaching for
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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Heavy Metal Pollution from Gold Mines: Environmental …
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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Pretreatment Process on Refractory Gold Ores with As
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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Microbial Leaching (Bioleaching, Biomining)
In direct bacterial leaching a physical contact exists between bacteria and ores and oxidation of minerals takes place through several enzymatically catalyzed steps. For example, pyrite is oxidized to ferric sulphate as …
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Likely scenarios in the microbial leaching of gold from …
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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Microbial oxidation of gold ores and gold bioleaching | FEMS
Much recent work in the field of biohydrometallurgy has been directed to the study of bio-oxidation of gold ores by acidophilic iron and sulfur oxidizing …
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Bacterial Oxidation of Refractory Sulfide Ores for Gold …
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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Effect of antimonate on the bacterial oxidation of sulfide …
The processing of persistent gold-bearing ores includes collective flotation of the sulfide minerals in the ore, bacterial oxidation of the concentrates, and cyanation of the cakes obtained by leaching. During bacterial oxidation, the sulfides dissolve and the gold in them is opened up and becomes accessible for cyanation.