[Thermoacidophilic micirobial community oxidizing the gold ...

[Thermoacidophilic micirobial community oxidizing the gold-bearing flotation concentrate of a pyrite-arsenopyrite ore]. [Article in Russian] Paniushkina AE, Tsaplina IA, Grigor'eva NV, Kondrat'eva TF. ... it had lower rates of iron leaching and oxidation, while its rate of sulfur oxidation was higher. A new thermophilic acidophilic microbial ...

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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 acid and biological leaching of pyrite and arsenopyrite ...

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(PDF) Pyrite−Arsenopyrite Galvanic Interaction and ...

David et pyrite) and CPE-arsenopyrite mineral (content of 86.95% al.17 found that pyrite oxidation proceeds via a complex sequence arsenopyrite, 11.84% pyrite) has been performed in 0.1 M of series and parallel reaction steps which can be proposed from NaNO3 at pH 6.5 (adjusting with HNO3 or NaOH), as the electrochemical data and supported by ...

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Arsenic Pyrite Gold Extraction by Alkaline Leaching Oxidation

The arsenopyrite and pyrite are oxidized by an alkaline oxidative leach, and the precious metals are extracted by cyanidation of the leach residue. The alkaline leach solution is purified by precipitating arsenate and sulfate in successive steps and is recycled to the oxidative leach.

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Arsenopyrite and pyrite bioleaching: Evidence from XPS ...

The flotation concentrate was a mixture of pyrite (FeS(2)) and arsenopyrite (FeAsS); after bioleaching, 95% of the initial content of pyrite and 85% of arsenopyrite were dissolved.

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ALTA Gold 2012 E-Doc - Home | Albion Process

leaching circuits, even when the ore is finely ground. The cause of low gold recoveries can be either ... solution within sulphide minerals pyrite and arsenopyrite (FeAsS). The arsenic bearing pyrite is commonly known as arsenian pyrite and can contain gold in its structure. Rimming of pyrite with

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[Investigation of stages of chemical leaching and ...

We examined the chemical leaching and biooxidation stages in a two-stage biooxidation process of an auriferous sulfide concentrate containing pyrrhotite, arsenopyrite and pyrite. Chemical leaching of the concentrate (slurry density at 200 g/L) by ferric sulfate biosolvent (initial concentration at 3 …

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Kinetics and mechanism of arsenopyrite leaching in nitric ...

Abstract The main sulphide minerals that serve as gold carriers in low-grade raw materials are pyrite and arsenopyrite. Traditional methods of processing such refractory raw materials rely on high-pressure or pyrometallurgical oxidisation, which destroys the crystal lattice of sulphides and releases gold particles. An alternative method of oxidation is leaching with nitric acid.

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The ferric leaching kinetics of arsenopyrite - ScienceDirect

However, recent research has shown that the ferric leaching kinetics of pyrite 6, 7 and arsenopyrite may be dependent on the ferric–ferrous iron ratio (i.e., redox potential), and not a function of the total or ferric iron concentrations.

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(PDF) Arsenopyrite and pyrite bioleaching: evidence from ...

Arsenopyrite and pyrite bioleaching: evidence from XPS, XRD and ICP techniques. Analytical and bioanalytical chemistry, 2011. Bernhard Elsener. Giovanni Loi. Giovanni Rossi. ... Laboratory-scale continuous bio-oxidation of a gold concentrate of high pyrite and enargite content.

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EP0119685A1 - Hydrometallurgical arsenopyrite process ...

A process for the hydrometallurgical recovery of gold from arsenical pyrite concentrate. The process comprises decomposing the concentrate by using a leach composed of higher valence nitrogen oxides present in acidic solution; subjecting the decomposed product to a solid-liquid separation to produce a residue and a liquid fraction; recovering gold from the residue by conventional means; and ...

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Leaching of pyrite-arsenopyrite concentrate in bioreactors ...

A community of thermoacidophilic chemolithotrophic microorganisms was shown to exhibit enhanced efficiency of leaching and biooxidation of the gold-bearing pyrite-arsenopyrite flotation concentrate in continuous mode of cultivation. Under the optimal values of growth parameters, the degree of oxidation of sulfide arsenic, iron, sulfur, and antimony in the line of three laboratory reactors (D ...

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Catalytic effect of pyrite on the leaching of arsenopyrite ...

The pyrite-promoted arsenopyrite leaching in sulfuric acid was attributed to the galvanic interaction and the control of pH and redox potential, which led to the depressed formation of well-crystallized ferric arsenate (scorodite). But while leaching in iron-free 9K medium, the catalytic effect of pyrite on arsenopyrite oxidation was only ...

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(PDF) The Biological Leaching of an Auriferous Pyrite Ore ...

Pyrite and arsenopyrite do not directly pyrite and ferrous iron at pHualues as low as react.with cyanide, but may physically maskthe contact of cyanide solution witir pH 0 .6. The recoztery of gold was aaiable in colloidal-size gold disseminåted in the matrix.

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Catalytic effect of pyrite on the leaching of arsenopyrite ...

In this study, the influence of pyrite on the leaching of arsenopyrite in sulfuric acid and iron-free 9K medium was investigated by leaching experiments and electrochemical analysis.

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Arsenopyrite Gold Recovery - Mineral Processing & …

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Separating arsenopyrite from pyrite - Laboratory Testing ...

I require a high arsenopyrite concentrate with as little pyrite in it as possible for some leaching testwork but have not had any luck. Does anybody have any experience with this? I have tried using several reagents like hydrogen peroxide to float the pyrite out of the bulk concentrate, but the remaining concentrate has a low grade.

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Arsenic stability in arsenopyrite-rich cemented paste ...

Leaching of the samples was conducted with 50 ... Arsenic behaviour is different in the reference tailings sample, and is mainly controlled by arsenopyrite or arsenical pyrite oxidation at neutral pH . Thus, As compounds that control As solubility are not the same in the case of uncemented tailings and CPB samples.

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Arsenopyrite Weathering and Leaching of Arsenic in an ...

Finally, arsenic concentration was determined by ICP-MS. 2.4 Leaching Experiment of Pulverized Minerals A leaching experiment was carried out on the pure and mixed minerals to investigate the influence of the co-existence of pyrite (PY) and chalcopyrite (CP) with arsenopyrite (AP) on arsenopyrite weathering.

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OXIDATION OF PYRITE AND ARSENOPYRITE IN SULPHIDIC …

the preferential oxidation of arsenopyrite. Flotation products containing pyrite and arsenopyrite were subjected to bacterial leaching tests at 3% w/v pulp density and the degrees of oxidation were calculated and compared to with previous experimental studies.

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An XPS and XANES Study on the Bioleaching of Arsenopyrite ...

In the present study, we investigated the bioleaching of arsenopyrite with or without pyrite by moderate thermophiles. In both chemical leaching and bioleaching, the addition of pyrite decreased the leaching rate of arsenopyrite. The arsenic speciation and minerology changes in the residues were analysed by X-ray Absorption Near Edge Structure (XANES) Spectroscopy, X-ray Photoelectron ...

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Enhanced Leaching of Arsenopyrite Concentrates as a ...

Enhanced Leaching of Arsenopyrite Concentrates as a Pretreatment for Gold Recovery from Refractory Ores Published on April 20, 2017 April 20, 2017 • 6 Likes • 0 Comments

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Pressure Oxidation of a Refractory Sulfide Concentrate and ...

Oxidation of Pyrite and Arsenopyrite Oxidation of pyrite has been the subject of numerous studies which have been summarized in two comprehensive reviews (Hiskey and Schlitt, 1982, Lowson, 1982). Basic studies involving pressure oxidation of pyrite, particularly under the conditions applicable to autoclave leaching of gold-sulfide ores have ...

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[Optimization of bioleaching and oxidation of gold-bearing ...

Biooxidation of refractory gold-bearing pyrite-arsenopyrite flotation concentrate was optimized and aburidance of predominant groups in the community ofthermophilic acidophilic chemolithotrophic microorganisms at various stages ofbioleaching was determined. The optimal parameters for growth and leaching/oxidation of the mineral components of ...

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Kinetics and mechanism of arsenopyrite leaching in nitric ...

The effect of arsenopyrite on pyrite oxidation during nitric acid leaching is shown in Fig. 6b. The degree of pyrite dissolution was calculated from the extracted amount of iron minus the iron dissolved during the leaching of arsenopyrite (stoichiometric ratio As:Fe = 1).

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(PDF) Evaluation of pretreatments to increase gold ...

For gold encapsulated in arsenopyrite or pyrite, pretreatments are necessary in order to break or alter the matrix of the sulfide (Chryssoulis and McMullen, 2005;Climo et al., 2000;Hashemzadehfini ...

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Pyrite Flotation Efficiency

Leaching of the arsenopyrite/pyrite flotation concentrates ... all copper bearing minerals and majority of pyrite is collected and forwarded to a cleaner circuit. The combined concentrate flows to a conditioning tank, where lime is added for pyrite depression at pH 12.

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Arsenopyrite and pyrite bioleaching: evidence from XPS ...

12%The flotation concentrate was a mixture of pyrite (FeS 2) and arsenopyrite (FeAsS); after bioleaching, 95% of the initial content of pyrite and 85% of arsenopyrite were dissolved. The chemical state of the main elements (Fe, As and S) at the surface of the bioreactor feed particles and of the residue after bioleaching was investigated by X-ray ...

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Galvanic interaction of grinding media with arsenopyrite ...

Galvanic interactions between different types of grinding media and arsenopyrite and pyrite, during the grinding was quantified and the effect of galvanic interactions on gold cyanide leaching was investigated. The synthetic ores were prepared by mixing arsenopyrite or pyrite with clean gravity gold concentrate and quartz.

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arsenopyrite pyrite leaching - samariter-rubigen.ch

Chemical leaching of the concentrate (slurry density at 200 g/L) by ferric sulfate biosolvent (initial concentration at 3 … We examined the chemical leaching and biooxidation stages in a two-stage biooxidation process of an auriferous sulfide concentrate containing pyrrhotite, arsenopyrite and pyrite.

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