Strain selection for high temperature oxidation of mineral sulfides in reactors. In . Harnessing Biotechnology for the 21st Century: Proceedings of the Ninth International Biotechnology Symposium and Exposition. ... Bio-oxidation of a refractory gold bearing high arsenic sulphide concentrate: a pilot study.
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Pressure oxidation (POX) remains a further option for the oxidation of refractory sulfides. Several projects have been recently constructed: the Killita Project in Finland, the Amursk Project in Russia, the Pueblo Viejo Project in …
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Gold ores can be categorized into two types - free milling and refractory. Free milling ores are those easy to process by simple gravity techniques or direct cyanidation. ... The oxidation of sulphide minerals by T. ferrooxidans can be considered as (1) direct bacteria oxidation of the sulphide mineral and (2) indirect sulphide oxidation by Fe3 ...
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Pre-oxidation of sulfide minerals using ammonium solutions containing cupric ions can be considered as a pretreatment process for refractory gold ores at ambient temperature and pressure conditions. In this pretreatment process, sulfide minerals are oxidized by cupric ions (or cupric amine complexes), and associated metal species such as copper ...
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Chemical oxidation is a promising pretreatment method for refractory pyrite enclosure to enhance Au/Ag extraction. Here, persulfate was employed for stepwise oxidation of a refractory pyrite concentrate with encapsulated Au/Ag: (i) pyrite oxidation began with heating-activation persulfate, where hydroxyl radical (•OH) acted as the primary oxidative species for …
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The high-pressure nitric acid oxidation process is shown in Figure 1. LI, D.-X. Developments on the pretreatment of refractory gold minerals by nitric acid. World Gold Conference 2009,The Southern African Institute of Mining and Metallurgy, 2009. Developments in the pretreatment of refractory gold minerals by nitric acid D.-X. LI
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Gold resources are explored and mined widely in the world. But with the increasing depletion of free-milling gold ores, the mining and utilization of refractory gold ores have become a huge challenge for metallurgy and mineral processing (Konadu et al., 2019).At present, gold acquired from refractory gold ores has been accounted for one-third of the total gold …
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The paper presents an overview of bio-oxidation of sulphidic refractory gold ores prior to gold cyanidation. This review discusses several factors, more importantly, oxygen requirements and oxygen limitations in biological oxidation of various sulphide minerals associated with gold ores. The availability of sufficient oxygen in bio-oxidation systems can …
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Oxidation . ABSTRACT . The Leachox refractory gold process has to date been applied to the selectivetreatment of several refractory gold ores but on a relatively small scale. In this paper the successful implementation of the process, from initial testing through to commissioning at one of the world's largest refractory gold mines is described.
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In most refractory raw gold minerals, more than 90% of gold is distributed in sulfide, encapsulated or embedded in the crystal lattice of pyrite and/or arsenopyrite in the form of fine or sub-fine particles. ... As a complex mineral, the anodic oxidation process of gold concentrate is also unclear. Therefore, this study seeks to better ...
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The extraction of gold (Au) from refractory ores poses major challenges due to the inclusion of gold particles in sulfide minerals. In this study, an alternative and highly efficient oxidative …
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Minerals Engineering, Vol. 4, Nos 7-1 I, pp. 1029-1041, 1991 0892-6875/91 $3.00 + 000 Printed in Great Britain 1991 Pergamon Press plc PROCESSING OF REFRACTORY GOLD ORES K.S. FRASER, R.H. WALTON and J.A. WELLS Kilborn Limited, 2200 Lake Shore Blvd. West, Toronto, Ontario MSV IA4, Canada ABSTRACT During the last ten years, increasing …
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Microbial oxidation is a technique based on the metabolic behavior of bacteria and archaea. The microorganisms used in microbial oxidation mainly include Acidithiobacillus, Sulfobacillus, Leptospirillum and other genera (Johnson, 1998, Mahmoud et al., 2017). These microorganisms can oxidize Fe 2+ and inorganic sulfur compounds into Fe 3+, H + and SO 4 …
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Bioleaching has emerged as a green technology with promising applications in mining industries in the context of recovery of precious metals from mineral ores. The authors …
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The raw materials used in this research were two different sulfide minerals—pyrite concentrate and sulfide gold concentrate—sourced from different companies in China. ... Column bio-oxidation of low-grade refractory gold ore containing high-arsenic and high-sulfur: insight on change in microbial community structure and sulfide surface ...
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Gold Extraction from a Refractory Sulfide Concentrate by Simultaneous Pressure Leaching/Oxidation ... Characterization of the ores showed that pyrite and quartz were the main minerals present in ...
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Nevertheless, the pressure oxidation of double refractory materials containing carbonaceous matter in addition to sulfides results in substantial gold losses due to autoclave preg-robbing.
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Minerals En&ineering, Vol. 7, Nos 2/3, pp. 239-249, 1994 0892--6875/94 $6.00+0.00 Printed in Great Britain 1993 Pergamon Press Ltd APPLICATION OF eMAX IMAGE ANALYSIS TO PRESSURE OXIDATION OF REFRACTORY GOLD ORES J.M. LAUKKANEN and J.O. LEPPINEN Technical Research Centre of Finland, Laboratory of Mineral Processing, FIN …
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To increase the efficiency of gold extraction, oxidation pretreatment before gold leaching decomposes the sulfide matrix in refractory ores and liberates gold particles. Pressure oxidation and biological oxidation are common hydrometallurgical methods for sulfide mineral degradation [1].
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The ozonation of refractory minerals can improve gold extraction through direct treatment or indirect oxidation. It minimizes gold entrapping with refractory minerals by …
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The treatments studied for refractory minerals are roasting, bioxidation, chemical oxidation in acid or alkaline medium, and pressure oxidation. (3,8−10) When the mineral's refractoriness is due to the gold within the sulfides, oxidative pretreatment turns out to be the appropriate option; (3,8) that is, it is necessary to use strongly ...
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Most gold deposits occur associated with sulphides like pyrite and arsenopyrite; thus, precious metal dissolution is possible by oxidizing auriferous sulfide concentrate using simultaneous pressure oxidation and cyanidation.
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Pretreatment using microwave-assisted roasting with NaClO 3 as an additive to the oxidizing agent is a new method of processing refractory gold ore. Oxidation was studied through sulfur and chlorine mass balance analysis and the degree of metal extraction from sulfide …
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This could include microbes engineered to tolerate higher cyanide concentrations, target specific mineral surfaces, or improve the breakdown of refractory minerals (Wang et al. 2021). A deeper understanding of the microbial communities involved in biocyanidation can lead to the discovery of novel microorganisms with unique metabolic capabilities.
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Download scientific diagram | Process flow of bio-oxidation and biocyanidation of Au bearing refractory mineral ores. from publication: Bio-Oxidation and Biocyanidation of Refractory Mineral Ores ...
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The severity of environmental pollution poses a serious threat to human health, and especially organic pollution is more complex and difficult to trea…
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Pyrite is a relatively refractory mineral in the replacement sequence; marcasite oxidizes more quickly than pyrite (Mason and Berry, 1968), and pyrrhotite oxidation is as much as two orders of magnitude faster than oxidation of pyrite (Nicholson and Scharer, 1994). Laboratory observations of Fe sulfide oxidation are corroborated by the para-
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Refractory gold mining often involves complex extraction processes, such as pressure oxidation or bioleaching, which can release harmful chemicals and pollutants into the …
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Rusanen et al. [11] argue that oxygen pressure is the most important factor influencing the oxidation of refractory minerals. Figure 4. Effects of temperature and pressure on Au extraction at 6 g/L cyanide concentration. Minerals 2023, 13, 116 6 of 11 From Figure 4, we can see that gold dissolution of 89.51% was obtained at pressure leaching ...
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The paper covers many literature reports of processes using nitrogenous species as an oxidant for processing refractory gold ores, especially development in the pretreatment of refractory …
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Fusion Techniques for the Oxidation of Refractory Actinide Oxides Tracy S. Rndisill and David G. Karraker March 1999 Westinghouse Savannah River Company ... actinide oxides with a series of materials commonly used to decompose minerals, glasses, and other refractories as a pretreatment to dissolution and subsequent recovery operations. In these ...
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SEM analysis was carried out to complete the study of the phase change of compounds in the oxidation of mineral sulfides. Roasting of refractory gold ore with a composition of 180 kg NaClO 3 and 180 kg water/ton ore reached a temperature of 470 °C at a microwave power of 400 watts for 30 minutes. Total oxidized sulfur reached 90.6%, while only ...
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Pressure oxidation (POX) is an effective method for base metal extraction and a pretreatment of refractory gold ores. A residue from pressure leaching of chalcopyrite concentrate was collected and investigated for gold recovery and deportment of metals. A comprehensive mineralogical analysis and gold deportment study were conducted using techniques including …
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With the evolving landscape of gold mineral resource development and utilization, the easily treatable gold resources are continuously decreasing, while refractory gold minerals are becoming the most important resources in the field of gold extraction. In these original ores, most of the gold is encapsulated in the lattice of pyrite and arsenopyrite, resulting in difficulty of gold …
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The primary objective of refractory material pretreatment is the oxidation of gold-hosting minerals, breaking down their crystal structures and releasing the gold particles (Zvontsov & …
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Among several alternatives, bio-oxidation has emerge as a green technique that liberates gold from refractory sulphide mineral matrixes. Show abstract The less predictive nature of alkaline cyanide leaching, owing to its complex functional relationships, render most processing plants unproductive and subsequent shutdown.
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In unoxidized (refractory) ores, the micron-sized gold is associated with sulfide minerals and organic carbon such as kerogen and asphaltine. Oxidation of the Mercur deposit developed upwards progressively from the bottom of the deposit such that the upper portion of the deposit contains refractory ore.
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Biological oxidation of refractory ores has become a more preferable pre-treatment method of sulphides and carbonaceous gold ores compared to roasting and pressure oxidation, which are costly and environmental unfriendly. Bio-oxidation involves the use of strains of bacterial to catalyze the decomposition of sulphide minerals.
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In addition, SiO 2 and FeAsS are also the major minerals for the sulfide refractory gold ore. Table 2. Chemical composition of the sulfide refractory gold ore and pyrite (mass percent, %). Empty Cell ... Redox potential measurement during pressure oxidation (POX) of a refractory gold ore. Canadian Metallurgical Quarterly, 57 (4) (2018), pp. 382 ...
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Common refractory gold bearing minerals include arsenopyrite, pyrite and copper sulphides, which are highly resistant to extraction by standard cyanidation and usually require pre-treatment for cyanidation to be effective. ... High Pressure Oxidation (HPOx): Refractory ores where gold is contained within sulphides, such as pyrite or ...
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