Biooxidation of persistent gold-bearing ore concentrate of the Bestobe deposit

Булаев, А. Г.; Boduen, A. Ya.; Ukraintsev, I. V.

doi:10.17580/or.2019.06.02

Cited by 3 publications

(12 citation statements)

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“…Therefore, the goal of the present work was to evaluate the possibility to increase the efficiency of sulfide gold-bearing concentrate biooxidation in stirred tank reactors by means of addition of carbon sources required for the constructive metabolism of microorganisms. The results obtained in the present work were compared with those obtained at lower temperature (45 and 40 • C, respectively) in our previous work [33] to evaluate the effect of additional carbon nutrition on microbial population adaptation to temperature increase. In contrast to our previous work [32], where the possibility of CO 2 and molasses application was studied in batch mode, in the present work, experiments were performed in continuous mode that in turn allowed us to evaluate the effect of different carbon sources under conditions similar to those used in industrial scale processes.…”

Section: Introductionmentioning

confidence: 90%

“…The main sulfide minerals of the concentrate were pyrite (28.3%) and arsenopyrite (15.8%). In our previous work [33], we studied biooxidation of similar concentrate obtained from the same ore, which differed slightly in chemical composition from that used in the present article. The concentrate was refractory, since gold recovery by direct cyanidation did not exceed 43%, while biooxidation in continuous mode at 40 • C and residence time of 5 days made it possible to oxidize 79% of sulfide sulfur and to increase the gold recovery by cyanidation up to 92.5-93.5% [33].…”

Section: Concentratementioning

confidence: 99%

“…In our previous work [33], we studied biooxidation of similar concentrate obtained from the same ore, which differed slightly in chemical composition from that used in the present article. The concentrate was refractory, since gold recovery by direct cyanidation did not exceed 43%, while biooxidation in continuous mode at 40 • C and residence time of 5 days made it possible to oxidize 79% of sulfide sulfur and to increase the gold recovery by cyanidation up to 92.5-93.5% [33]. In the present work, we have compared the results obtained with those shown in the work [33] as both concentrates were produced from the same ore and therefore were very similar both in chemical and mineral composition.…”

Section: Concentratementioning

confidence: 99%

“…We used liquid mineral nutrient medium, which was previously used in sulfide concentrate biooxidation experiments [32,33], containing the following components (g/L): (NH 4 ) 2 SO 4 -0.75, KCl-0.05, MgSO 4 × 7H 2 O-0.125, K 2 HPO 4 -0.125, distilled water-1.0 L. The pH was adjusted by adding either concentrated sulfuric acid or CaCO 3 to the medium.…”

Section: Experimental Setup and Biooxidatonmentioning

confidence: 99%

“…Microbial population formed during continuous biooxidation of sulfide concentrate at 40 • C [33] was used in the present work. After experiments performed at 40 • C, the temperature in the reactors was increased and microbial population was adapted to elevated temperature (45 • C).…”

Section: Microbial Population Analysismentioning

confidence: 99%

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Carbon Sources as a Factor Determining the Activity of Microbial Oxidation of Sulfide Concentrate at Elevated Temperature

Булаев

Boduen

2022

Minerals

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The goal of the present work was to evaluate the possibility of improving the efficiency of the stirred tank reactor biooxidation of sulfide gold-bearing concentrate by means of addition of carbon sources required for the constructive metabolism of microorganisms. Biooxidation experiments were performed on gold-bearing pyrite-arsenopyrite concentrate in continuous mode at 45 °C to determine the influence of additional carbon sources (carbon dioxide and molasses) on sulfide mineral oxidation. The use of CO2 allowed increasing the efficiency of the biooxidation and the extents of sulfide sulfur (Ss) oxidation and gold recovery were 79% and 84%, respectively. Biooxidation in a control experiment (without additional carbon sources) and when using molasses allowed achieving 39% and 66% oxidation of Ss as well as 73% and 81% of gold recovery. Analysis of the microbial populations formed in biooxidation reactors using NGS methods demonstrated that CO2 application led to an increase in the relative abundance of the genus Sulfobacillus. Thus, it was determined that application of additional carbon source makes it possible to manage the biooxidation process, affecting both sulfide mineral oxidation and microbial population composition.

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Section: Introductionmentioning

confidence: 90%

Section: Concentratementioning

confidence: 99%

Section: Concentratementioning

confidence: 99%

Section: Experimental Setup and Biooxidatonmentioning

confidence: 99%

Section: Microbial Population Analysismentioning

confidence: 99%

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Carbon Sources as a Factor Determining the Activity of Microbial Oxidation of Sulfide Concentrate at Elevated Temperature

Булаев

Boduen

2022

Minerals

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Prospects for refractory gold-sulfide ore processing

Grigoreva,

Boduen

2024

Izv.VUZ. Tsvet. Met.

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Cyanide-refractory ores constitute 30 % of the world’s gold mineral resource base. With the global decrease in the availability of high-grade and free-milling ores, low-quality ores, including those rich in sulfur and arsenic, are increasingly being processed. The authors have conducted an assessment of the primary factors complicating the leaching process of refractory gold. These factors include the influence of gold distribution within the ore, the presence of preg-robbing effects, and the impact of cyanicidal minerals, notably pyrrhotite, on the leaching process. Sulfide minerals significantly affect the kinetics of gold leaching and associated reagent costs. The behavior of Fe5S6 is elucidated through the concept of “chemical depression”. Under cyanide leaching conditions, pyrrhotite actively and directly reacts with NaCN/KCN, undergoing surface oxidation by dissolved oxygen in the pulp. This leads to the formation of ferrocyanide complexes and rhodanides, which are unable to leach gold. Presently, there are two approaches to enhance the process parameters of refractory ore processing technology. The first approach involves the inclusion of preparation operations for cyanidation, aimed at liberating gold from the sulfide matrix (including hydrometallurgical and pyrometallurgical oxidation technologies and mechanical activation). An alternative approach is to use alternative reagents as leaching agents (notably thiourea, sodium and ammonium thiosulfates, and halides). The article explores means of modifying the technological process for gold extraction when ores contain substantial amounts of pyrrhotite or concentrates.

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Combined Bacterial and Pressure Oxidation for Processing High-Sulfur Refractory Gold Concentrate

Boduen,

Zalesov,

Melamud

et al. 2023

Processes

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Microbially assisted bio-oxidation of sulfide concentrates in stirred-tank reactors (stirred-tank reactor bio-oxidation (STRB)) and acid pressure oxidation (POX) are widely used to pretreat refractory sulfide concentrates and increase gold extraction via cyanidation. Continuous STRB requires a comparatively long residence time; however, in some cases, it cannot effectively oxidize some sulfide minerals. POX enables oxidation in a short residence time. At the same time, if a processed concentrate contains a large amount of sulfur, it decreases the ratio of the solid mineral phase to liquid (pulp density) during POX and limits its economic attractiveness. In the present work, experiments were performed to investigate the problems associated with both processing methods for refractory sulfide concentrates. The experiments combined both treatments (STRB and POX) based on the example of a pyrite–arsenopyrite gold-bearing concentrate. The gold recovery from the untreated concentrate via cyanidation reached 58%. Continuous STRB for 2, 4, and 6 days oxidized 43, 74, and 79% of the sulfide sulfur (Ss), respectively. The gold recovery rates from the bio-oxidation residues were 68, 82, and 88%, respectively. The pressure oxidation of both the concentrate and STRB residues increased Ss oxidation by 97–99% and gold recovery by 96–97%. For 2 days, STRB decreased the Ss content and increased the possible liquid-to-solid ratio for POX. The combined processes result in a new promising direction because the POX stage allows high gold recovery, whereas combining STRB and POX provides products for further POX in terms of Ss content and increases POX productivity.

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Biooxidation of persistent gold-bearing ore concentrate of the Bestobe deposit

Cited by 3 publications

References 0 publications

Carbon Sources as a Factor Determining the Activity of Microbial Oxidation of Sulfide Concentrate at Elevated Temperature

Carbon Sources as a Factor Determining the Activity of Microbial Oxidation of Sulfide Concentrate at Elevated Temperature

Prospects for refractory gold-sulfide ore processing

Combined Bacterial and Pressure Oxidation for Processing High-Sulfur Refractory Gold Concentrate

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