Biological pretreatment of carbonaceous matter in double refractory gold ores: A review and some future considerations

Konadu, Kojo T.; Mendoza, Diego M.; Huddy, Robert J.; Harrison, Susan T.L.; Kaneta, Takashi; Sasaki, Keiko

doi:10.1016/j.hydromet.2020.105434

Cited by 24 publications

(4 citation statements)

References 104 publications

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“…This was the key reason for a higher microbe population as compared to a closed independent system; which was adverse to microbe growth and oxidation in batch bio-oxidation process. Lastly, the kinetics and relative sulfide acid concentration in the continuous bio-oxidation process is much higher than batch bio-oxidation based on reactions (1) and (2).…”

Section: Influence Factors On Bio-oxidation Kineticsmentioning

confidence: 99%

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Comparative Study on Refractory Gold Concentrate Kinetics and Mechanisms by Pilot Scale Batch and Continuous Bio-Oxidation

Huang

Yang

2021

Minerals

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Most studies conducted have focused on the pulp density, Fe3+ concentration and sulfuric acid concentration, etc., of bio-oxidation, and few have reported on the influence of different bio-oxidation methods on kinetics. In this study, a comparative investigation on refractory gold concentrate by batch and continuous bio-oxidation was conducted, with the purpose of revealing the kinetics influence. The results showed that improving the removal rates of the gold-bearing pyrite (FeS2) and arsenopyrite (FeAsS) yielded the best results for increasing gold recovery. The removal rates of S, Fe and relative gold recovery linearly increased when compared to the second-order equation increase of the As removal rate in both batch and continuous bio-oxidation processes. The removal kinetics of S and Fe by continuous bio-oxidation was 12.02% and 12.17% per 24 h day, approximately 86.64% and 51.18% higher than batch bio-oxidation, respectively. The higher removal kinetics of continuous bio-oxidation resulted from a stepwise increase in microbe growth, a larger population and higher dissolved Fe3+ and H2SO4 concentration compared to a linear increase by batch bio-oxidation. The cyanidation gold recovery was as high as 94.71% after seven days of continuous bio-oxidation, with the gold concentrate sulfur removal rates of 83.83%; similar results will be achieved after 13 days by batch bio-oxidation. The 16sRNA sequencing showed seven more microbe cultures in the initial residue than Acid Mine Drainage (AMD) at genus level. The quantitative real-time Polymerase Chain Reaction (PCR) test showed the four main functional average microbe populations of Acidithiobacillus, Leptospirillum, Ferroplasma and Sulfobacillus in continuous bio-oxidation residue as 1.08 × 103 higher than in solution. The multi-microbes used in this study have higher bio-oxidation activity and performance in a highly acidic environment since some archaea co-exist and co-contribute.

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Section: Influence Factors On Bio-oxidation Kineticsmentioning

confidence: 99%

“…Approximately one-third of the gold deposits in the world are refractory gold ores [1,2]. Roasting [3], pressure oxygen oxidation [4], bio-oxidation [5] and chemical oxidation [6,7] are the commercial pretreatment technologies normally used to improve gold recovery before cyanidation from refractory gold ores.…”

Section: Introductionmentioning

confidence: 99%

Comparative Study on Refractory Gold Concentrate Kinetics and Mechanisms by Pilot Scale Batch and Continuous Bio-Oxidation

Huang

Yang

2021

Minerals

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“…The results of Kojo T. Konadu et al [18][19] showed that lignin degrading enzymes preferentially attacked defective graphite and dissolved some decomposition byproducts in carbonaceous substances. After continuous biological treatment, the gold recovery rate increased from 44% to 93%.…”

Section: Biological Oxidationmentioning

confidence: 99%

Research status of refractory treatment technology of carbon-bearing gold ores

Zhang,

Li,

Zhu

et al. 2024

E3S Web Conf.

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Carbon-bearing gold ore is one of the important refractory gold resources, which can not be effectively utilized by conventional treatment methods. In this paper, the main reasons for the difficult treatment of carbon-containing gold ore, the material composition of carbonaceous matter and the mechanism of carbonaceous matter “robbing gold” are analyzed. At the same time, the working principles of several pretreatment methods are summarized, and the advantages and disadvantages of each pretreatment method are analyzed, so as to provide strong technical support for the future development of carbon-bearing gold ores in China.

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“…However, carbonaceous matter is not well separated from sulfide minerals, so carbonaceous matter generally remains in the flotation concentrate [8]. It is no exaggeration to say that there is a global need for technological development to improve the gold recovery from DRGO [9].…”

Section: Introductionmentioning

confidence: 99%

Significance of Acid Washing after Biooxidation of Sulfides in Sequential Biotreatment of Double Refractory Gold Ore from the Syama Mine, Mali

et al. 2021

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Environmentally friendly pretreatment of double refractory gold ores (DRGO) to improve gold recovery without emitting pollutant gas is challenging. Sequential biotreatment, including iron-oxidizing microorganisms to decompose sulfides, followed by the enzymatic decomposition of carbonaceous matter, was recently developed. The effect of acid washing by 1 M HCl for 24 h between two bioprocesses was evaluated using a real double refractory gold ore from the Syama mines, Mali, which includes 24 g/t of Au and 5.27 wt% of carbon with a relatively higher graphitic degree. The addition of the acid washing process significantly improved gold recovery by cyanidation to yield to 84.9 ± 0.7% from 64.4 ± 9.2% (n = 2). The positive effects of acid washing can be explained by chemical alteration of carbonaceous matter to facilitate the accessibility for lignin peroxidase (LiP) and manganese peroxidase (MnP) in cell-free spent medium (CFSM), although the agglomeration was enhanced by an acid attack to structural Fe(III) in clay minerals. Sequential treatment of DRGO basically consists of the oxidative dissolution of sulfides and the degradation of carbonaceous matter prior to the extraction of gold; however, the details should be modified depending on the elemental and mineralogical compositions and the graphitic degree of carbonaceous matter.

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Biological pretreatment of carbonaceous matter in double refractory gold ores: A review and some future considerations

Cited by 24 publications

References 104 publications

Comparative Study on Refractory Gold Concentrate Kinetics and Mechanisms by Pilot Scale Batch and Continuous Bio-Oxidation

Comparative Study on Refractory Gold Concentrate Kinetics and Mechanisms by Pilot Scale Batch and Continuous Bio-Oxidation

Research status of refractory treatment technology of carbon-bearing gold ores

Significance of Acid Washing after Biooxidation of Sulfides in Sequential Biotreatment of Double Refractory Gold Ore from the Syama Mine, Mali

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