Biooxidation of a High-Grade Arsenopyritic Gold Ore Using a Mixed Culture of Moderate Thermophilic Microorganisms

2017 ◽  
Vol 262 ◽  
pp. 215-218
Author(s):  
Hoda Abdolahi ◽  
Ali Ahmadi ◽  
Hamid Zilouei ◽  
Maryam Khezri
Keyword(s):  
Mixed Culture ◽  
Pulp Density ◽  
Critical Parameters ◽  
High Grade ◽  
Stirred Tank Bioreactor ◽  
Thermophilic Microorganisms ◽  
Iron Extraction ◽  
Moderately Thermophilic ◽  
Gold Ore ◽  
Shake Flasks

This study investigated the biooxidation of a high-grade refractory gold ore from the Zarshouran mine (West Azarbaijan, Iran) in shake flasks and a stirred tank bioreactor (STBR) using a mixed culture of moderately thermophilic microorganisms. The influence of four critical parameters including, pH, biooxidation time, nutrient medium type and pulp density on the iron and arsenic extraction as well as gold cyanidation were evaluated in a full factorial design in shake flasks at 45 °C. Maximum iron extraction was obtained in M9K medium, pulp density of 5% (w/v), 15 days of biooxidation time and the pH of 1.6. Biooxidation in the STBR was carried out at the pulp densities of 10% and 20% (w/v), the pH of 1.7 in the M9K medium, in which dissolved oxygen, pH, redox potential, iron and arsenic concentrations were measured during the process. It was found that 61% decrement of sulphur content in the STBR led to recover 80% of gold, which was 43% higher than that in the conventional cyanidation process. It can be concluded that the oxidation of refractory arsenopyrite gold ore can achieved using a moderately thermophilic biooxidation culture.

Bioleaching of chalcopyrite by mixed culture of moderately thermophilic microorganisms

2007 ◽  
Vol 14 (4) ◽  
pp. 474-478 ◽  
Author(s):  
Chang-bin Wu ◽  
Wei-min Zeng ◽  
Hong-bo Zhou ◽  
Bo Fu ◽  
Ju-fang Huang ◽  
...  
Keyword(s):  
Mixed Culture ◽  
Thermophilic Microorganisms ◽  
Moderately Thermophilic

Types, structure and location of fractured gold pockets

2021 ◽  
pp. 62-75
Author(s):  
Evgeny Nekrasov ◽  
Alexander Nekrasov
Keyword(s):  
Baikal Region ◽  
Western Siberia ◽  
South Urals ◽  
High Grade ◽  
Gold Ores ◽  
Gold Ore

Fractured gold ore pockets of various types are classified and their structure is described in detail. This will allow explorationists to confirm high-grade gold ores, which is especially important in underground deposit mining. Gold pockets were mapped and analyzed by the author at deposits in Uzbekistan (Muruntau, Daugyz, Charmitan, Kokpatas), eastern Trans-Baikal region (Darasun, Balei, etc.) and Kochkarskoye (South Urals). Also, the paper describes the material collected by the author at gold pockets in Natalkinskoye, Nezhdaninskoye, Pavlik and Kyuchus deposits in Yakutia, Berikul in Western Siberia, Bakyrchik in Kazakhstan as well as deposits from Australia (Kalgoorlie, Northman, etc.), USA (Comstock, etc.), Canada (Porcupine), among others.

scholarly journals Bio-Oxidation of a Double Refractory Gold Ore and Investigation of Preg-Robbing of Gold from Thiourea Solution

Metals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1216
Author(s):  
Rui Xu ◽  
Qian Li ◽  
Feiyu Meng ◽  
Yongbin Yang ◽  
Bin Xu ◽  
...  
Keyword(s):  
Mixed Culture ◽  
Active Sites ◽  
Gold Recovery ◽  
Ftir Analysis ◽  
Gold Extraction ◽  
Gold Ores ◽  
Gold Ore ◽  
Thiourea Solution ◽  
Refractory Gold ◽  
Pure Cultures

Carbonaceous sulfidic gold ores are commonly double refractory and thus require pretreatment before gold extraction. In this paper, the capacity of pre-bio-oxidation can simultaneously decompose sulfides or deactivate carbonaceous matters (CM) from a double refractory gold ore (DRGO) using pure cultures of A. ferrooxidans or L. ferrooxidans, and a mixed culture containing A. ferrooxidans and L. ferrooxidans was investigated. The results showed that direct thiourea leaching of the as-received DRGO yielded only 28.7% gold extraction, which was due to the encapsulation of sulfides on gold and the gold adsorption of CM. After bio-oxidation, thiourea leaching of the DRGO resulted in gold extraction of over 75–80%. Moreover, bio-oxidation can effectively reduce the adsorption of carbon to gold. XRD, SEM-EDS and FTIR analysis showed that many oxygen-containing groups were introduced on the surface of DRGO during bio-oxidation, while the C=C bond was cleaved and the O–C–O and C–N bonds were degraded, causing a decrease in active sites for gold adsorption. Moreover, passivation materials such as jarosite were formed on the surface of DRGO, which might reduce the affinity of CM for gold in solutions. In addition, the cleavage of the S–S band indicated that sulfides were oxidized by bacteria. This work allows us to explain the applicability of pre-bio-oxidation for degrading both sulfides and CM and increasing gold recovery from DRGO in the thiourea system.

scholarly journals Growth requirements of thermophilic aerobic microorganisms in mixed cultures for the treatment of strong wastes

1999 ◽  
Vol 40 (1) ◽  
pp. 53-60 ◽  
Author(s):  
G. Sürücü
Keyword(s):  
Mixed Culture ◽  
Maximum Growth ◽  
Effect Of Temperature ◽  
Nutritional Requirements ◽  
Nitrogen And Phosphorus ◽  
Thermophilic Microorganisms ◽  
Naturally Occurring ◽  
Growth Requirements ◽  
Phosphorus Sources ◽  
Pure Cultures

The nutritional and temperature requirements of a naturally occurring mixed culture of thermophilic microorganisms were studied. Investigations concerning the effect of temperature on the growth characteristics of the mixed culture showed that the rate of growth was highest between 55 and 58°C. Furthermore, it was found that the minimal nutritional requirements for maximum growth of these microorganisms included methionine, magnesium, calcium, and the necessary carbon, nitrogen and phosphorus sources. It was shown that a mixed culture was nutritionally less fastidious than the pure cultures of individual organisms isolated from the mixed culture; this observation illustrated the possibility of symbiotic growth of thermophilic microorganisms insofar as meeting their individual nutritional requirements.

Influence of particle size on copper recovery from sulfide ore by the moderately thermophilic microorganisms

2019 ◽  
Vol 116 (1) ◽  
pp. 119
Author(s):  
Wen-bo Zhou ◽  
Kai Li ◽  
Yu-guang Wang ◽  
Li-juan Zhang ◽  
Hai-na Cheng ◽  
...  
Keyword(s):  
Particle Size ◽  
Xrd Analysis ◽  
Microbial Interactions ◽  
Copper Recovery ◽  
Mineral Particle ◽  
Copper Ore ◽  
Thermophilic Microorganisms ◽  
Moderately Thermophilic ◽  
Before And After ◽  
Leaching Condition

The bioleaching of copper ore by the defined moderately thermophilic consortium containing Leptospirillum ferriphilum and Acidithiobacillus caldus was carried out in the bench-scale column. Bioleaching experiments showed that the leaching rate was 25% higher than that of a conventional leaching and the acid consumption was reduced by 33% at the optimal leaching condition. Meanwhile, the effect of different particle sizes on the rate of the copper leaching was also investigated, and it was shown that the particle size affects the bioleaching rate significantly in the range of 5–25 mm, in which approximately 89.27% of copper was extracted at 5–10 mm, while only 57.08% at 15–25 mm. The results obtained by X-ray diffraction (XRD) analysis of the mineral samples before and after microbial and chemical leaching revealed that the decrease in particle size of the minerals resulted in an enhancement of complex microbial interactions. Especially for the particle size of 5–10 mm, a significant amount of elemental sulfur and jarosite formed on the surface of the mineral, while it was further confirmed that critical microbe-mineral interactions have taken place on the mineral surface. The results indicated that mineral particle size is an integral factor to improve the copper recovery from ore in heap leaching operation. This will provide a reference to the heap construction for the bioleaching.

Experimental Study on the Cyanidation of a Low-Grade Gold with High Content of Arsenic in Myanmar

2013 ◽  
Vol 734-737 ◽  
pp. 1041-1044
Author(s):  
Peng Yang ◽  
Gui Fang Zhang ◽  
Qing Rong Yang
Keyword(s):  
Experimental Study ◽  
Pulp Density ◽  
Low Grade ◽  
Leaching Rate ◽  
Mixing Effect ◽  
Gold Ore ◽  
Lime Water ◽  
Content Of Gold

The content of gold ore in Wa region of Myanmar is 3.52 g/t ~5.87g/t, and it contains 9.32% arsenic, it belongs to awkward gold ore with gold embeds in pyrite as fine granular. so the drawbacks of low leaching rate and wasting of resources existed in the early cyanide production. A technology of adjusting pH in lime water and further leaching after regrinding was confirmed by contrasting the mixing effect in different reagent. The experiment results showed that a leaching rate of 81.63% has been obtained by adopting the conditions which pulp density is 40%, the pH of pulp adjusted in lime water is 10, the total NaCN dosage of three additions is 3 and the material is reground before third addition.

Origin of High-Grade Gold Ore, Source of Ore Fluid Components, and Genesis of the Meikle and Neighboring Carlin-Type Deposits, Northern Carlin Trend, Nevada

2003 ◽  
Vol 98 (6) ◽  
pp. 1069-1105 ◽  
Author(s):  
P. Emsbo ◽  
A. H. Hofstra ◽  
E. A. Lauha ◽  
G. L. Griffin ◽  
R. W. Hutchinson
Keyword(s):  
High Grade ◽  
Gold Ore ◽  
Carlin Trend
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