Cross-Comparison of Leaching Strains Isolated from Two Different Regions: Chambishi and Dexing Copper Mines

A cross-comparison of six strains isolated from two different regions, Chambishi copper mine (Zambia, Africa) and Dexing copper mine (China, Asia), was conducted to study the leaching efficiency of low grade copper ores. The strains belong to the three major species often encountered in bioleaching of copper sulfide ores under mesophilic conditions:Acidithiobacillus ferrooxidans,Acidithiobacillus thiooxidans, andLeptospirillum ferriphilum. Prior to their study in bioleaching, the different strains were characterized and compared at physiological level. The results revealed that, except for copper tolerance, strains within species presented almost similar physiological traits with slight advantages of Chambishi strains. However, in terms of leaching efficiency, native strains always achieved higher cell density and greater iron and copper extraction rates than the foreign microorganisms. In addition, microbial community analysis revealed that the different mixed cultures shared almost the same profile, andAt. ferrooxidansstrains always outcompeted the other strains.

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Comparison of Indigenous and Exogenous Mesophilic Bacteria for the Bioleaching of Low Grade Copper Ores

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.825.58 ◽

2013 ◽

Vol 825 ◽

pp. 58-61

Author(s):

Jia Lin Sun ◽

Ba Ba Ngom ◽

Yi Liu ◽

Hua Qun Yin ◽

Yi Li Liang ◽

...

Keyword(s):

Microbial Community ◽

Mixed Culture ◽

Community Analysis ◽

Copper Resistance ◽

Microbial Community Analysis ◽

Copper Extraction ◽

Low Grade ◽

Acidithiobacillus Thiooxidans ◽

Copper Mine ◽

Native Strains

Using indigenous microorganisms in biomining processes assures few ecological distortions and less time consumption for adaptation. However, there is a debate as to whether an indigenous microbial community is more efficient than one composed of microbial strains selected for specific physiological traits. In order to provide thoughtful opinions in such a debate, a cross-comparison of six strains isolated from two different regions: Chambishi Copper Mine (Zambia) and Dexing Copper Mine (China), was conducted. Physiological properties and leaching performancesof Acidithiobacillus ferrooxidans, Acidithiobacillus thiooxidans, and Leptospirillum ferriphilum in pure and mixed culture were studied. The results showed that strains within species presented similar traits while copper resistance was not species-specific. In terms of leaching efficiency, native strains always achieved higher cell density and greater iron and copper extraction rates than the exogenous. In addition, microbial community analysis revealed the different mixed culture shared almost the same profile, and At. ferrooxidans strains always outcompeted the other strains.

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Column Bioleaching of Low Grade Copper Sulfide Ore at Extreme Conditions for Most Mineral Processing Bacteria

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.825.318 ◽

2013 ◽

Vol 825 ◽

pp. 318-321 ◽

Cited By ~ 2

Author(s):

Gang Zou ◽

Zeng Ling Wu ◽

Xiao Kang Lai ◽

Lai Chang Zou ◽

Ren Man Ruan ◽

...

Keyword(s):

Iron Concentration ◽

Heap Leaching ◽

Operating Conditions ◽

Industrial Plant ◽

Copper Extraction ◽

Low Grade ◽

Extreme Conditions ◽

Leaching Rate ◽

Copper Leaching ◽

Leaching Efficiency

This study is prompted by the high leaching efficiency of Zijinshan copper bio-heap leaching industrial plant. Bioleaching columns with 100 mm diameter and 1 m height were used to investigate copper bioleaching at different operating conditions. Elevated temperature, high total iron concentration and high acidity significantly increased copper leaching rate as determined by solution and residue assays. At 60 °C with 50 g/L iron (initial Fe3+/Fe2+ gram ratio 2.5), pH 1.0 and no aeration, copper extraction was achieved 90% after 60 days. However, at 30°C, 5 g/L total Fe, pH 1.5 and no aeration, copper extraction reached 80% and 85% after 90 and 200 days, respectively. Real-time PCR assay showed that only 105 cells/ml and 2×105 cells/g are in solution and on the ore surface at the condition of 60 °C 50 g/L iron and pH 1.0, respectively. In addition, a similar leaching rate was observed in the tests with and without inoculation. The column without inoculation was directly irrigated with acid mine drainage (AMD). Our results indicate high copper leaching efficiency at extreme conditions for mineral oxidizing bacteria. Inoculation and aeration are not necessary in Zijinshan copper mine bio-heap leaching process.

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A Column Leaching Model of Low-Grade Chalcopyrite Ore: Mineral Preferences and Chemical Reactivity

Minerals ◽

10.3390/min10121132 ◽

2020 ◽

Vol 10 (12) ◽

pp. 1132

Author(s):

Heike Bostelmann ◽

Gordon Southam

Keyword(s):

Chemical Reactivity ◽

Copper Extraction ◽

Low Grade ◽

Acidithiobacillus Thiooxidans ◽

Geochemical Analysis ◽

Proton Activity ◽

Set Up ◽

Chalcopyrite Ore ◽

Quartz Grains ◽

Number Of Cells

Bioleaching models to examine copper extraction from low-grade chalcopyrite ores were set up to identify the influence of pyrite on leaching efficacy. A combination of scanning electron microscopy and geochemical analysis showed that extraction was marginally enhanced by the addition of pyrite when using a combination of Leptospirillum ferrooxidans, an iron oxidiser, Acidithiobacillus thiooxidans, a sulphur oxidising species and Acidithiobacillus ferrooxidans, an iron and sulphur oxidiser. Extensive biofilms formed on the pyrite surfaces (>106 cells/mm2) but were severely limited on chalcopyrite, possessing approximately the same number of cells as quartz grains, an internal non-nutrient control “substrate” (with ca. 2 × 103 cells/mm2). The presence of dissolved copper did not inhibit the growth of this consortium. Indirect “bioleaching” of chalcopyrite appears to be limited by proton activity at the chalcopyrite surface.

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The Influence of Pyrite on Galvanic Assisted Bioleaching of Low Grade Chalcopyrite Ores

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.262.93 ◽

2017 ◽

Vol 262 ◽

pp. 93-98

Author(s):

Biao Wu ◽

He Shang ◽

Min Lin Wu ◽

Jian Kang Wen

Keyword(s):

16S Rrna ◽

16S Rrna Gene ◽

Redox Potential ◽

Recovery Rate ◽

Phylogenetic Analyses ◽

Copper Recovery ◽

Copper Extraction ◽

Rrna Gene ◽

Low Grade ◽

Copper Mine

The experiment focused on the effect of pyrite on the dissolution of the ore from Saindak copper mine in Pakistan. The MLA results showed that the ore mainly consisted of chalcopyrite, which was associated closely with pyrite. The bioleaching process and galvanic promotion experiments of pyrite on the copper extraction were investigated. The data revealed that copper recovery rate could be up to 97.8% after the bioleaching process by extreme thermophilic acidophilic organisms for 30 days at 65 OC. The temperature and redox potential were the controlled factors to recover copper from the Saindak mineral. The phylogenetic analyses of 16S rRNA gene fragments revealed that organisms related to Metallosphaera cuprina strain Ar-4 and Sulfolobus sp. HB59 were most dominant. Pyrite could accelerate the dissolution of chalcopyrite as one galvanic assistant substance, which would be strengthened by elevating the temperature or in the presence of microorganisms.

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