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

Minerals ◽  
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.

Bioleaching of Low-Grade Chalcopyrite Ore by the Thermophilic Archaean Acidianus brierleyi

2017 ◽  
Vol 262 ◽  
pp. 237-241 ◽  
Author(s):  
Norizoh Saitoh ◽  
Toshiyuki Nomura ◽  
Yasuhiro Konishi
Keyword(s):  
Environmentally Friendly ◽  
Copper Recovery ◽  
Copper Extraction ◽  
Low Grade ◽  
Column Reactor ◽  
Stirred Reactor ◽  
Acidianus Brierleyi ◽  
Environmentally Friendly Process ◽  
Chalcopyrite Ore

The thermophilic archaean, Acidianus brierleyi, was examined for its feasibility to bioleach copper from a low-grade chalcopyrite ore (1.15 % copper, 20.4 % iron and 2.63 wt% sulfur) at 65°C and pH 1.8-2.5. The chalcopyrite leaching was markedly accelerated in the presence of A. brierleyi, and an extremely high 80% leaching of copper in the low-grade ore (25-38 μm particles) was achieved in 14 days in a batch stirred reactor. By comparison, the leaching of iron was very slow and only a slight 5 % iron was leached in 14 days in the presence or absence of A. brierleyi. In other words, A. brierleyi selectively leached chalcopyrite while magnetite leaching by A. brierleyi was negligible. Moreover, bioleaching of the low-grade ore (53-75 μm particles) yielded 55% copper recovery after 20 days of operation in a column reactor. The good results for the copper bioleaching in the column reactor are very similar to those in the stirred reactor. These results lead to the conclusion that the thermophile bioleaching with A. brierleyi is attractive as an economical and environmentally friendly process for good copper extraction from low-grade chalcopyrite ore.

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

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.

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

2014 ◽  
Vol 2014 ◽  
pp. 1-11
Author(s):  
Baba Ngom ◽  
Yili Liang ◽  
Xueduan Liu
Keyword(s):  
Community Analysis ◽  
Copper Tolerance ◽  
Microbial Community Analysis ◽  
Copper Extraction ◽  
Low Grade ◽  
Acidithiobacillus Thiooxidans ◽  
Physiological Level ◽  
Copper Mine ◽  
Different Strains ◽  
Leaching Efficiency

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.

The Effects of Drying Techniques on Clay-Rich Soil Texture

1974 ◽  
Vol 32 ◽  
pp. 466-467
Author(s):  
T. G. Naymik
Keyword(s):  
Critical Point ◽  
Liquid Nitrogen ◽  
Liquid Nitrogen Temperature ◽  
Drying Methods ◽  
Air Drying ◽  
Freeze Dried ◽  
Critical Point Drying ◽  
Set Up ◽  
The Relationship ◽  
Quartz Grains

Three techniques were incorporated for drying clay-rich specimens: air-drying, freeze-drying and critical point drying. In air-drying, the specimens were set out for several days to dry or were placed in an oven (80°F) for several hours. The freeze-dried specimens were frozen by immersion in liquid nitrogen or in isopentane at near liquid nitrogen temperature and then were immediately placed in the freeze-dry vacuum chamber. The critical point specimens were molded in agar immediately after sampling. When the agar had set up the dehydration series, water-alcohol-amyl acetate-CO2 was carried out. The objectives were to compare the fabric plasmas (clays and precipitates), fabricskeletons (quartz grains) and the relationship between them for each drying technique. The three drying methods are not only applicable to the study of treated soils, but can be incorporated into all SEM clay soil studies.

Bioleaching of copper from a low-grade chalcopyrite ore

1981 ◽  
Vol 31 (1) ◽  
pp. 358-362 ◽  
Author(s):  
Desh Deepak ◽  
Kumudeswar Das
Keyword(s):  
Low Grade ◽  
Chalcopyrite Ore

scholarly journals Geochemistry of Fluvial Sediments from Geregu, Southwest Nigeria

2017 ◽  
Vol 64 (1) ◽  
pp. 35-52 ◽  
Author(s):  
Emmanuel E. Adiotomre ◽  
Innocent O. Ejeh ◽  
Edwin O. Adaikpoh
Keyword(s):  
Inductively Coupled Plasma ◽  
Tectonic Setting ◽  
Passive Margin ◽  
Fluvial Sediments ◽  
Geochemical Analysis ◽  
Sediment Samples ◽  
Inductively Coupled ◽  
Southwest Nigeria ◽  
Plasma Mass Spectrometry ◽  
Quartz Grains

Abstract Geochemical analysis of fluvial sediments on the banks of River Ero using inductively coupled plasma mass spectrometry illustrates their maturity, provenance and tectonic setting. The analysed sediment samples show low SiO2/Al2O3 ratios of 2.92-2.99 (units FL_A, FL_B and FL_E) and high SiO2/Al2O3 ratios of 4.064-4.852 (units FL_C, FL_D, FL_F and FL_G). Sediments were geochemically classified as shales (units FL_A, FL_B and FL_E) and greywackes (units FL_C, FL_D, FL_F and FL_G). Variability in sediment maturity (FL_F > FL_G >FL_C >FL_D >FL_A > FL_B > FL_E) parallels a decreasing order in the ratios of SiO2/Al2O3 and K2O/Al2O3, as well as the proportion of quartz grains and matrix components. Evidence from Al2O3/TiO2, K2O, Rb, La/Co, Th/Co, Cr/ Th, Th/Cr, La/Th-Hf, Th-Hf-Co and rare earth element contents of sediment samples suggest felsic protoliths of upper continental crust in a passive margin tectonic setting. An insignificant contribution of mafic components from the source is, however, inferred based on the Ni and Cr contents of the sediment samples. Combined Eu anomalies <0.85 and (Gd/Yb)n ratios <2.0 (1.53- 1.82, average 1.65) suggest post-Archean protoliths.

Probing the Reactivity of 2,4-Dichlorofuro[3,4-d]pyrimidin-7-one: A Versatile and Underexploited Scaffold to Generate Substituted or Fused Pyrimidine Derivatives

Synlett ◽  
2019 ◽  
Vol 30 (17) ◽  
pp. 2010-2014
Author(s):  
Paolo Vincetti ◽  
Gabriele Costantino ◽  
Maria Grazia Martina ◽  
Marco Radi
Keyword(s):  
Chemical Reactivity ◽  
Pyrimidine Derivatives ◽  
Reaction Conditions ◽  
One Pot ◽  
Microwave Assisted ◽  
Set Up

Herein, we describe the results of our investigation on the chemical reactivity and versatility of a poorly explored scaffold: 2,4-dichlorofuro[3,4-d]pyrimidin-7-one (3). Highly functionalized pyrimidines can be obtained with a divergent approach by reacting the key intermediate 3 with different amine nucleophiles under carefully controlled reaction conditions. The set-up of a microwave-assisted one-pot, two- or three-step protocol to rapidly generate 2,4,5,6-tetrasubstituted or fused pyrimidines is also reported.

scholarly journals Bacterial leaching kinetics for copper dissolution from a lowgrade Indian chalcopyrite ore

2013 ◽  
Vol 66 (2) ◽  
pp. 245-250 ◽  
Author(s):  
Abhilash ◽  
K.D. Mehta ◽  
B.D. Pandey
Keyword(s):  
Phase Identification ◽  
Low Grade ◽  
Bacterial Leaching ◽  
Copper Dissolution ◽  
Diffusion Controlled ◽  
Shrinking Core ◽  
Copper Mines ◽  
Chalcopyrite Ore ◽  
Best Fit

Bio-leaching of copper (0.3%) from a low grade Indian chalcopyrite ore of Malanjkhand copper mines, using a native mesophilic isolate predominantly Acidithiobacillus ferrooxidans (A.ferrooxidans), is reported. A bio-recovery of 72% Cu was recorded in the presence of this culture (not adapted), which increased to 75% with an ore adapted culture after 35 days at 35ºC and pH 2.0 with <50fim particles. The kinetic data showed best fit for the diffusion-controlled shrinking core model, exhibiting linear plots for [1- 2/3X-(1-X)2/3] vs time (X-fraction leached). Apparently, the role of the bacteria is to convert the ferrous ion to the ferric state, which oxidizes the chalcopyrite in order to dissolve copper, while maintaining a high redox potential. The activation energy value (E) was calculated to be 96 and 108 kJ/mol for the un-adapted culture and the ore adapted culture respectively in the temperature range 25-35ºC. This leaching mechanism was corroborated by XRD phase identification and SEM studies of the leach residue.

Optimization of staged bioleaching of low-grade chalcopyrite ore in the presence and absence of chloride in the irrigating lixiviant: ANFIS simulation

2016 ◽  
Vol 39 (7) ◽  
pp. 1081-1104 ◽  
Author(s):  
Ali Behrad Vakylabad ◽  
Mahin Schaffie ◽  
Ali Naseri ◽  
Mohammad Ranjbar ◽  
Zahra Manafi
Keyword(s):  
Low Grade ◽  
Presence And Absence ◽  
Chalcopyrite Ore
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