Investigation of the Effect of pH Operating Conditions on Bioleaching of Low-Grade Chalcopyrite in Column Reactors

2013 ◽  
Vol 825 ◽  
pp. 401-405
Author(s):  
Odilon M. Tshilombo ◽  
Tunde V. Ojumu
Keyword(s):  
Redox Potential ◽  
Iron Concentration ◽  
Leach Solution ◽  
Operating Conditions ◽  
Copper Recovery ◽  
Copper Extraction ◽  
Low Grade ◽  
Effect Of Ph ◽  
Dissolved Ions ◽  
High Concentrations

Bioleaching of low-grade sulphide minerals is now an established process, with much interest in chalcopyrite. However few studies have been carried out on ores containing silicates gangue materials. Chalcopyrite has been reported to be refractory at ambient temperature. Several factors that influence bioleaching kinetics are well documented such as particle size, pH, temperature, galvanic interaction and microbial activity. The purpose of this research was to investigated the effect of pH as well as pre-leaching on bioleaching of silicate rich and low-grade chalcopyrite using mixed thermophilic cultures, with a view to maximize copper solubilization rate in a column reactor operated at 70°C. The column was packed with low-grade chalcopyrite of the size range -20+15 mm. Leaching was monitored at specific time intervals (3 days) by measuring the pH, the redox potential, the copper and iron concentration in the solution. The results of the investigation have shown that copper extracted was highest at pH 1.3 and at moderately low redox potential (410 – 430 mV) using Ag/AgCl electrode, and that pre-leaching contributed insignificantly to the leaching rate. At pH 2.5, the copper extraction was low due to the jarosite. Furthermore, the analysis XRD of leached residues has indicated that the main passivating products were gypsum, jarosite, hexahydrite, and silica. However, although low pH resulted to high copper recovery, the results also showed that the pregnant leach solution (PLS) contained high concentrations of dissolved ions which might have inhibited the microbial activities.

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

2013 ◽  
Vol 825 ◽  
pp. 318-321 ◽  
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.

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

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.

Bioleaching of Low-Grade Copper Sulfide Ore Using a Colum Reactor

2009 ◽  
Vol 71-73 ◽  
pp. 409-412
Author(s):  
Wen Qing Qin ◽  
Yan Sheng Zhang ◽  
Shi Jie Zhen ◽  
Jun Wang ◽  
Jian Wen Zhang ◽  
...  
Keyword(s):  
Iron Concentration ◽  
Mixed Cultures ◽  
Copper Recovery ◽  
Low Grade ◽  
Leaching Rate ◽  
Ministry Of Education ◽  
Copper Ore ◽  
Copper Leaching ◽  
Pure Cultures ◽  
Mixed Bacteria

The effects of several variables on the column bioleaching of copper sulphide ore have been investigated. The copper ore contained chalcopyrite as the main sulfide minerals and bornite and chalcocite as the minor minerals. The experiment was carried out using bench-scale column leach reactors designed in Key Lab of Biometallurgy of Ministry of Education, which were inoculated with the pure mesophile bacteria (Acidithiobacillus ferrooxidans) and thermophile bacteria (Sulfobacillus), respectively, and the mixed bacteria which contain both iron- and sulfur-oxidizing bacteria. The results show that the mixed cultures were more efficient than the pure cultures alone and the maximum copper recovery 53.64% was achieved using the mixed cultures after 85 days. The leaching rate of chalcopyrite tended to increase with the increased dissolved ferric iron concentration. The effect of particle size on the rate of the copper leaching was also investigated, and it was shown that the copper bioleaching rate decreases as the amount of fines increase, which limits the permeability, thus decreases leaching rate. Jarosite and elemental sulphur formed in the column were characterized by the X-ray and EDS.

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.

scholarly journals Investigation of the optimal technology for copper leaching from old flotation tailings of the copper mine bor (Serbia)

10.30544/514 ◽  
2020 ◽  
Vol 26 (2) ◽  
pp. 209-222 ◽  
Author(s):  
Vesna Conić ◽  
Srđan Stanković ◽  
Branislav Marković ◽  
Dragana Božić ◽  
Jovica Stojanović ◽  
...  
Keyword(s):  
Iron Concentration ◽  
Copper Recovery ◽  
Copper Extraction ◽  
Efficient Technology ◽  
Flotation Tailings ◽  
Copper Mine ◽  
Moderately Thermophilic ◽  
Acidophilic Bacteria ◽  
Leaching Experiment ◽  
Optimal Technology

This work aimed to investigate optimal leaching technology for copper extraction from old flotation tailings of the Copper Mine Bor. The leaching degree of copper after leaching with sulphuric acid at 80 °C was 50%, the maximal leaching degree was achieved after 30 minutes. Then, old flotation tailings were leached with adapted moderately thermophilic acidophilic bacteria in a bioreactor at 40 °C. Maximal leaching degree of 84% was achieved after nine days of the experiment. The third leaching experiment was conducted with biogenic lixiviant obtained by bacterial oxidation of the ferrous iron (concentration of Fe3+ 1300 mgL-1, pH 2.14). Biogenic lixiviant with ferric sulphate was then used in the leaching experiment at 80 °C. Maximal leaching degree was 78%, and it was achieved after five minutes. Results of the leaching experiments show that the most efficient technology for copper recovery from the old flotation tailings of the Copper Mine Bor was leaching with biogenic lixiviant.

Application Potential of Biohydrometallurgy in the Iranian Mining Industry

2007 ◽  
Vol 20-21 ◽  
pp. 38-41 ◽  
Author(s):  
M. Ranjbar ◽  
M. Schaffie ◽  
Mohammad Pazouki ◽  
R. Ghazi ◽  
A. Akbary ◽  
...  
Keyword(s):  
Mining Industry ◽  
Copper Recovery ◽  
Commercial Application ◽  
Copper Extraction ◽  
Low Grade ◽  
High Grade ◽  
Bacterial Leaching ◽  
Application Potential ◽  
Commercial Applications ◽  
Essential Growth

Several studies and different successful commercial applications had demonstrated that bioleaching can be an innovative approach that is capable to provide mining industry opportunities for essential growth in the medium term[2-18]. To identify the commercial application potential of bioleaching in Iranian copper industry, a research program was initiated. The objective of the main part of this program was to evaluate bacterial leaching processes for copper recovery from (i) high grade ores and flotation concentrates and (ii) low grade ores and flotation tailings. The latest results of these studies indicates the general operability of the bioleaching in both cases. At optimum conditions, the copper extraction from low grade materials was more than 80% and that from high grade ores and flotation concentrates about 95%, which should be high enough to justify the process economically.

Advances in Tank Bioleaching of Low-Grade Chalcopyrite Concentrates

2009 ◽  
Vol 71-73 ◽  
pp. 361-364 ◽  
Author(s):  
Mariekie Gericke ◽  
Y. Govender ◽  
A. Pinches
Keyword(s):  
Redox Potential ◽  
Control Strategies ◽  
Operating Conditions ◽  
Low Grade ◽  
Bench Scale ◽  
Multi Stage ◽  
Moderate Thermophile ◽  
And Control ◽  
Potential Conditions

The focus of this paper is on the treatment of low-grade chalcopyrite-pyrite containing concentrates. The bioleaching of chalcopyrite is a major challenge due to slow copper leach kinetics and poor copper extractions. Bioleaching tests were carried out in bench-scale piloting facilities, comprising fully controlled multi-stage continuously operated reactor systems using moderate thermophile and thermophile consortia under both uncontrolled and controlled redox potential conditions. Bioleaching operating conditions and control strategies have been identified, which have the potential to significantly increase the rate of Cu leaching and to reduce process costs by allowing control of the amount of pyrite oxidised.

scholarly journals Cancer Related Anemia: An Integrated Multitarget Approach and Lifestyle Interventions

Nutrients ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 482
Author(s):  
Valentina Natalucci ◽  
Edy Virgili ◽  
Federica Calcagnoli ◽  
Giacomo Valli ◽  
Deborah Agostini ◽  
...  
Keyword(s):  
Iron Homeostasis ◽  
Iron Concentration ◽  
Transferrin Saturation ◽  
Intravenous Iron ◽  
Complex Problem ◽  
Low Grade ◽  
Inflammatory Status ◽  
Line Of Therapy ◽  
Cancer Related Anemia ◽  
Low Grade Inflammation

Cancer is often accompanied by worsening of the patient’s iron profile, and the resulting anemia could be a factor that negatively impacts antineoplastic treatment efficacy and patient survival. The first line of therapy is usually based on oral or intravenous iron supplementation; however, many patients remain anemic and do not respond. The key might lie in the pathogenesis of the anemia itself. Cancer-related anemia (CRA) is characterized by a decreased circulating serum iron concentration and transferrin saturation despite ample iron stores, pointing to a more complex problem related to iron homeostatic regulation and additional factors such as chronic inflammatory status. This review explores our current understanding of iron homeostasis in cancer, shedding light on the modulatory role of hepcidin in intestinal iron absorption, iron recycling, mobilization from liver deposits, and inducible regulators by infections and inflammation. The underlying relationship between CRA and systemic low-grade inflammation will be discussed, and an integrated multitarget approach based on nutrition and exercise to improve iron utilization by reducing low-grade inflammation, modulating the immune response, and supporting antioxidant mechanisms will also be proposed. Indeed, a Mediterranean-based diet, nutritional supplements and exercise are suggested as potential individualized strategies and as a complementary approach to conventional CRA therapy.

scholarly journals Increased Plasma Ferritin Concentration and Low-Grade Inflammation—A Mendelian Randomization Study

2018 ◽  
Vol 64 (2) ◽  
pp. 374-385 ◽  
Author(s):  
Ingrid W Moen ◽  
Helle K M Bergholdt ◽  
Thomas Mandrup-Poulsen ◽  
Børge G Nordestgaard ◽  
Christina Ellervik
Keyword(s):  
Odds Ratio ◽  
Mendelian Randomization ◽  
Iron Concentration ◽  
Complement C3 ◽  
Incomplete Penetrance ◽  
Low Grade ◽  
Ferritin Concentration ◽  
Mediation Analyses ◽  
All Cause Mortality ◽  
Low Grade Inflammation

Abstract BACKGROUND It is unknown why increased plasma ferritin concentration predicts all-cause mortality. As low-grade inflammation and increased plasma ferritin concentration are associated with all-cause mortality, we hypothesized that increased plasma ferritin concentration is genetically associated with low-grade inflammation. METHODS We investigated whether increased plasma ferritin concentration is associated with low-grade inflammation [i.e., increased concentrations of C-reactive protein (CRP) and complement component 3 (C3)] in 62537 individuals from the Danish general population. We also applied a Mendelian randomization approach, using the hemochromatosis genotype C282Y/C282Y as an instrument for increased plasma ferritin concentration, to assess causality. RESULTS For a doubling in plasma ferritin concentration, the odds ratio (95% CI) for CRP ≥2 vs <2 mg/L was 1.12 (1.09–1.16), with a corresponding genetic estimate for C282Y/C282Y of 1.03 (1.01–1.06). For a doubling in plasma ferritin concentration, odds ratio (95% CI) for complement C3 >1.04 vs ≤1.04 g/L was 1.28 (1.21–1.35), and the corresponding genetic estimate for C282Y/C282Y was 1.06 (1.03–1.12). Mediation analyses showed that 74% (95% CI, 24–123) of the association of C282Y/C282Y with risk of increased CRP and 56% (17%–96%) of the association of C282Y/C282Y with risk of increased complement C3 were mediated through plasma ferritin concentration. CONCLUSIONS Increased plasma ferritin concentration as a marker of increased iron concentration is associated observationally and genetically with low-grade inflammation, possibly indicating a causal relationship from increased ferritin to inflammation. However, as HFE may also play an immunological role indicating pleiotropy and as incomplete penetrance of C282Y/C282Y indicates buffering mechanisms, these weaknesses in the study design could bias the genetic estimates.

A Parametric Examination of the Factors Affecting the Performance of a Diffusion Absorption Refrigeration System

2021 ◽  
pp. 1-38
Author(s):  
Noman Yousuf ◽  
Timothy Anderson ◽  
Roy Nates
Keyword(s):  
Waste Heat ◽  
Operating Conditions ◽  
Design Parameters ◽  
Working Fluid ◽  
Low Grade ◽  
Absorption Refrigeration ◽  
Factors Affecting ◽  
Thermally Driven ◽  
Mass Flowrate ◽  
Diffusion Absorption

Abstract Despite being identified nearly a century ago, the diffusion absorption refrigeration (DAR) cycle has received relatively little attention. One of the strongest attractions of the DAR cycle lies in the fact that it is thermally driven and does not require high value work. This makes it a prime candidate for harnessing low grade heat from solar collectors, or the waste heat from stationary generators, to produce cooling. However, to realize the benefits of the DAR cycle, there is a need to develop an improved understanding of how design parameters influence its performance. In this vein, this work developed a new parametric model that can be used to examine the performance of the DAR cycle for a range of operating conditions. The results showed that the cycle's performance was particularly sensitive to several factors: the rate of heat added and the temperature of the generator, the effectiveness of the gas and solution heat exchangers, the mass flowrate of the refrigerant and the type of the working fluid. It was shown that can deliver good performance at low generator temperatures if the refrigerant mass fraction in the strong solution is made as high as possible. Moreover, it was shown that a H2O-LiBr working pair could be useful for achieving cooling at low generator temperatures.

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