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.

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.

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.

scholarly journals The Effects of Sulphuric Acid and Sodium Chloride Agglomeration and Curing on Chalcopyrite Leaching

Metals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 873
Author(s):  
Víctor Quezada ◽  
Antoni Roca ◽  
Oscar Benavente ◽  
Montserrat Cruells ◽  
Evelyn Melo
Keyword(s):  
Sodium Chloride ◽  
Sulphuric Acid ◽  
Copper Extraction ◽  
Curing Time ◽  
X Ray Diffraction ◽  
Sulphide Ores ◽  
Reflected Light ◽  
Copper Leaching ◽  
Kinetics Of ◽  
Leaching Efficiency

An option to improve the leaching efficiency of chalcopyrite is pretreatment prior to leaching. Pretreatment variables, such as the curing time and the addition of chloride, can increase the kinetics of copper extraction, particularly for sulphide ores. However, there has been little research on the topic. The reactions that govern this phenomenon have not been clearly identified. In this study, the effects of sulphuric acid and sodium chloride agglomeration and curing on chalcopyrite leaching were evaluated at various temperatures: 25, 50, 70, and 90 °C. The pretreated ore and leach residues were characterised by X-ray diffraction, scanning electron microscopy, and reflected light microscopy. Under the conditions of 15 kg/t of H2SO4, 25 kg/t of NaCl, and 15 days of curing time (as pretreatment), the following products were identified: CuSO4, NaFe3(SO4)2(OH)6, Cu2Cl(OH), and S0. Increasing the curing time and leaching temperature increased copper leaching. The copper extraction was 94% when leaching at 90 °C after pretreatment with 50 g/L of Cl- and 0.2 M of H2SO4. Elemental sulphur, jarosite, and copper polysulphide (CuS2) were detected in the leaching residues.

Control of biological iron removal from drinking water using oxidation-reduction potential

1998 ◽  
Vol 38 (6) ◽  
pp. 121-128 ◽  
Author(s):  
Catherine V. Tremblay ◽  
André Beaubien ◽  
Philippe Charles ◽  
James A. Nicell
Keyword(s):  
Drinking Water ◽  
Pilot Plant ◽  
Reduction Potential ◽  
Iron Concentration ◽  
Operating Conditions ◽  
Industrial Plant ◽  
Filtration Cycle ◽  
Biological Removal ◽  
Oxidation Reduction ◽  
Oxidation Reduction Potential

Biological removal of iron to produce drinking water was established in a pilot plant treating raw water with a pH of 5.7. The objective was to evaluate the use of oxidation-reduction potential (ORP) as a control tool and determine its relationship to dissolved oxygen (DO) and residual iron concentration in filtered water from an operating biological filter. Results showed that above a low minimum value of DO, residual iron concentration and ORP were not affected by varying the DO level. A non-linear regression was established to correlate total residual iron concentration to ORP with an R2 of 0.8848. This correlation can be used to predict iron concentration when ORP is in the range 300 to 470 mV. Below this range, total residual iron is greater than or equal to 3 mg/l and above, total residual iron is less than the French regulation limit of 0.2 mg/l. Pilot plant operating conditions were implemented in the primary filter of an industrial plant in France, improving iron elimination and doubling the length of the filtration cycle.

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.

scholarly journals Effect of Ultrasound on the Oxidative Copper Leaching from Chalcopyrite in Acidic Ferric Sulfate Media

Minerals ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 633
Author(s):  
Jingxiu Wang ◽  
Fariborz Faraji ◽  
Ahmad Ghahreman
Keyword(s):  
Acid Concentration ◽  
Ultrasonic Waves ◽  
Ferric Sulfate ◽  
Copper Recovery ◽  
Copper Extraction ◽  
Ultrasonic Power ◽  
Leaching Rate ◽  
X Ray ◽  
Copper Leaching ◽  
Significant Difference

The objective of this study is to compare the reaction kinetics of copper leaching from chalcopyrite in acidic ferric sulfate media with (UAL) and without (non-UAL) ultrasound assistance. Four leaching parameters were evaluated and optimized. The parameter with the strongest effect was temperature, followed by ultrasonic power, the solid-to-liquid ratio (S/L), and acid concentration. Copper recovery showed an increase with rising temperatures in both systems. Ultrasonic power had a positive effect on copper leaching, but no significant difference was found among various power amplitudes. Copper extraction increased with decreasing S/L. At 0.1% S/L, the UAL leaching rate was double the non-UAL leaching rate. In both systems, acid concentration had little effect on copper extraction. Under optimized conditions, 20% amplitude power, 1% S/L, 0.5 M acid, and 80 °C leaching temperature, copper extraction was 50.4% and 57.5% in the non-UAL and UAL treatments, respectively. Ultrasonic waves enhanced the leaching rate, shortened the reaction time, and reduced acid consumption. Analysis of the rate-controlling step using a shrinking core model showed that leaching occurs after diffusion through the product layer but also chemical controlled in both non-UAL and UAL systems. The leaching mechanism was confirmed by characterizing the chalcopyrite and leached residue with X-ray diffraction and scanning electron microscopy/energy dispersive X-ray spectroscopy.

scholarly journals Use of Simulator for Decision to Reuse of Industrial Effluents

2021 ◽  
Vol 15 ◽  
pp. 22-26
Author(s):  
Ana Cecilia Correia dos Santos ◽  
Elias Andrade Braga ◽  
Igor L. S. Rodrigues ◽  
Ricardo de Araϊjo Kalid ◽  
Asher Kiperstok
Keyword(s):  
Water Reuse ◽  
Iron Concentration ◽  
Industrial Effluents ◽  
Experimental Tests ◽  
Additional Treatment ◽  
Operating Conditions ◽  
Saturated Steam ◽  
Industrial Plant ◽  
High Concentration ◽  
Water And Wastewater Treatment

The need to reduce operational inefficiency because no generation of effluent encourages industries to search improvements in the procedures and technologies. However, in case that is not technically or economically feasible, the water reuse is a good option. The removal of volatile organic compounds (VOC) in liquid streams at a nitrogen fertilizer industry is carried out in a stripper that generates treated condensate that can be reused. The present work aims at the reuse of the treated condensate to produce steam and it was conducted according to methodology: collection and reconciliation of data in the industrial plant; simulation operating conditions and changed conditions for the most contaminant removal; tests in loco and analysis of physicchemical parameters to assess the quality of the treated condensate. The simulation was performed in steady state for two scenarios: the first one using operating conditions with vapor pressure between 3.2 bar and 6.0 bar and a flow rate of saturated steam between 1.5 t/h 5.0 t/h; the second simulation scenery considered the removal of the D stream process of the stripper, that has a high concentration of ammonia and methanol. In the first scenario, it was observed by manipulating of the pressure to 6.0 bar and steam flow to 2.0 t/h make better the removal ammonia efficiency. For the second scenario has also greater efficiency in the removal of both ammonia and methanol. The tests in loco and physic-chemical analysis showed that removal of the D stream process can enable the of reuse to make up for water in boiler to produce steam of until 41 bar after additional treatment, reducing the conductivity and iron concentration. The reuse of this treated condensate provides an economic gain of approximately US$ 500 000 each year, reducing the cost with the use of demineralized water and wastewater treatment. The use of the simulator allowed studying different scenarios, to reduce the number of experimental tests in loco and establishing routes for reuse industrial wastewater.

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 Leaching of Chalcopyrite under Bacteria–Mineral Contact/Noncontact Leaching Model

Minerals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 230
Author(s):  
Pengcheng Ma ◽  
Hongying Yang ◽  
Zuochun Luan ◽  
Qifei Sun ◽  
Auwalu Ali ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Surface Passivation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Leaching Process ◽  
Copper Leaching ◽  
Hydrolysis Of ◽  
Leaching Efficiency ◽  
Leaching Models ◽  
Scanning Electron

Bacteria–mineral contact and noncontact leaching models coexist in the bioleaching process. In the present paper, dialysis bags were used to study the bioleaching process by separating the bacteria from the mineral, and the reasons for chalcopyrite surface passivation were discussed. The results show that the copper leaching efficiency of the bacteria–mineral contact model was higher than that of the bacteria–mineral noncontact model. Scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier-transform infrared (FTIR) were used to discover that the leaching process led to the formation of a sulfur film to inhibit the diffusion of reactive ions. In addition, the deposited jarosite on chalcopyrite surface was crystallized by the hydrolysis of the excess Fe3+ ions. The depositions passivated the chalcopyrite leaching process. The crystallized jarosite in the bacteria EPS layer belonged to bacteria–mineral contact leaching system, while that in the sulfur films belonged to the bacteria–mineral noncontact system.

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.

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