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Jun Wang - One of the best experts on this subject based on the ideXlab platform.
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comparison of leaching of Bornite from different regions mediated by mixed moderately thermophilic bacteria
Journal of Central South University, 2020Co-Authors: Zhihua Huang, Jun Wang, Kexin Chang, Yansheng ZhangAbstract:Bioleaching experiments combined with X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and scanning electron microscopy (SEM) were conducted to investigate three kinds of Bornites from different regions leached by moderately thermophilic mixed bacteria of Leptospirillum ferriphilum YSK, Acidithiobacillus caldus D1 and Sulfobacillus thermosulfidooxidans ST. The results of bioleaching experiments showed that the leaching efficiency and the redox potential were significantly increased. The copper extraction efficiencies of three kinds of Bornite maintained rapid growth until around the 12th day and no longer increased after the 18th reaching 83.7%, 96.5% and 86.6%, respectively. The XRD results of the leaching residue indicated that three kinds of Bornites all produced jarosite in the late stage of leaching, and the leaching residues from of Daye Museum and Yunnan Geological Museum contained a mass of elemental sulfur. XPS analysis and scanning electron microscopy experiments showed that the surface of mineral particles was jarosite and the copper in the leaching residue was almost dissolved.
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Intermediates Transformation of Bornite Bioleaching by Leptospirillum ferriphilum and Acidithiobacillus caldus
Minerals, 2019Co-Authors: Maoxin Hong, Xiaotao Huang, Rui Liao, Xingxing Wang, Chaojun Fang, Jun WangAbstract:Bioleaching experiments, electrochemical tests, X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) were conducted to investigate the intermediates transformation of Bornite by Leptospirillum ferriphilum and Acidithiobacillus caldus. The bioleaching experimental results showed that the presence of L. ferriphilum and A. caldus significantly accelerated the Bornite bioleaching. In addition, the intermediate species of Bornite bioleaching with these two kinds of bacteria were similar. Electrochemical analysis indicated that the dissolution of Bornite was an acid-consuming process. The results of XRD showed that intermediate species, namely covellite (CuS), mooihoekit (Cu9Fe9S16) and isocubanite (CuFe2S3), were formed during Bornite bioleaching, and a mass of elemental sulfur was formed in the late stage of bioleaching. The Cu 2p photoelectron spectrum revealed that Cu was present in the form of Cu (I) during the Bornite bioleaching. Additionally, the S 2p3/2 photoelectron spectrum suggested that S2− and S22− were gradually converted to Sn2−/S0, and the formation of elemental sulfur hindered the further dissolution of the Bornite.
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synergetic effect of pyrite on strengthening Bornite bioleaching by leptospirillum ferriphilum
Hydrometallurgy, 2018Co-Authors: Xingxing Wang, Maoxing Hong, Caoming Huang, Xiaotao Huang, Rui Liao, Hong Peng, Jun WangAbstract:Abstract Bioleaching experiments and electrochemical measurements were conducted to investigate the effect of pyrite on Bornite bioleaching by Leptospirillum ferriphilum. Bioleaching experiments results showed that the addition of pyrite increased the redox potential to 360 mV vs. an Ag/AgCl electrode in the initial period of bioleaching process. The presence of pyrite significantly increased the copper extraction efficiency to 95.9% while the extraction value was only 19% without pyrite addition after 20 days. Furthermore, the addition of pyrite also decreased the consumption of acid during bioleaching of Bornite. Especially, the total acid consumption was only 0.002 mmol at a pyrite to Bornite ratio of 5:1 while the value was 2.842 mmol without pyrite addition. The results of electrochemical experiments identified that a galvanic effect existed between Bornite and pyrite, and Bornite was more prone to oxidation sand reduction. Tafel plot and galvanic corrosion tests indicated that the addition of pyrite accelerated the dissolution of Bornite. Furthermore, the dissolution of Bornite with pyrite additon was not inhibited by the formation of element sulfur and jarosite that may lead to passivation of chalcopyrite bioleaching. Based on all the observations, a mechanism model on how pyrite accelerated Bornite dissolution is proposed.
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bioleaching of chalcopyrite and Bornite by moderately thermophilic bacteria an emphasis on their interactions
International Journal of Minerals Metallurgy and Materials, 2015Co-Authors: Minghao Hu, Jun WangAbstract:Interactions between chalcopyrite and Bornite during bioleaching by moderately thermophilic bacteria were investigated mainly by X-ray diffraction, scanning electron microscopy, and electrochemical measurements performed in conjunction with bioleaching experiments. The results showed that a synergistic effect existed between chalcopyrite and Bornite during bioleaching by both Acidithiobacillus caldus and Leptospirillum ferriphilum and that extremely high copper extraction could be achieved when chalcopyrite and Bornite coexisted in a bioleaching system. Bornite dissolved preferentially because of its lower corrosion potential, and its dissolution was accelerated by the galvanic current during the initial stage of bioleaching. The galvanic current and optimum redox potential of 390−480 mV vs. Ag/AgCl promoted the reduction of chalcopyrite to chalcocite (Cu2S), thus accelerating its dissolution.
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Effects of pyrite and Bornite on bioleaching of two different types of chalcopyrite in the presence of Leptospirillum ferriphilum
Bioresource technology, 2015Co-Authors: Jun Wang, Xihua Zheng, Wenqing Qin, Xiaowen Gan, Lang Tao, Guanzhou QiuAbstract:The effects of pyrite and Bornite on bioleaching of two different chalcopyrite samples by Leptospirillum ferriphilum were studied for the first time. Results showed that bioleaching behaviors of the two chalcopyrite samples were extremely different. Bornite decreased the redox potential (ORP) and maintained it at an appropriate range (380-480 mV vs. Ag/AgCl) to promote chalcopyrite (A) dissolution, but caused the redox potential out of the optimum range and inhibited chalcopyrite (B) dissolution. Large amount of pyrite decreased the redox potential and maintained it at an optimum range to promote chalcopyrite (A) dissolution, while increased the redox potential and kept it at appropriate range for a longer period of time to enhance the dissolution rate of chalcopyrite (B). Chalcopyrite (B) had significantly higher values of conductivity and oxidation-reduction rate when compared with those of chalcopyrite (A). The work is potentially useful in interpreting the inconsistence of the researches of chalcopyrite hydrometallurgy.
Grigore Simon - One of the best experts on this subject based on the ideXlab platform.
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gold in porphyry copper deposits its abundance and fate
Ore Geology Reviews, 2002Co-Authors: Stephen E. Kesler, Stephen L Chryssoulis, Grigore SimonAbstract:Abstract Porphyry copper deposits are among the largest reservoirs of gold in the upper crust and are important potential sources for gold in lower temperature epithermal deposits. Whether gold remains in porphyry copper deposits is important both to their economic attractiveness and to the distribution of gold in the upper crust. Cu/Au atomic ratios of porphyry copper ore deposits form a continuous range from about 5000 to 5,000,000 with a median near 40,000, which separates gold-rich and gold-poor deposits. Gold is found in porphyry copper deposits in solid solution in Cu–Fe and Cu sulfides and as small grains of native gold, usually along boundaries of Bornite. SIMS (ion probe) analyses of ore minerals from the gold-rich Batu Hijau, Kingking and Skouries porphyry copper deposits show that Bornite contains about 1 ppm Au, whereas chalcopyrite contains about an order of magnitude less. Chalcocite and covellite contain 10–20 ppm Au, but are not abundant enough to account for a significant part of the gold endowment in many porphyry copper deposits. The amount of gold presently in solid solution in Cu–Fe sulfides is not adequate to account for all the gold in porphyry copper deposits, and the remainder is present as micron-scale grains of native gold. Experiments in the Cu–Fe–S–Au system show that Bornite and chalcopyrite can contain about 1000 ppm gold at typical porphyry copper formation temperatures of 600–700°C, and indicate that Bornite and chalcopyrite in porphyry copper deposits were saturated with respect to gold at temperatures of only 200–300°C. In contrast, Cu/Au ratios of bulk ore in porphyry copper deposits would require Bornite and chalcopyrite to be saturated with respect to gold at temperatures similar to those at which primary (potassic) ore and alteration are thought to form. This indicates that the maximum gold endowment of porphyry copper deposits is probably fixed by the amount of gold that will go into solid solution in Cu–Fe sulfides when the deposit forms at high temperature, and that gold is not commonly added later from other sources, although it can be redistributed during cooling or later events. The experimental data also suggest that high-temperature (600–700°C) vapors can extract considerably more gold from porphyry copper systems than can low-temperature (300°C) alteration. Comparison to Cu/Au ratios of volcanic emissions suggests further that high-temperature processes remove copper (relative to gold) from porphyry copper systems, whereas low-temperature processes remove gold preferentially and that this can account for deposits with extremely low and high Cu/Au ratios, respectively. Deposits with Cu/Au ratios between about 20,000 and 100,000, however, probably reflect different degrees of removal of gold or copper by immiscible sulfides.
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gold in porphyry copper deposits experimental determination of the distribution of gold in the cu fe s system at 400 to 700 c
Economic Geology, 2000Co-Authors: Grigore Simon, Eric J. Essene, Stephen E. Kesler, Stephen L ChryssoulisAbstract:Experiments in the system Au-Cu-Fe-S were carried out at temperatures of 400° to 700°C to determine how much gold could be accommodated by Bornite and chalcopyrite, the two most common ore minerals in porphyry copper-gold deposits. Our results show that for all temperatures Bornite contains one order of magnitude more gold than chalcopyrite (or intermediate solid solution (iss), its high-temperature equivalent). The range of gold concentrations in Bornite and chalcopyrite (or iss) decreases with decreasing temperature from 1,280 to 8,200 ppm Au in Bornite and 100 to 125 ppm Au in iss at 600°C, to 235 to 364 ppm Au in Bornite and 5 to 16 ppm Au in chalcopyrite (or iss) at 500°C, and to 13 to 80 ppm Au in Bornite and 2 to 4 ppm Au in chalcopyrite (or iss) at 400°C. The amount of gold in Bornite is also strongly dependent on the composition of Bornite, being highest in "stoichiometric" Bornite compositions (Cu5FeS4), and decreasing toward Cu-rich and Cu-poor compositions. Phase equilibrium constraints for solutions with geologically reasonable reduced sulfur contents indicate that high-temperature porphyry copper-gold deposits will contain Bornite and magnetite, whereas lower temperature deposits (whether primary or overprinted by phyllic alteration) will contain chalcopyrite and pyrite. If gold is present in the ore-forming solutions, more of it will be deposited in high-temperature porphyry copper-gold deposits where it will be closely associated with Bornite. Coexisting magnetite in these deposits should generate magnetic anomalies. Lower temperature deposits will contain less gold, which is hosted by pyrite as well as chalcopyrite, and will lack magnetic anomalies. Comparison of the amount of gold hosted by natural porphyry copper-gold ores to that hosted by Bornite and chalcopyrite in our experiments suggests that significant amounts of gold can be lost from these deposits into surrounding hydrothermal systems.
Stephen E. Kesler - One of the best experts on this subject based on the ideXlab platform.
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unusually cu rich magmas associated with giant porphyry copper deposits evidence from bingham utah
Geology, 2006Co-Authors: Daniel P Core, Stephen E. Kesler, Eric J. EsseneAbstract:Mass-balance constraints indicate that formation of giant porphyry copper deposits (PCDs) requires either highly efficient collection of Cu from large volumes of magma or unusually Cu-rich parent magmas. Support for the second of these possibilities has been discovered in the form of mafic enclaves with abundant Bornite and chalcopyrite in the Last Chance stock, one of the parent intrusions of the giant Bingham PCD, Utah, United States. Mineral assemblages and compositions indicate that the Last Chance enclaves are autoliths consisting of phases that crystallized from the intrusion, and that the intrusion was unusually enriched in Cu. One possible mechanism for generating Cu-rich magmas is fractional crystallization during pyrrhotite undersaturated conditions. The high fO 2 conditions observed for the Last Chance stock may have allowed such an evolution. Alternatively, if the magma has not undergone significant fractionation, early crystallization of chalcopyrite and Bornite from the magma would indicate that the lower-crustal source region for the magma probably contained Cu-Fe sulfides. Possible Cu-rich source regions are a subcrustal mafic intrusion with sulfide cumulates, or a deeply buried metamorphic terrane containing Cu deposits such as those in the Curaca Valley (Brazil) or Okiep (South Africa). Heterogeneous distribution of Cu-Fe sulfides in an Okiep-type source terrane would produce local PCDs such as Bingham, or large accumulations of Cu-Fe sulfides, possibly in the form of cumulates in subcrustal intrusions at convergent margins, could produce giant PCD provinces such as those in Indonesia, Papua New Guinea, and central Chile.
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gold in porphyry copper deposits its abundance and fate
Ore Geology Reviews, 2002Co-Authors: Stephen E. Kesler, Stephen L Chryssoulis, Grigore SimonAbstract:Abstract Porphyry copper deposits are among the largest reservoirs of gold in the upper crust and are important potential sources for gold in lower temperature epithermal deposits. Whether gold remains in porphyry copper deposits is important both to their economic attractiveness and to the distribution of gold in the upper crust. Cu/Au atomic ratios of porphyry copper ore deposits form a continuous range from about 5000 to 5,000,000 with a median near 40,000, which separates gold-rich and gold-poor deposits. Gold is found in porphyry copper deposits in solid solution in Cu–Fe and Cu sulfides and as small grains of native gold, usually along boundaries of Bornite. SIMS (ion probe) analyses of ore minerals from the gold-rich Batu Hijau, Kingking and Skouries porphyry copper deposits show that Bornite contains about 1 ppm Au, whereas chalcopyrite contains about an order of magnitude less. Chalcocite and covellite contain 10–20 ppm Au, but are not abundant enough to account for a significant part of the gold endowment in many porphyry copper deposits. The amount of gold presently in solid solution in Cu–Fe sulfides is not adequate to account for all the gold in porphyry copper deposits, and the remainder is present as micron-scale grains of native gold. Experiments in the Cu–Fe–S–Au system show that Bornite and chalcopyrite can contain about 1000 ppm gold at typical porphyry copper formation temperatures of 600–700°C, and indicate that Bornite and chalcopyrite in porphyry copper deposits were saturated with respect to gold at temperatures of only 200–300°C. In contrast, Cu/Au ratios of bulk ore in porphyry copper deposits would require Bornite and chalcopyrite to be saturated with respect to gold at temperatures similar to those at which primary (potassic) ore and alteration are thought to form. This indicates that the maximum gold endowment of porphyry copper deposits is probably fixed by the amount of gold that will go into solid solution in Cu–Fe sulfides when the deposit forms at high temperature, and that gold is not commonly added later from other sources, although it can be redistributed during cooling or later events. The experimental data also suggest that high-temperature (600–700°C) vapors can extract considerably more gold from porphyry copper systems than can low-temperature (300°C) alteration. Comparison to Cu/Au ratios of volcanic emissions suggests further that high-temperature processes remove copper (relative to gold) from porphyry copper systems, whereas low-temperature processes remove gold preferentially and that this can account for deposits with extremely low and high Cu/Au ratios, respectively. Deposits with Cu/Au ratios between about 20,000 and 100,000, however, probably reflect different degrees of removal of gold or copper by immiscible sulfides.
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gold in porphyry copper deposits experimental determination of the distribution of gold in the cu fe s system at 400 to 700 c
Economic Geology, 2000Co-Authors: Grigore Simon, Eric J. Essene, Stephen E. Kesler, Stephen L ChryssoulisAbstract:Experiments in the system Au-Cu-Fe-S were carried out at temperatures of 400° to 700°C to determine how much gold could be accommodated by Bornite and chalcopyrite, the two most common ore minerals in porphyry copper-gold deposits. Our results show that for all temperatures Bornite contains one order of magnitude more gold than chalcopyrite (or intermediate solid solution (iss), its high-temperature equivalent). The range of gold concentrations in Bornite and chalcopyrite (or iss) decreases with decreasing temperature from 1,280 to 8,200 ppm Au in Bornite and 100 to 125 ppm Au in iss at 600°C, to 235 to 364 ppm Au in Bornite and 5 to 16 ppm Au in chalcopyrite (or iss) at 500°C, and to 13 to 80 ppm Au in Bornite and 2 to 4 ppm Au in chalcopyrite (or iss) at 400°C. The amount of gold in Bornite is also strongly dependent on the composition of Bornite, being highest in "stoichiometric" Bornite compositions (Cu5FeS4), and decreasing toward Cu-rich and Cu-poor compositions. Phase equilibrium constraints for solutions with geologically reasonable reduced sulfur contents indicate that high-temperature porphyry copper-gold deposits will contain Bornite and magnetite, whereas lower temperature deposits (whether primary or overprinted by phyllic alteration) will contain chalcopyrite and pyrite. If gold is present in the ore-forming solutions, more of it will be deposited in high-temperature porphyry copper-gold deposits where it will be closely associated with Bornite. Coexisting magnetite in these deposits should generate magnetic anomalies. Lower temperature deposits will contain less gold, which is hosted by pyrite as well as chalcopyrite, and will lack magnetic anomalies. Comparison of the amount of gold hosted by natural porphyry copper-gold ores to that hosted by Bornite and chalcopyrite in our experiments suggests that significant amounts of gold can be lost from these deposits into surrounding hydrothermal systems.
Yansheng Zhang - One of the best experts on this subject based on the ideXlab platform.
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comparison of leaching of Bornite from different regions mediated by mixed moderately thermophilic bacteria
Journal of Central South University, 2020Co-Authors: Zhihua Huang, Jun Wang, Kexin Chang, Yansheng ZhangAbstract:Bioleaching experiments combined with X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and scanning electron microscopy (SEM) were conducted to investigate three kinds of Bornites from different regions leached by moderately thermophilic mixed bacteria of Leptospirillum ferriphilum YSK, Acidithiobacillus caldus D1 and Sulfobacillus thermosulfidooxidans ST. The results of bioleaching experiments showed that the leaching efficiency and the redox potential were significantly increased. The copper extraction efficiencies of three kinds of Bornite maintained rapid growth until around the 12th day and no longer increased after the 18th reaching 83.7%, 96.5% and 86.6%, respectively. The XRD results of the leaching residue indicated that three kinds of Bornites all produced jarosite in the late stage of leaching, and the leaching residues from of Daye Museum and Yunnan Geological Museum contained a mass of elemental sulfur. XPS analysis and scanning electron microscopy experiments showed that the surface of mineral particles was jarosite and the copper in the leaching residue was almost dissolved.
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synergistic bioleaching of chalcopyrite and Bornite in the presence of acidithiobacillus ferrooxidans
Bioresource Technology, 2013Co-Authors: Jun Wang, Yansheng Zhang, Wenqing QinAbstract:Bioleaching of chalcopyrite and Bornite in the presence of Acidithiobacillus ferrooxidans was carried out to investigate the influences between each other during bioleaching. Bioleaching results indicated that Bornite accelerated the dissolution of chalcopyrite, and chalcopyrite also accelerated the dissolution of Bornite, it could be described as a synergistic effect during bioleaching, this synergistic effect might be attributed to the galvanic effect between chalcopyrite and Bornite, and to the relatively low solution potential as the addition of Bornite. Significantly amount of elemental sulfur and jarosite formed on the minerals surface might be the main passivation film inhibiting the further dissolution, and the amount of elemental sulfur significantly increased with the addition of Bornite. Results of electrochemical measurements indicated that the oxidation and reduction mechanisms of chalcopyrite and Bornite were similar, the addition of Bornite or chalcopyrite did not change the oxidative and reductive mechanisms, but increased the oxidation rate.
Stephen L Chryssoulis - One of the best experts on this subject based on the ideXlab platform.
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gold in porphyry copper deposits its abundance and fate
Ore Geology Reviews, 2002Co-Authors: Stephen E. Kesler, Stephen L Chryssoulis, Grigore SimonAbstract:Abstract Porphyry copper deposits are among the largest reservoirs of gold in the upper crust and are important potential sources for gold in lower temperature epithermal deposits. Whether gold remains in porphyry copper deposits is important both to their economic attractiveness and to the distribution of gold in the upper crust. Cu/Au atomic ratios of porphyry copper ore deposits form a continuous range from about 5000 to 5,000,000 with a median near 40,000, which separates gold-rich and gold-poor deposits. Gold is found in porphyry copper deposits in solid solution in Cu–Fe and Cu sulfides and as small grains of native gold, usually along boundaries of Bornite. SIMS (ion probe) analyses of ore minerals from the gold-rich Batu Hijau, Kingking and Skouries porphyry copper deposits show that Bornite contains about 1 ppm Au, whereas chalcopyrite contains about an order of magnitude less. Chalcocite and covellite contain 10–20 ppm Au, but are not abundant enough to account for a significant part of the gold endowment in many porphyry copper deposits. The amount of gold presently in solid solution in Cu–Fe sulfides is not adequate to account for all the gold in porphyry copper deposits, and the remainder is present as micron-scale grains of native gold. Experiments in the Cu–Fe–S–Au system show that Bornite and chalcopyrite can contain about 1000 ppm gold at typical porphyry copper formation temperatures of 600–700°C, and indicate that Bornite and chalcopyrite in porphyry copper deposits were saturated with respect to gold at temperatures of only 200–300°C. In contrast, Cu/Au ratios of bulk ore in porphyry copper deposits would require Bornite and chalcopyrite to be saturated with respect to gold at temperatures similar to those at which primary (potassic) ore and alteration are thought to form. This indicates that the maximum gold endowment of porphyry copper deposits is probably fixed by the amount of gold that will go into solid solution in Cu–Fe sulfides when the deposit forms at high temperature, and that gold is not commonly added later from other sources, although it can be redistributed during cooling or later events. The experimental data also suggest that high-temperature (600–700°C) vapors can extract considerably more gold from porphyry copper systems than can low-temperature (300°C) alteration. Comparison to Cu/Au ratios of volcanic emissions suggests further that high-temperature processes remove copper (relative to gold) from porphyry copper systems, whereas low-temperature processes remove gold preferentially and that this can account for deposits with extremely low and high Cu/Au ratios, respectively. Deposits with Cu/Au ratios between about 20,000 and 100,000, however, probably reflect different degrees of removal of gold or copper by immiscible sulfides.
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gold in porphyry copper deposits experimental determination of the distribution of gold in the cu fe s system at 400 to 700 c
Economic Geology, 2000Co-Authors: Grigore Simon, Eric J. Essene, Stephen E. Kesler, Stephen L ChryssoulisAbstract:Experiments in the system Au-Cu-Fe-S were carried out at temperatures of 400° to 700°C to determine how much gold could be accommodated by Bornite and chalcopyrite, the two most common ore minerals in porphyry copper-gold deposits. Our results show that for all temperatures Bornite contains one order of magnitude more gold than chalcopyrite (or intermediate solid solution (iss), its high-temperature equivalent). The range of gold concentrations in Bornite and chalcopyrite (or iss) decreases with decreasing temperature from 1,280 to 8,200 ppm Au in Bornite and 100 to 125 ppm Au in iss at 600°C, to 235 to 364 ppm Au in Bornite and 5 to 16 ppm Au in chalcopyrite (or iss) at 500°C, and to 13 to 80 ppm Au in Bornite and 2 to 4 ppm Au in chalcopyrite (or iss) at 400°C. The amount of gold in Bornite is also strongly dependent on the composition of Bornite, being highest in "stoichiometric" Bornite compositions (Cu5FeS4), and decreasing toward Cu-rich and Cu-poor compositions. Phase equilibrium constraints for solutions with geologically reasonable reduced sulfur contents indicate that high-temperature porphyry copper-gold deposits will contain Bornite and magnetite, whereas lower temperature deposits (whether primary or overprinted by phyllic alteration) will contain chalcopyrite and pyrite. If gold is present in the ore-forming solutions, more of it will be deposited in high-temperature porphyry copper-gold deposits where it will be closely associated with Bornite. Coexisting magnetite in these deposits should generate magnetic anomalies. Lower temperature deposits will contain less gold, which is hosted by pyrite as well as chalcopyrite, and will lack magnetic anomalies. Comparison of the amount of gold hosted by natural porphyry copper-gold ores to that hosted by Bornite and chalcopyrite in our experiments suggests that significant amounts of gold can be lost from these deposits into surrounding hydrothermal systems.