In this work,the bioleaching process of pyrite,chalcocite and covellite which were the main phase compositions for Zijin copper mineral was comprehensively studied.The influence parameters,such as leaching temperature...In this work,the bioleaching process of pyrite,chalcocite and covellite which were the main phase compositions for Zijin copper mineral was comprehensively studied.The influence parameters,such as leaching temperature,Fe^(3+)concentration,pH of solution and bacteria concentration were investigated.The leaching kinetics of the pyrite,chalcocite and covellite under the studied conditions was successfully modeled by an empirical diffusion-like equation,respectively.The apparent activity energy of pyrite leaching,chalcocite leaching(stage Ⅱ)and covellite leaching was calculated to be 69.29,65.02 and 84.97 kJ/mol,respectively.展开更多
Simulated heap bioleaching of low-grade high pyrite-bearing chalcocite ore was conducted at 40 °C with aeration of CO_2 and N_2.Ore samples were collected at day 43,64,85,106 and subjected to microbial community ...Simulated heap bioleaching of low-grade high pyrite-bearing chalcocite ore was conducted at 40 °C with aeration of CO_2 and N_2.Ore samples were collected at day 43,64,85,106 and subjected to microbial community analysis by 16S rRNA gene clone library.Phylogenetic analyses of 16S rDNA fragments revealed that the retrieved sequences are mainly related to genus Acidithiobacillus,Leptospirillum and Sulfobacillus.Aeration of CO_2 and N_2 significantly impacted the microbial community composition.When CO_2 was aerated,the proportion of genus Acidithiobacillus considerably increased,whereas the proportion of genus Leptospirillum and genus Sulfobacillus declined.However,with the aeration of N_2,the proportion of genus Acidithiobacillus and Leptospirillum increased,but genus Sulfobacillus decreased.When there was no aeration,the microbial community was similar to the inocula with the proportion of genus Leptospirillum mounted.These results indicated that the limitation of oxygen could change the bioleaching microbial community and the aeration of CO_2 and N_2 was favourable for the growth of sulfur-oxidizer(At.caldus) and iron-oxidizer(L.ferriphilum) respectively,which could be used for the regulation of microorganisms' role in mineral bioleaching.展开更多
Mixed microorganisms with elevated activity of chalcocite-leaching were screened by mutation methods. The original microorganisms collected from acid mine drainage of different sites were mixed and then treated with m...Mixed microorganisms with elevated activity of chalcocite-leaching were screened by mutation methods. The original microorganisms collected from acid mine drainage of different sites were mixed and then treated with mutagens NO2^- , diethyl sulfate （DES）, UV and their combinations, respectively. Five groups of mixed microorganisms with much stronger ore-leaching ability were obtained by screening on the leaching media. Among them, group E of mixed microorganisms （treated with 1% DES for 60 min） with the best perfonnance on chalcocite-leaching, increases the content of Cu^2＋ by 101.4% in 20 d of leaching compared with the control culture. In addition, group E is more tolerant to Cu^2＋ in media than the control without mutation treatment. Analysis for the diversity of microbial clones indicates that half of operational taxonomic units （OTUs） in group E are Acidithiobacillus ferrooxidans. These observations suggest that group E might have potentials for industrial application.展开更多
Many researchers found that the Fe2+together with less amount of Cu2+can accelerate the leaching of chalcopyrite.In this work,the leaching of chalcopyrite with Cu2+was investigated.The leaching residuals were examined...Many researchers found that the Fe2+together with less amount of Cu2+can accelerate the leaching of chalcopyrite.In this work,the leaching of chalcopyrite with Cu2+was investigated.The leaching residuals were examined by Raman spectroscopy.Based on the leaching experiments,the chemical equilibrium in solution was calculated using Visual MINTEQ.The results showed that the Fe in chalcopyrite lattice was replaced by Cu2+;therefore,the chalcopyrite transformed into covellite.Furthermore,the formation of chalcocite occurred when Fe2+and Fe3+were added to the solution containing Cu2+.The copper extraction increased with a decrease of the initial redox potential(or the ratio of Fe3+/Fe2+).展开更多
基金Project(51574036)supported by the National Natural Science Foundation of China。
文摘In this work,the bioleaching process of pyrite,chalcocite and covellite which were the main phase compositions for Zijin copper mineral was comprehensively studied.The influence parameters,such as leaching temperature,Fe^(3+)concentration,pH of solution and bacteria concentration were investigated.The leaching kinetics of the pyrite,chalcocite and covellite under the studied conditions was successfully modeled by an empirical diffusion-like equation,respectively.The apparent activity energy of pyrite leaching,chalcocite leaching(stage Ⅱ)and covellite leaching was calculated to be 69.29,65.02 and 84.97 kJ/mol,respectively.
基金Project(51404033)supported by the National Natural Science Foundation of ChinaProject(2010CB630905)supported by the National Basic Research Program of China
文摘Simulated heap bioleaching of low-grade high pyrite-bearing chalcocite ore was conducted at 40 °C with aeration of CO_2 and N_2.Ore samples were collected at day 43,64,85,106 and subjected to microbial community analysis by 16S rRNA gene clone library.Phylogenetic analyses of 16S rDNA fragments revealed that the retrieved sequences are mainly related to genus Acidithiobacillus,Leptospirillum and Sulfobacillus.Aeration of CO_2 and N_2 significantly impacted the microbial community composition.When CO_2 was aerated,the proportion of genus Acidithiobacillus considerably increased,whereas the proportion of genus Leptospirillum and genus Sulfobacillus declined.However,with the aeration of N_2,the proportion of genus Acidithiobacillus and Leptospirillum increased,but genus Sulfobacillus decreased.When there was no aeration,the microbial community was similar to the inocula with the proportion of genus Leptospirillum mounted.These results indicated that the limitation of oxygen could change the bioleaching microbial community and the aeration of CO_2 and N_2 was favourable for the growth of sulfur-oxidizer(At.caldus) and iron-oxidizer(L.ferriphilum) respectively,which could be used for the regulation of microorganisms' role in mineral bioleaching.
基金Project(50321402)supported by the National Natural Science Foundation of ChinaProject(2004CB619201)supported by the Major State Basic Research and Development Program of China
文摘Mixed microorganisms with elevated activity of chalcocite-leaching were screened by mutation methods. The original microorganisms collected from acid mine drainage of different sites were mixed and then treated with mutagens NO2^- , diethyl sulfate （DES）, UV and their combinations, respectively. Five groups of mixed microorganisms with much stronger ore-leaching ability were obtained by screening on the leaching media. Among them, group E of mixed microorganisms （treated with 1% DES for 60 min） with the best perfonnance on chalcocite-leaching, increases the content of Cu^2＋ by 101.4% in 20 d of leaching compared with the control culture. In addition, group E is more tolerant to Cu^2＋ in media than the control without mutation treatment. Analysis for the diversity of microbial clones indicates that half of operational taxonomic units （OTUs） in group E are Acidithiobacillus ferrooxidans. These observations suggest that group E might have potentials for industrial application.
基金Project(2016RS2016)supported by the Hunan Provincial Science and Technology Leader(Innovation Team of Interface Chemistry of Efficient and Clean Utilization of Complex Mineral Resources),ChinaProject supported by the Co-Innovation Centre for Clean and Efficient Utilization of Strategic Metal Mineral Resources,ChinaProject(2015CX005)supported by the Innovation Driven Plan of Central South University,China
文摘Many researchers found that the Fe2+together with less amount of Cu2+can accelerate the leaching of chalcopyrite.In this work,the leaching of chalcopyrite with Cu2+was investigated.The leaching residuals were examined by Raman spectroscopy.Based on the leaching experiments,the chemical equilibrium in solution was calculated using Visual MINTEQ.The results showed that the Fe in chalcopyrite lattice was replaced by Cu2+;therefore,the chalcopyrite transformed into covellite.Furthermore,the formation of chalcocite occurred when Fe2+and Fe3+were added to the solution containing Cu2+.The copper extraction increased with a decrease of the initial redox potential(or the ratio of Fe3+/Fe2+).
