The bioleaching of two different types of low-grade copper tailings,acid-leaching tailings(ALT)and copper flotation tailings(CFT)by mixed moderate thermophiles,and the variation of mineralogical and microbiological ch...The bioleaching of two different types of low-grade copper tailings,acid-leaching tailings(ALT)and copper flotation tailings(CFT)by mixed moderate thermophiles,and the variation of mineralogical and microbiological characteristics during their dissolution processes were comparatively investigated.Results showed that bioleaching behaviors of the two types of tailings were significantly different.In ALT bioleaching,lower redox potential,higher[Fe3+]/[Fe2+]ratio and higher cell density in solution were obtained.These resulted in higher total copper,primary copper sulfide and secondary copper sulfide extractions,compared with CFT bioleaching.X-ray diffraction analysis suggested that gypsum and some metal organic complexes were detected in CFT bioleaching,which could cause the sluggish oxidation of sulphide minerals.The shifts of microbial community in the leachates and leaching residues varied greatly between ALT and CFT bioleaching.The percentage of iron-oxidizing bacteria in ALT bioleaching was higher than that of CFT,but the sulfur-oxidizing bacteria percentage was the opposite.The archaeon F.thermophilum L1 was detected in ALT but not in CFT.展开更多
The chemical,physical,thermal and texture properties of iron ores from different regions of Odisha and Chhattisgarh regions,India,have been investigated to understand the compositional variations of Fe,Al2O3,SiO2,S an...The chemical,physical,thermal and texture properties of iron ores from different regions of Odisha and Chhattisgarh regions,India,have been investigated to understand the compositional variations of Fe,Al2O3,SiO2,S and P.They were analyzed for its susceptibility to meet the industrial requirements,for various iron manufacture techniques.Chemical analysis indicated that the majority of the iron ores is rich in hematite(>90wt%),poor in gangue(<4.09wt%SiO2and<3.8wt%Al2O3)and deleterious elements(P<0.065wt%and S<0.016wt%)in all these iron ores found to be low.XRD peaks reviled that the gangue is in the form of kaolinite and quartz,and same was observed in Fourier transform infrared(FTIR)spectroscopy in the range of914to1034cm–1.The iron ores were found to have excellent physical properties exemplify with tumbler index(82wt%–91wt%),abrasion index(1.27wt%–4.87wt%)and shatter index(0.87wt%–1.64wt%).FTIR and thermal analysis were performed to assimilate the analysis interpolations.It was found that these iron ores exhibit three endothermic reactions,which are dehydration below447K with mass loss of0.13wt%to1.7wt%,dehydroxylation at525–609K with mass loss of1.09wt%–4.49wt%and decomposition of aluminosilicates at597–850K with mass loss of0.13wt%–1.15wt%.From this study,we can conclude that due to its excellent physico-chemical characteristics,these iron ores are suitable for BF and DRI operations.展开更多
基金Projects(31570113,41573072)supported by the National Natural Science Foundation of China
文摘The bioleaching of two different types of low-grade copper tailings,acid-leaching tailings(ALT)and copper flotation tailings(CFT)by mixed moderate thermophiles,and the variation of mineralogical and microbiological characteristics during their dissolution processes were comparatively investigated.Results showed that bioleaching behaviors of the two types of tailings were significantly different.In ALT bioleaching,lower redox potential,higher[Fe3+]/[Fe2+]ratio and higher cell density in solution were obtained.These resulted in higher total copper,primary copper sulfide and secondary copper sulfide extractions,compared with CFT bioleaching.X-ray diffraction analysis suggested that gypsum and some metal organic complexes were detected in CFT bioleaching,which could cause the sluggish oxidation of sulphide minerals.The shifts of microbial community in the leachates and leaching residues varied greatly between ALT and CFT bioleaching.The percentage of iron-oxidizing bacteria in ALT bioleaching was higher than that of CFT,but the sulfur-oxidizing bacteria percentage was the opposite.The archaeon F.thermophilum L1 was detected in ALT but not in CFT.
基金Project supported by the National Institute of Technology,Rourkela,India
文摘The chemical,physical,thermal and texture properties of iron ores from different regions of Odisha and Chhattisgarh regions,India,have been investigated to understand the compositional variations of Fe,Al2O3,SiO2,S and P.They were analyzed for its susceptibility to meet the industrial requirements,for various iron manufacture techniques.Chemical analysis indicated that the majority of the iron ores is rich in hematite(>90wt%),poor in gangue(<4.09wt%SiO2and<3.8wt%Al2O3)and deleterious elements(P<0.065wt%and S<0.016wt%)in all these iron ores found to be low.XRD peaks reviled that the gangue is in the form of kaolinite and quartz,and same was observed in Fourier transform infrared(FTIR)spectroscopy in the range of914to1034cm–1.The iron ores were found to have excellent physical properties exemplify with tumbler index(82wt%–91wt%),abrasion index(1.27wt%–4.87wt%)and shatter index(0.87wt%–1.64wt%).FTIR and thermal analysis were performed to assimilate the analysis interpolations.It was found that these iron ores exhibit three endothermic reactions,which are dehydration below447K with mass loss of0.13wt%to1.7wt%,dehydroxylation at525–609K with mass loss of1.09wt%–4.49wt%and decomposition of aluminosilicates at597–850K with mass loss of0.13wt%–1.15wt%.From this study,we can conclude that due to its excellent physico-chemical characteristics,these iron ores are suitable for BF and DRI operations.
