The chemical compositions,mineralogical characteristics,as well as dissemination of iron-and phosphorus-based minerals were studied for the E’xi oolitic hematite from western Hubei Province in China by using chemical...The chemical compositions,mineralogical characteristics,as well as dissemination of iron-and phosphorus-based minerals were studied for the E’xi oolitic hematite from western Hubei Province in China by using chemical analysis,optical microscope,electron probe micro-analyzer(EPMA)and energy dispersive spectroscopy(EDS).It is found that this kind of oolitic hematite ore contains 47.71%TFe,10.96%SiO_2,as well as 0.874%P,with hematite as the dominant Fe-bearing minerals,and quartz,chamosite,illite and cellophane as main gangue minerals.The microscope examination showed that the ore has an oolitic structure,with some ooids principally formed by a series of concentric layers of hematite collophanite around nucleus that is hematite in the association with collophanite.Based on the EPMA and EDS analysis,it can be known that some ooids are primarily composed of hematite and collophanite.The separation can be achieved through fine grinding for those collophanite laminae with a higher P content.However,the dissemination of two minerals at the interface will result in the difficulty in effective separation.Besides,some ooids are made of chamosite with some nucleus formed of quartz,which is principally finely disseminated with hematite.In view of the close association and dissemination of iron-and phosphorus-based minerals in the ooids,it is found that the process of stage-grindings and stage-separations can be adopted to effectively increase the iron recovery and decrease the P content in the concentrate to some extent.展开更多
A 3D model applying temperature-and carbon concentration-dependent material properties was developed to describe the scrap melting behavior and carbon diffusion under natural convection.Simulated results agreed reason...A 3D model applying temperature-and carbon concentration-dependent material properties was developed to describe the scrap melting behavior and carbon diffusion under natural convection.Simulated results agreed reasonably well with experimental ones.Scrap melting was subdivided into four stages:formation of a solidified layer,rapid melting of the solidified layer,carburization,and carburization+normal melting.The carburization stage could not be ignored at low temperature because the carburization time for the sample investigated was 214 s at 1573 K compared to 12 s at 1723 K.The thickness of the boundary layer with significant concentration difference at 1573 K increased from 130μm at 5 s to 140μm at 60 s.The maximum velocity caused by natural convection decreased from 0.029 m·s^(−1)at 5 s to 0.009 m·s^(−1)at 634 s because the differences in temperature and density between the molten metal and scrap decreased with time.展开更多
Background Restocking by introducing hatchery-reared fish into wild habitats aids in the restoration of fishery aquatic ecosystems and reefs to increase the abundance of fish resources,restore the ecological balance o...Background Restocking by introducing hatchery-reared fish into wild habitats aids in the restoration of fishery aquatic ecosystems and reefs to increase the abundance of fish resources,restore the ecological balance of water bodies,and enhance ecosystem functioning.Accurately,rapidly,and effectively evaluating the success of restocking using chemical markers(e.g.,strontium[Sr])remains challenging for fisheries management.Consequently,for nonlethal fish sampling,hard tissues,such as fin rays,have received increasing attention as a target for marking method.However,data on the differences in marking different types of fin rays remain limited.Therefore,we exposed juvenile blunt snout bream individuals(Megalobrama amblycephala)to 0(control group)or 800 mg/L of SrCl_(2)·6H_(2)O(marked group)for 5 days and transferred them into normal aerated water for post-immersion culture.We sampled their pectoral,dorsal,ventral,anal,and caudal fin rays.The Sr marks among the fin types were sampled at 0 and 20 days post-immersion and evaluated using an electron probe micro-analyzer(EPMA)for the five-day Sr/Ca ratios,along with line transect and Sr mapping analyses.Results Sr marking signatures were observed in all fin types in the marked group,with a success rate of up to 100%.Although marking efficiency varied among the different fin ray types,the highest Sr/Ca ratios were most often detected in the dorsal fin.Cross-sectional Sr concentration maps of all fin rays sampled showed high-Sr domains in the marked group;in contrast,the entire cross-sections of the control group displayed low Sr contents,indicating successful marking efficiency.Conclusions Fin ray Sr marking is a successful method for juvenile M.amblycephala,with the advantages of nonlethality and negligible sampling injuries,facilitating the rapid and effective evaluation of Sr marking in restocking M.amblycephala.展开更多
基金Project(51474161)supported by the National Natural Science Foundation of China
文摘The chemical compositions,mineralogical characteristics,as well as dissemination of iron-and phosphorus-based minerals were studied for the E’xi oolitic hematite from western Hubei Province in China by using chemical analysis,optical microscope,electron probe micro-analyzer(EPMA)and energy dispersive spectroscopy(EDS).It is found that this kind of oolitic hematite ore contains 47.71%TFe,10.96%SiO_2,as well as 0.874%P,with hematite as the dominant Fe-bearing minerals,and quartz,chamosite,illite and cellophane as main gangue minerals.The microscope examination showed that the ore has an oolitic structure,with some ooids principally formed by a series of concentric layers of hematite collophanite around nucleus that is hematite in the association with collophanite.Based on the EPMA and EDS analysis,it can be known that some ooids are primarily composed of hematite and collophanite.The separation can be achieved through fine grinding for those collophanite laminae with a higher P content.However,the dissemination of two minerals at the interface will result in the difficulty in effective separation.Besides,some ooids are made of chamosite with some nucleus formed of quartz,which is principally finely disseminated with hematite.In view of the close association and dissemination of iron-and phosphorus-based minerals in the ooids,it is found that the process of stage-grindings and stage-separations can be adopted to effectively increase the iron recovery and decrease the P content in the concentrate to some extent.
基金the National Key R&D Program of China(No.2019YFC1905701)the National Natural Science Foundation of China(Nos.51674022,51734003)the Key projects of NSFC(No.U1960201).
文摘A 3D model applying temperature-and carbon concentration-dependent material properties was developed to describe the scrap melting behavior and carbon diffusion under natural convection.Simulated results agreed reasonably well with experimental ones.Scrap melting was subdivided into four stages:formation of a solidified layer,rapid melting of the solidified layer,carburization,and carburization+normal melting.The carburization stage could not be ignored at low temperature because the carburization time for the sample investigated was 214 s at 1573 K compared to 12 s at 1723 K.The thickness of the boundary layer with significant concentration difference at 1573 K increased from 130μm at 5 s to 140μm at 60 s.The maximum velocity caused by natural convection decreased from 0.029 m·s^(−1)at 5 s to 0.009 m·s^(−1)at 634 s because the differences in temperature and density between the molten metal and scrap decreased with time.
基金financed by project grant 2022YFF0608203 of the National Key Research and Development Programproject grant KYCX22_0706 of the Postgraduate Research&Practice Innovation Program of Jiangsu Province
文摘Background Restocking by introducing hatchery-reared fish into wild habitats aids in the restoration of fishery aquatic ecosystems and reefs to increase the abundance of fish resources,restore the ecological balance of water bodies,and enhance ecosystem functioning.Accurately,rapidly,and effectively evaluating the success of restocking using chemical markers(e.g.,strontium[Sr])remains challenging for fisheries management.Consequently,for nonlethal fish sampling,hard tissues,such as fin rays,have received increasing attention as a target for marking method.However,data on the differences in marking different types of fin rays remain limited.Therefore,we exposed juvenile blunt snout bream individuals(Megalobrama amblycephala)to 0(control group)or 800 mg/L of SrCl_(2)·6H_(2)O(marked group)for 5 days and transferred them into normal aerated water for post-immersion culture.We sampled their pectoral,dorsal,ventral,anal,and caudal fin rays.The Sr marks among the fin types were sampled at 0 and 20 days post-immersion and evaluated using an electron probe micro-analyzer(EPMA)for the five-day Sr/Ca ratios,along with line transect and Sr mapping analyses.Results Sr marking signatures were observed in all fin types in the marked group,with a success rate of up to 100%.Although marking efficiency varied among the different fin ray types,the highest Sr/Ca ratios were most often detected in the dorsal fin.Cross-sectional Sr concentration maps of all fin rays sampled showed high-Sr domains in the marked group;in contrast,the entire cross-sections of the control group displayed low Sr contents,indicating successful marking efficiency.Conclusions Fin ray Sr marking is a successful method for juvenile M.amblycephala,with the advantages of nonlethality and negligible sampling injuries,facilitating the rapid and effective evaluation of Sr marking in restocking M.amblycephala.
