The images of granular ore media were captured by X-ray CT scanner. Combined with digital image processing and finite element techniques, the three-dimensional geometrical model, which represents the realistic pore st...The images of granular ore media were captured by X-ray CT scanner. Combined with digital image processing and finite element techniques, the three-dimensional geometrical model, which represents the realistic pore structure of the media, was constructed. With this model, three dimensional pore scale fluid flow among particles was simulated. Then the distributions of fluid flow velocity and pressure were analyzed and the hydraulic conductivity was calculated. The simulation results indicate the fluid flow behaviors are mainly dominated by the volume and topological structure of pore space. There exist obvious preferential flow and leaching blind zones simultaneously in the medium. The highest velocities generally occur in those narrow pores with high pressure drops. The hydraulic conductivity obtained by simulation is the same order of magnitude as the laboratory test result, which denotes the validity of the model. The pore-scale and macro-scale are combined and the established geometrical model can be used for the simulations of other phenomena during heap leaching process.展开更多
Reducing NO_(x) emission of iron ore sintering process in a cost effective manner is a challenge for the iron and steel industry at present.Effects of the proportion of mill scale and coke breeze on the NO_(x) emissio...Reducing NO_(x) emission of iron ore sintering process in a cost effective manner is a challenge for the iron and steel industry at present.Effects of the proportion of mill scale and coke breeze on the NO_(x) emission,strength of sinter,and sinter indexes were studied by com-bustion and sinter pot tests.Results showed that the peak value of NO concentration,total of NO emission,and fuel-N conversion rate gradu-ally decreased as the proportions of the mill scale increased because NO was reduced to N_(2) by Fe_(3)O_(4),FeO,and Fe in the mill scale.The strength of sinter reached the highest value at 8.0wt%mill scale due to the formation of minerals with low melting point.The fuel-N conver-sion rate slightly fluctuated and total NO_(x) emission significantly decreased with the decreased proportions of coke breeze because CO forma-tion and content of N element in the sintered mixture decreased.However,the sinter strength also decreased due to the decrease in the amount of the melting minerals.Furthermore,results of the sinter pot tests indicated that NO_(x) emission decreased.The sinter indexes performed well when the proportions of mill scale and coke breeze were 8.0wt%and 3.70wt%respectively in the sintered mixture.展开更多
基金Projects (50934002, 51074013, 51104100) supported by the National Natural Science Foundation of China
文摘The images of granular ore media were captured by X-ray CT scanner. Combined with digital image processing and finite element techniques, the three-dimensional geometrical model, which represents the realistic pore structure of the media, was constructed. With this model, three dimensional pore scale fluid flow among particles was simulated. Then the distributions of fluid flow velocity and pressure were analyzed and the hydraulic conductivity was calculated. The simulation results indicate the fluid flow behaviors are mainly dominated by the volume and topological structure of pore space. There exist obvious preferential flow and leaching blind zones simultaneously in the medium. The highest velocities generally occur in those narrow pores with high pressure drops. The hydraulic conductivity obtained by simulation is the same order of magnitude as the laboratory test result, which denotes the validity of the model. The pore-scale and macro-scale are combined and the established geometrical model can be used for the simulations of other phenomena during heap leaching process.
基金This work was financially supported by the National Natural Science Foundation of China(No.51904127)the Natural Science Foundation of Jiangxi Province,China(No.20192BAB216018)+1 种基金the research and development Project(No.2018-YYB-05)collaborative innovation Project(No.2018-XTPH1-05)of Jiangxi Academy of Sciences,China.
文摘Reducing NO_(x) emission of iron ore sintering process in a cost effective manner is a challenge for the iron and steel industry at present.Effects of the proportion of mill scale and coke breeze on the NO_(x) emission,strength of sinter,and sinter indexes were studied by com-bustion and sinter pot tests.Results showed that the peak value of NO concentration,total of NO emission,and fuel-N conversion rate gradu-ally decreased as the proportions of the mill scale increased because NO was reduced to N_(2) by Fe_(3)O_(4),FeO,and Fe in the mill scale.The strength of sinter reached the highest value at 8.0wt%mill scale due to the formation of minerals with low melting point.The fuel-N conver-sion rate slightly fluctuated and total NO_(x) emission significantly decreased with the decreased proportions of coke breeze because CO forma-tion and content of N element in the sintered mixture decreased.However,the sinter strength also decreased due to the decrease in the amount of the melting minerals.Furthermore,results of the sinter pot tests indicated that NO_(x) emission decreased.The sinter indexes performed well when the proportions of mill scale and coke breeze were 8.0wt%and 3.70wt%respectively in the sintered mixture.
