粉末压片法制样,选用标准样品,以经验α系数和散射线内标法校正元素谱线重叠干扰和基体效应,使用ZSX Primus X射线荧光光谱仪对多金属矿样品中、低含量的铜、铅、锌、钼、钨和硫等元素同时进行快速测定,方法的测试范围为:Cu:0.0030%—5....粉末压片法制样,选用标准样品,以经验α系数和散射线内标法校正元素谱线重叠干扰和基体效应,使用ZSX Primus X射线荧光光谱仪对多金属矿样品中、低含量的铜、铅、锌、钼、钨和硫等元素同时进行快速测定,方法的测试范围为:Cu:0.0030%—5.00%;Pb:0.0050%—5.00%;Zn:0.010%—5.00%;Mo:0.0030%—1.50%;W:0.005%—2.00%;S:0.010%—10.00%。方法测定值与标准值、ICP-OES/MS、比色分析、红外碳硫分析数据基本吻合,可满足实验室对多种多金属矿石批量检测的要求。展开更多
The reduction-degree of the sample increases and the utilization ratio of gas decreases when the reaction lasts longer time,which indicates that the reaction is faster at the beginning of reduction,while it becomes sl...The reduction-degree of the sample increases and the utilization ratio of gas decreases when the reaction lasts longer time,which indicates that the reaction is faster at the beginning of reduction,while it becomes slower in subsequent process.The higher the reaction temperature,the higher the utilization ratio of gas and the reduction-degree are,but the difference of utilization ratio among the different temperatures becomes smaller with time.The utilization ratio of gas can reach about 8% and the reduction-degree is 80% for 20 min reduction at 850 ℃,indicating that the reduction reaction by CO is very fast at high temperature.The higher the reaction temperature,the higher the apparent reaction rate constant is,but the difference of apparent reaction rate constant among the different temperatures becomes bigger.The apparent activation energy is about 59.11 kJ/mol in the fluidized bed experiment.The increase of reduction-degree with gas velocity shows quite good linearity,indicating that at high temperature even higher velocity of reducing gas can be used to improve the productivity of reactor when CO is used as reducing gas.With the increase of charge height,the metallization ratio and the reduction-degree decrease,but the utilization ratio of gas increases.展开更多
Due to the instability of FeO at temperatures below 843 K,the fuidization reduction pathway of iron ore powder changes with the reduction temperature.Thus,the effect of temperature and reaction pathway interaction on ...Due to the instability of FeO at temperatures below 843 K,the fuidization reduction pathway of iron ore powder changes with the reduction temperature.Thus,the effect of temperature and reaction pathway interaction on the kinetics of fuidization reduction of iron ore powder under low-temperature conditions ranging from 783 to 903 K was investigated to describe the fluidization reduction rate of iron ore powder from three aspects:microstructure change,reaction limiting link,and apparent activation energy of the reaction,exploring their internal correlation.The experimental results revealed that in a temperature range of 783-813 K,the formation of a dense iron layer hindered the internal diffusion of reducing gas,resulting in relatively high gas diffusion resistance.In addition,due to the differences in limiting links and reaction pathways in the intermediate stage of reduction,the apparent activation energy of the reaction varied.The apparent activation energy of the reaction ranged from 23.36 to 89.13 kJ/mol at temperature ranging from 783 to 813 K,while it ranged from 14.30 to 68.34 kJ/mol at temperature ranging from 873 to 903 K.展开更多
Mauritanian iron ore powder(OM)has advantages of high iron grade,low aluminum content,and low loss on ignition,which can be used as a new mineral to replace low alumina limonite that has been exhausted in Australia.Ho...Mauritanian iron ore powder(OM)has advantages of high iron grade,low aluminum content,and low loss on ignition,which can be used as a new mineral to replace low alumina limonite that has been exhausted in Australia.However,it will have a certain negative impact on sintering because of its high SiO_(2) content.The mechanism of SiO_(2) content affecting the sintering behavior was first studied through FactSage 7.2.Then,the liquid fluidity,penetration,and high-temperature performance of different iron ore powders were compared.Finally,the optimization of ore blending structure was studied by the micro-sintering method and the sinter pot test.The results show that the increase in SiO_(2) content can reduce the assimilation temperature.The low penetration of OM can lead to an increase in the amount of liquid,and the high SiO_(2) content of OM increases the viscosity of the liquid phase.What is more,the increase in SiO_(2) also increases the formation of silicate and fayalite phase and inhibits the formation of silico-ferrite of calcium and aluminum(SFCA).To optimize ore blending structure,OM and the low SiO_(2) powder OD from Australia were used together,which improves the content of SFCA by 2.04%and decreases the contents of calcium silicate and fayalite by 0.63%and 4.99%,respectively.The results of the sinter pot test indicated that the properties of sinter have been improved.展开更多
The reduction of 1-3 mm fine powder of iron ore by H2 was conducted in a lab-fabricated kg class high temperature fluidized bed. The results show that the differential pressure in the fluidized bed, which has small fl...The reduction of 1-3 mm fine powder of iron ore by H2 was conducted in a lab-fabricated kg class high temperature fluidized bed. The results show that the differential pressure in the fluidized bed, which has small fluctuation with time, increases with the increase of gas flowing velocity. The utilization ratio of gas decreases when the reaction lasts longer time indicating that the reaction is faster at the beginning of reduction and becomes slower in the latter process. The higher the reaction temperature is, the higher the utilization ratio of gas is, but the difference of utilization ratio among the different temperatures becomes smaller with time. The utilization ratio of gas and the metallization ratio can reach 9% and 84% respectively at 750℃ for 20 min, which shows the reduction reaction by H2 is very fast. The increase of metallization ratio with gas velocity performs quite good linearity, which shows that a higher velocity of reducing gas can be used to improve the productivity of the reactor when H2 is used as reducing gas. With the increase of charge height, the metallization ratio decreases, but the utilization ratio of gas increases. The reaction temperature can be reduced to 700-750℃ from 800-850℃ when H2 is used as reducing gas.展开更多
文摘粉末压片法制样,选用标准样品,以经验α系数和散射线内标法校正元素谱线重叠干扰和基体效应,使用ZSX Primus X射线荧光光谱仪对多金属矿样品中、低含量的铜、铅、锌、钼、钨和硫等元素同时进行快速测定,方法的测试范围为:Cu:0.0030%—5.00%;Pb:0.0050%—5.00%;Zn:0.010%—5.00%;Mo:0.0030%—1.50%;W:0.005%—2.00%;S:0.010%—10.00%。方法测定值与标准值、ICP-OES/MS、比色分析、红外碳硫分析数据基本吻合,可满足实验室对多种多金属矿石批量检测的要求。
基金Item Sponsored by National Natural Science Foundation of China(50474006)National Key Technology Research and Development Programin 11th Five-Year Plan of China(2006BAE03A12,2006BAE03A05)
文摘The reduction-degree of the sample increases and the utilization ratio of gas decreases when the reaction lasts longer time,which indicates that the reaction is faster at the beginning of reduction,while it becomes slower in subsequent process.The higher the reaction temperature,the higher the utilization ratio of gas and the reduction-degree are,but the difference of utilization ratio among the different temperatures becomes smaller with time.The utilization ratio of gas can reach about 8% and the reduction-degree is 80% for 20 min reduction at 850 ℃,indicating that the reduction reaction by CO is very fast at high temperature.The higher the reaction temperature,the higher the apparent reaction rate constant is,but the difference of apparent reaction rate constant among the different temperatures becomes bigger.The apparent activation energy is about 59.11 kJ/mol in the fluidized bed experiment.The increase of reduction-degree with gas velocity shows quite good linearity,indicating that at high temperature even higher velocity of reducing gas can be used to improve the productivity of reactor when CO is used as reducing gas.With the increase of charge height,the metallization ratio and the reduction-degree decrease,but the utilization ratio of gas increases.
基金The authors gratefully acknowledge financial support by the National Natural Science Foundation of China-Xinjiang Joint Fund(U2003124)the National Natural Science Foundation of China(No.51974001)the University Outstanding Young Talents Funding Program(No.gxyq2019016).
文摘Due to the instability of FeO at temperatures below 843 K,the fuidization reduction pathway of iron ore powder changes with the reduction temperature.Thus,the effect of temperature and reaction pathway interaction on the kinetics of fuidization reduction of iron ore powder under low-temperature conditions ranging from 783 to 903 K was investigated to describe the fluidization reduction rate of iron ore powder from three aspects:microstructure change,reaction limiting link,and apparent activation energy of the reaction,exploring their internal correlation.The experimental results revealed that in a temperature range of 783-813 K,the formation of a dense iron layer hindered the internal diffusion of reducing gas,resulting in relatively high gas diffusion resistance.In addition,due to the differences in limiting links and reaction pathways in the intermediate stage of reduction,the apparent activation energy of the reaction varied.The apparent activation energy of the reaction ranged from 23.36 to 89.13 kJ/mol at temperature ranging from 783 to 813 K,while it ranged from 14.30 to 68.34 kJ/mol at temperature ranging from 873 to 903 K.
基金The authors would like to thank the the National Key Research and Development Program of China(Grant Nos.2021YFC2902400 and 2021YFC2902404)the National Natural Science Foundation of China(Grant Nos.51904023 and 51804027).
文摘Mauritanian iron ore powder(OM)has advantages of high iron grade,low aluminum content,and low loss on ignition,which can be used as a new mineral to replace low alumina limonite that has been exhausted in Australia.However,it will have a certain negative impact on sintering because of its high SiO_(2) content.The mechanism of SiO_(2) content affecting the sintering behavior was first studied through FactSage 7.2.Then,the liquid fluidity,penetration,and high-temperature performance of different iron ore powders were compared.Finally,the optimization of ore blending structure was studied by the micro-sintering method and the sinter pot test.The results show that the increase in SiO_(2) content can reduce the assimilation temperature.The low penetration of OM can lead to an increase in the amount of liquid,and the high SiO_(2) content of OM increases the viscosity of the liquid phase.What is more,the increase in SiO_(2) also increases the formation of silicate and fayalite phase and inhibits the formation of silico-ferrite of calcium and aluminum(SFCA).To optimize ore blending structure,OM and the low SiO_(2) powder OD from Australia were used together,which improves the content of SFCA by 2.04%and decreases the contents of calcium silicate and fayalite by 0.63%and 4.99%,respectively.The results of the sinter pot test indicated that the properties of sinter have been improved.
基金supported by the National Nature Science Foundation of China(No.50474006)the National Science and Technology Support Program for the 11th Five-Year Plan of China(No.2006BAE03A12 and No.2006BAE03A05)
文摘The reduction of 1-3 mm fine powder of iron ore by H2 was conducted in a lab-fabricated kg class high temperature fluidized bed. The results show that the differential pressure in the fluidized bed, which has small fluctuation with time, increases with the increase of gas flowing velocity. The utilization ratio of gas decreases when the reaction lasts longer time indicating that the reaction is faster at the beginning of reduction and becomes slower in the latter process. The higher the reaction temperature is, the higher the utilization ratio of gas is, but the difference of utilization ratio among the different temperatures becomes smaller with time. The utilization ratio of gas and the metallization ratio can reach 9% and 84% respectively at 750℃ for 20 min, which shows the reduction reaction by H2 is very fast. The increase of metallization ratio with gas velocity performs quite good linearity, which shows that a higher velocity of reducing gas can be used to improve the productivity of the reactor when H2 is used as reducing gas. With the increase of charge height, the metallization ratio decreases, but the utilization ratio of gas increases. The reaction temperature can be reduced to 700-750℃ from 800-850℃ when H2 is used as reducing gas.
