The effect of cooling rate on the crystallization of perovskite in high Ti-bearing blast furnace（BF） slag was studied using confocal scanning laser microscopy（CSLM）. Results showed that perovskite was the primary ...The effect of cooling rate on the crystallization of perovskite in high Ti-bearing blast furnace（BF） slag was studied using confocal scanning laser microscopy（CSLM）. Results showed that perovskite was the primary phase formed during the cooling of slag. On the slag surface, the growth of perovskite proceeded via the successive production of quasi-particles along straight lines, which further extended in certain directions. The morphology and structure of perovskite was found to vary as a function of cooling rate. At cooling rates of 10 and 30 K/min, the dendritic arms of perovskite crossed obliquely, while they were orthogonal at a cooling rate of 20 K/min and hexagonal at cooling rates of 40 and 50 K/min. These three crystal morphologies thus obtained at different cooling rates respectively corresponded to the orthorhombic, cubic and hexagonal crystal structures of perovskite. The observed change in the structure of perovskite could probably be attributed to the deficiency of O^2-, when Ti2O3 was involved in the formation of perovskite.展开更多
The velocity distribution of sinter and gas in vertical cooling furnace(VCF)has an important influence on gas-solid heat transfer.Based on the slot model of single hopper in the VCF of Meishan Iron and Steel Co.,Ltd.,...The velocity distribution of sinter and gas in vertical cooling furnace(VCF)has an important influence on gas-solid heat transfer.Based on the slot model of single hopper in the VCF of Meishan Iron and Steel Co.,Ltd.,the velocity and particle size distribution of sinter and the velocity and pressure distribution of gas were studied using a computational fluid dynamics-discrete element method model to obtain the gas-solid flow rule in the VCF.The results showed that the velocity of sinter near the wall and the edge of vent cowl was lower than that in the rest of the same plane.Therefore,the rectangular section of the vertical cooling furnace can be divided into a quasi-static zone,a plug flow zone and a convergent flow zone according to the flow velocity of the sinter.The average particle size and the void fraction of sinter bed were distributed in"W"and"V"shape along the width direction,respectively.The distribution of gas velocity in the furnace cavity was uneven,and the high-velocity area gradually changed from the center to the edge of the furnace cavity with the rise of gas.Reducing the ratio of edge to center gas flow from 2.7∶1 to 0.7∶1 could improve the gas velocity,but could not change the gas velocity distribution.The gas velocity distribution was more affected by the average particle size distribution of the sinter bed.It was suggested that measures need be taken to adjust it to improve the gas velocity distribution in the VCF.展开更多
基金financially supported by the National Natural Science Foundation of China(No.51090383)the Fundamental Research Funds for the Central Universities of China(No.CDJZR12130049)
文摘The effect of cooling rate on the crystallization of perovskite in high Ti-bearing blast furnace（BF） slag was studied using confocal scanning laser microscopy（CSLM）. Results showed that perovskite was the primary phase formed during the cooling of slag. On the slag surface, the growth of perovskite proceeded via the successive production of quasi-particles along straight lines, which further extended in certain directions. The morphology and structure of perovskite was found to vary as a function of cooling rate. At cooling rates of 10 and 30 K/min, the dendritic arms of perovskite crossed obliquely, while they were orthogonal at a cooling rate of 20 K/min and hexagonal at cooling rates of 40 and 50 K/min. These three crystal morphologies thus obtained at different cooling rates respectively corresponded to the orthorhombic, cubic and hexagonal crystal structures of perovskite. The observed change in the structure of perovskite could probably be attributed to the deficiency of O^2-, when Ti2O3 was involved in the formation of perovskite.
基金Financial support provided by the Fundamental Research Funds for the Central Universities of China(N2225022)is gratefully acknowledged.
文摘The velocity distribution of sinter and gas in vertical cooling furnace(VCF)has an important influence on gas-solid heat transfer.Based on the slot model of single hopper in the VCF of Meishan Iron and Steel Co.,Ltd.,the velocity and particle size distribution of sinter and the velocity and pressure distribution of gas were studied using a computational fluid dynamics-discrete element method model to obtain the gas-solid flow rule in the VCF.The results showed that the velocity of sinter near the wall and the edge of vent cowl was lower than that in the rest of the same plane.Therefore,the rectangular section of the vertical cooling furnace can be divided into a quasi-static zone,a plug flow zone and a convergent flow zone according to the flow velocity of the sinter.The average particle size and the void fraction of sinter bed were distributed in"W"and"V"shape along the width direction,respectively.The distribution of gas velocity in the furnace cavity was uneven,and the high-velocity area gradually changed from the center to the edge of the furnace cavity with the rise of gas.Reducing the ratio of edge to center gas flow from 2.7∶1 to 0.7∶1 could improve the gas velocity,but could not change the gas velocity distribution.The gas velocity distribution was more affected by the average particle size distribution of the sinter bed.It was suggested that measures need be taken to adjust it to improve the gas velocity distribution in the VCF.
