1 School of Metallurgical Engineering, Xi’an University of Architecture and Technology, Xi’an 710055, Shaanxi, China 2 China International Engineering Consulting Corporation, Beijing 100048, China 3 School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083, China
Reduction behavior of iron ore powder by high-volatile coal in thermogravimetric–gas chromatographic and kinetic analysis
1 School of Metallurgical Engineering, Xi’an University of Architecture and Technology, Xi’an 710055, Shaanxi, China 2 China International Engineering Consulting Corporation, Beijing 100048, China 3 School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083, China
摘要 The reduction behavior of iron ore powder by high-volatile coal was investigated, and its kinetic mechanism was clarified. The effect of volatiles in coal on the reduction reaction of iron ore was compared by utilizing a Xinjiang lignite with a high volatile content and its pyrolysis carbon produced by high-temperature pyrolysis to remove volatiles, serving as a reductant. The mass loss and gas composition of the samples during the reduction process were detected using thermogravimetric analysis and gas chromatography, and the morphological changes of iron ore powder were observed through scanning electron microscopy. The kinetic parameters of the iron oxide reduction reaction were calculated by the Flynn–Ozawa–Wall method, and the kinetic mechanism of volatile participation in the iron oxide reduction reaction was determined through the Coats–Redfern method. The results indicate that the coupling effect between the high-volatile coal pyrolysis and reduction reactions occurs during the second stage of the entire coupling process, which corresponds to the late stage of coal pyrolysis with a substantial release of H2 and CO. The volatiles in coal actively participated in the reduction reaction, reducing the initiation temperature of the reaction by around 200 °C. The reduction of iron oxides by high-volatile coal was jointly promoted by the ‘‘hydrogen cycle’’ and ‘‘carbon cycle’’, resulting in a higher reduction extent and metallization rate at the end of the reaction. When high-volatile coal was used as the reductant, the average activation energy for the entire process was 76.5 kJ/mol, a significant decrease compared to the employment of pyrolysis carbon without volatiles as the reductant (1167 kJ/mol).
Abstract：The reduction behavior of iron ore powder by high-volatile coal was investigated, and its kinetic mechanism was clarified. The effect of volatiles in coal on the reduction reaction of iron ore was compared by utilizing a Xinjiang lignite with a high volatile content and its pyrolysis carbon produced by high-temperature pyrolysis to remove volatiles, serving as a reductant. The mass loss and gas composition of the samples during the reduction process were detected using thermogravimetric analysis and gas chromatography, and the morphological changes of iron ore powder were observed through scanning electron microscopy. The kinetic parameters of the iron oxide reduction reaction were calculated by the Flynn–Ozawa–Wall method, and the kinetic mechanism of volatile participation in the iron oxide reduction reaction was determined through the Coats–Redfern method. The results indicate that the coupling effect between the high-volatile coal pyrolysis and reduction reactions occurs during the second stage of the entire coupling process, which corresponds to the late stage of coal pyrolysis with a substantial release of H2 and CO. The volatiles in coal actively participated in the reduction reaction, reducing the initiation temperature of the reaction by around 200 °C. The reduction of iron oxides by high-volatile coal was jointly promoted by the ‘‘hydrogen cycle’’ and ‘‘carbon cycle’’, resulting in a higher reduction extent and metallization rate at the end of the reaction. When high-volatile coal was used as the reductant, the average activation energy for the entire process was 76.5 kJ/mol, a significant decrease compared to the employment of pyrolysis carbon without volatiles as the reductant (1167 kJ/mol).
Rui-meng Shi,Qi-yuan Mi,Bin Li, et al. Reduction behavior of iron ore powder by high-volatile coal in thermogravimetric–gas chromatographic and kinetic analysis[J]. Journal of Iron and Steel Research International, 2024, 31(1): 92-107.
2024, Vol. 31 
