According to the analysis related to kinetic mechanism of vacuum denitrogenation and combining with the actual production of RH-MFB (a combination of Ruhstahl-Hausen vacuum degassing process with a multifunctional oxygen lance) at Liansteel, the limit step and model equation of vacuum denitrogenation are determined. Meanwhile, the influencing factors of nitrogen removal from liquid steel in vacuum of RH-MFB are analyzed. The results show that the limit step of vacuum denitrogenation in RH-MFB is the mass transfer of nitrogen in liquid boundary layer and the reaction follows first order kinetics. Keeping the necessary circulation time under the working pressure (67 Pa) is helpful to nitrogen removal from steel. The oxygen content in molten steel has little influence on the removal of nitrogen after deep deoxidation, while the sulphur content in liquid steel is always relatively low and has little effect on denitrogenation. The sharp decrease of carbon content in steel drives the process of denitrogenation reaction so as to exhibit a faster denitrogenation rate. The interfacial chemical reaction and argon blowing play a major role in the nitrogen removal when the carbon content in liquid steel is stable.
Abstract
According to the analysis related to kinetic mechanism of vacuum denitrogenation and combining with the actual production of RH-MFB (a combination of Ruhstahl-Hausen vacuum degassing process with a multifunctional oxygen lance) at Liansteel, the limit step and model equation of vacuum denitrogenation are determined. Meanwhile, the influencing factors of nitrogen removal from liquid steel in vacuum of RH-MFB are analyzed. The results show that the limit step of vacuum denitrogenation in RH-MFB is the mass transfer of nitrogen in liquid boundary layer and the reaction follows first order kinetics. Keeping the necessary circulation time under the working pressure (67 Pa) is helpful to nitrogen removal from steel. The oxygen content in molten steel has little influence on the removal of nitrogen after deep deoxidation, while the sulphur content in liquid steel is always relatively low and has little effect on denitrogenation. The sharp decrease of carbon content in steel drives the process of denitrogenation reaction so as to exhibit a faster denitrogenation rate. The interfacial chemical reaction and argon blowing play a major role in the nitrogen removal when the carbon content in liquid steel is stable.
关键词
RH /
denitrogenation /
kinetics /
influencing factors
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Key words
RH /
denitrogenation /
kinetics /
influencing factors
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参考文献
[1] FU Jie. Process Kinetics of the Metallurgy of Steel[M]. Beijing: the Publishing House of Metallurgical Industry, 2001.
[2] GUO Han-jie. Metallurgical Physical Chemistry[M]. Beijing: the Publishing House of Metallurgical Industry, 2004.
[3] ZHU Wan-jun. Investigation of Deep Denitrogenation Method During RH-KTB[D]. Wuhan: Wuhan University of Science and Technology, 2006.
[4] CHENG Guo-guang, ZHAO Pei, XU Xue-lu, et al. Process of Vacuum Denitrogenation of Steel[J]. Iron and Steel, 1999, 34(1): 16.
[5] FU Jie, CHANG He-ming, Di Lin, et al. Study on Kinetics of Nitrogen Removal From Liquid Steel Under Vacuum[J]. Iron and Steel, 2000, 35(10): 24.
[6] Shinme K, Matsuo T, Morishige M. Acceleration of Nitrogen Removal in Stainless Steel Under Reduced Pressure[J]. Trans ISIJ, 1988, 28(4): 297.
[7] Kitamura T, Miyamoto K, Tsujino R, et al. Mathematical Reaction Model for Nitrogen in Vacuum Degasser Desorption and Decarburization[J]. ISIJ Inter, 1996, 36(4): 395.
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