K₂CO₃ catalysis on the reactivity of top charged coke and stamp charged coke

Abstract

The catalysis of K₂CO₃ on the reactivity of top charged coke and stamp charged coke from Pansteel in China was studied. The coke reaction index of the stamp charged coke was 1%–2% higher than that of the top charged coke. Under the catalysis of K₂CO₃, the coke reaction index of both cokes approximately increased by 4%, 6%, 10% and 6% at 900, 1000, 1100 and 1200°C, respectively. The reactivity of the K-enriched stamp charged coke was 1%–2% higher than that of the K-enriched top charged coke below 1100°C. However, only negligible differences were found in the temperature zone between 1100 and 1200°C. Scanning electron microscopy images illustrated that pores in the top charged coke were smaller and equally distributed, while relatively more big pores exist non-homogenously in stamp charged coke. Due to the different processes in production, the stamp charged coke was more porous and most of the pores tended to be applanate. Cracks were observed in the microstructure of the stamp charged coke during the carbon solution reaction, implying the inferior quality of the stamp charged coke to the top charged coke at high temperature. Diffusion of K during the carbon solution reaction was studied by the energy dispersive spectrometry. It is found that K gradually spreads into the center of lumpy coke with the rising of temperature and is equally distributed on the edges of pores at 1200°C. Besides, oxidation reactions of functional groups become faster with the catalysis of K.content

Keywords

blast furnaces / coke / alkali metals / catalysis / reactivity

References

[1] Naito M., Nomura S., Kato K. Development of production and utilization technology of coke with high strength and high reactivity. Tetsu-To-Hagane, 2010, 96(5): 201.

[2] Nomura S., Callcott T.G. Maximum rates of pulverized coal injection in ironmaking blast furnaces. ISIJ Int., 2011, 51(7): 1033.

[3] H.M. Wang, C.L. Wang, X.H. Zhou, and Y. Wang, The relation between metallurgical properties of coke and regular B.F. performance, Laigang Sci. Technol., 2009, No. 1, p. 64.

[4] Pusz S., Krzesińska M., Smędowski Majewska J., Pilawaa B., Kwiecińska B. Changes in a coke structure due to reaction with carbon dioxide. Int. J. Coal Geol., 2010, 81(4): 287.

[5] Grigore M., Sakurovs R., French D., Sahajwalla V. Coke gasification: the influence and behavior of inherent catalytic mineral matter. Energy Fuels, 2009, 23(4): 2075.

[6] J.J. Xu, G. Liu, H.Y. Wei, and Y.L. Xu, The production practice that use stamping coke to smelt at No. 4 BF in Hangang, Ironmaking Technol. Commun., 2009, No. 1, p. 3.

[7] Krishnan S.H., Dash R.S., Guha M., Kumar D., Deshpande D.P. Application of binder in stamp charge coke making. ISIJ Int., 2004, 44(7): 1150.

[8] Dash P.S., Krishnan S.H., Sharma R., Banerjee P.K., Haldar S.K. Laboratory scale investigation to improve the productivity of stamp charge coke oven through optimisation of bulk density of coal cake. ISIJ Int., 2005, 45(11): 1577.

[9] X.S. Gao and A.M. Zhang, BF smelting with completely stamping coke, [in] Academic Annual Conference of Small and Middle Sized Blast Furnace, 2008, p. 473.

[10] Banerjee P.K., Krishnan S.H., Baijal A.D. Stamp charged coke making technology. Trans. Indian Inst. Met., 2006, 59(5): 535.

[11] Cao J.L. The production practice that use stamping coke to smelt at No. 2 BF in Pangang. Sichuan Metall., 2010, 32(6): 35.

[12] Wang G., Liu Y. The production practice that use stamping coke to smelt at Pansteel BF. Sichuan Metall., 2010, 32(3): 28.

[13] Fu Y.N. Blast Furnace Coke, 1995, Beijing, Metallurgical Industry Press, 84.

[14] Hilding T., Gupta S., Sahajwalla V., Björkman B., Wikström J. Degradation behaviour of a high CSR coke in an experimental blast furnace: effect of carbon structure and alkali reactions. ISIJ Int., 2005, 45(7): 1041.

[15] Nomura S., Naito M., Yamaguchi K. Post-reaction strength of catalyst-added highly reactive coke. ISIJ Int., 2007, 47(6): 831.