Abstract
The reduction kinetics and mechanisms of hematite ore with various particle sizes with hydrogen at low temperature were studied using the thermogravimetric analysis. At the same temperature, after the particle size of powder decreases from 107.5 μm to 2.0 μm, the surface area of the powder and the contact area between the powder and gas increase, which makes the reduction process of hematite accelerate by about 8 times, and the apparent activation energy of the reduction reaction drops to 36.9 kJ/mol from 78.3 kJ/mol because the activity of ore powder is improved by refining gradually. With the same reaction rate, the reaction temperature of 6.5 μm powder decreases by about 80 °C compared with that of 107.5 μm powder. Thinner diffusion layer can also accelerate the reaction owing to powder refining. The higher the temperature, the greater is the peak of the reduction rate; at the same temperature, the greater the particle size, the smaller is the peak value of the reduction rate; both inner diffusion and interface chemical reaction play an important role in the whole reaction process.
Similar content being viewed by others
References
Sujoy K Dutta, Ahindra Ghosh. Kinetics of Gaseous Reduction of Iron Ore Fines [J]. ISIJ International, 1993, 33(11): 1168.
Pineau A, Kanari N, Gaballah I. Kinetics of Reduction of Iron Oxides by H2 Part I: Low Temperature Reduction of Hematite [J]. Thermochimica Acta, 2006, 447(1): 89.
Rodriguez R A D, Coneio A N, Bedolla E B. Kinetics of Reduction of Fe2O3 Particles With H2-CO Mixtures at Low Temperatures [J]. Iron and Steelmaker, 2003, 30(1): 25.
ZHAO Pei, GUO Pei-min, ZHANG Dian-wei. Study on Reduction Sequence of Hematite at Low-Temperature Non-Equilibrium State [J]. Iron and Steel, 2006, 41(8): 12 (in Chinese).
ZHAO Pei, GUO Pei-min. Study on Promotion of Metallurgical Reactions by Nanocrystallization of Reactants [J]. Iron and Steel, 2005, 40(6): 6 (in Chinese).
Edstrom J O. The Mechanism of Reduction of Iron Oxides [J]. Journal of the Iron and Steel Institute, 1953, 175(11): 289.
Unal A, Bradshaw A V. Rate Processes and Structural Changes in Gaseous Reduction of Hematite Particles to Magnetite [J]. Metallurgical and Materials Transactions, 1983, 14B(4): 743.
Mckewan W M. Kinetics of Iron Oxide Reduction [J]. Trans Met Soc AIME, 1960, 218(2): 2.
Spitzer R H, Manning F S, Philbrook W O. Mixed-Control Reaction Kinetics in the Gaseous Reduction of Hematite [J]. Trans Met Soc AIME, 1966, 236(5): 726.
Spitzer R H, Manning F S, Philbrook W O. Generalized Model for the Gaseous, Topochemical Reduction of Porous Hematite Spheres [J]. Trans Met Soc AIME, 1966, 236(12): 1715.
Turkdogan E T, Vinters J V. Gaseous Reduction of Iron Oxides: Part I. Reduction of Hematite in Hydrogen [J]. Metallurgical and Materials Transactions, 1971, 2B(11): 3175.
HUA Yi-xin. Metallurgical Process Dynamics Introduction [M]. Beijing: Metallurgical Industry Press, 2004 (in Chinese).
ZHANG Dian-wei. Fundamental Research of a New Process of Fast Ironmaking at Low Temperature [D]. Beijing: Central Iron and Steel Research Institute, 2007 (in Chinese).
Author information
Authors and Affiliations
Corresponding author
Additional information
Foundation Item: Item Sponsored by National Natural Science Foundation of China (50474006); National Science and Technology Support Program for the 11th Five-Year Plan (2006BAE03A12, 2006BAE03A05)
Rights and permissions
About this article
Cite this article
Pang, Jm., Guo, Pm., Zhao, P. et al. Influence of size of hematite powder on its reduction kinetics by H2 at low temperature. J. Iron Steel Res. Int. 16, 7–11 (2009). https://doi.org/10.1016/S1006-706X(10)60002-7
Revised:
Published:
Issue Date:
DOI: https://doi.org/10.1016/S1006-706X(10)60002-7