Reduction kinetics of MgO-doped calcium ferrites under CO–N2 atmosphere

  • Tian-xiong Wang
  • Cheng-yi DingEmail author
  • Xue-wei Lv
  • Sen-wei Xuan
  • Gang Li
Original Paper


The effect of magnesia on calcium ferrite (CaO·Fe2O3) reduction by CO was examined by isothermal thermogravimetry. Samples of calcium ferrite added with 0, 2, 4, and 8 wt.% magnesia (abbreviated as CF, CF2M, CF4M, and CF8M) were prepared. Phase composition was analyzed by X-ray diffraction, and the results indicated that CF2M and CF4M are reduced to lower reduction degree and with lower apparent activation energy than CF; and CF8M with more MgO·Fe2O3 is reduced to a lower degree and with more difficulty compared with CF. Reduction rate analysis revealed that CF, CF2M, CF4M, and CF8M reductions are all typical two-step reactions with the order of CF → CWF (CaO·FeO·Fe2O3) → Fe. The apparent reduction activation energies of CF, CF2M, CF4M, and CF8M are 46.89, 37.30, 17.30, and 29.20 kJ/mol, respectively. Sharp analysis depicted that CF2M, CF4M, and CF8M reductions are all described by 2D Avrami–Erofeev (A–E) equation (A2) in the whole process, while CF reduction is first expressed by A2 and then by 3D A–E equation (A3). Different from shrinking core model, a new kinetic model for powdery samples reduction was proposed to illustrate the relationship among reduction rates, reduction routes, and model functions.


Calcium ferrite Magnesia Reduction kinetics Reduction model 



The study was performed with the financial support of the National Natural Science Foundation of China (51234010 and 51522403), the Program for New Century Excellent Talents in University and the Program for the Youth Top-Notch Talents of Chongqing (20151001), Ultrasonic Assisted Iron Ore Sintering Technology Research (cstc2014kjrc–qnrc90001), and China Scholarship Council.


  1. [1]
    C. Ding, X. Lv, S. Xuan, K. Tang, C. Bai, ISIJ Int. 56 (2016) 2118–2125.CrossRefGoogle Scholar
  2. [2]
    C. Ding, X. Lv, S. Xuan, J. Qiu, Y. Chen, C. Bai, ISIJ Int. 57 (2017) 634–642.CrossRefGoogle Scholar
  3. [3]
    C. Ding, X. Lv, G. Li, C. Bai, S. Xuan, K. Tang, Y. Chen, ISIJ Int. 57 (2017) 1181–1190.CrossRefGoogle Scholar
  4. [4]
    S. Xuan, X. Lv, C. Ding, K. Tang, G. Li, G. Pei, S. Wu, Steel Res. Int. 89 (2018) 1700452.CrossRefGoogle Scholar
  5. [5]
    M.K. Kalenga, A.M. Garbers-Craig, J. South Afr. Inst. Min. Metall. 110 (2010) 447–456.Google Scholar
  6. [6]
    T. Li, C. Sun, X. Liu, S. Song, Q. Wang, Ironmak. Steelmak. 45 (2018) 755–763.CrossRefGoogle Scholar
  7. [7]
    J.H. Yao, J. Yang, D. Han, X.M. Guo, Iron and Steel 50 (2015) 12–16.Google Scholar
  8. [8]
    S. Xuan, X. Lv, K. Tang, C. Ding, G. Li, C. Bai, in: B. Li (Eds.), TMS Annual Meeting & Exhibition, Springer, Cham, 2018, pp. 121–129.Google Scholar
  9. [9]
    C. Ding, X. Lv, S. Xuan, X. Lv, G. Li, K. Tang, Adv. Powder Technol. 28 (2017) 2503–2513.CrossRefGoogle Scholar
  10. [10]
    E.T. Turkdogan, AlChE J. 23 (1977) 612.CrossRefGoogle Scholar
  11. [11]
    R.C. McCune, P. Wynblatt, J. Am. Ceram. Soc. 66 (1983) 111–117.CrossRefGoogle Scholar
  12. [12]
    W.F.K. Wynne-Jones, H. Eyring, J. Chem. Phys. 3 (1935) 492–502.CrossRefGoogle Scholar
  13. [13]
    S. Vyazovkin, C.A. Wight, Thermochim. Acta 340–341 (1999) 53–68.CrossRefGoogle Scholar
  14. [14]
    C. Ding, X. Lv, G. Li, C. Bai, S. Xuan, K. Tang, X. Lv, Int. J. Hydrogen Energy 43 (2018) 24–36.CrossRefGoogle Scholar
  15. [15]
    M.I. Nasr, A.A. Omar, M.H. Khedr, A.A. El-Geassy, ISIJ Int. 35 (1995) 1043–1049.CrossRefGoogle Scholar
  16. [16]
    B. Perrenot, G. Widmann, J. Therm. Anal. 37 (1991) 1785–1792.CrossRefGoogle Scholar
  17. [17]
    T. Wiltowski, C.C. Hinckley, G.V. Smith, T. Nishizawa, M. Saporoschenko, R.H. Shiley, J.R. Webster, J. Solid State Chem. 71 (1987) 95–102.CrossRefGoogle Scholar
  18. [18]
    M. Avrami, J. Chem. Phys. 7 (1939) 1103–1112.CrossRefGoogle Scholar
  19. [19]
    M. Avrami, J. Chem. Phys. 8 (1940) 212–224.CrossRefGoogle Scholar
  20. [20]
    M. Avrami, J. Chem. Phys. 9 (1941) 177–184.CrossRefGoogle Scholar
  21. [21]
    J.H. Sharp, G.W. Brindley, B.N.N. Achar, J. Am. Ceram. Soc. 49 (1966) 379–382.CrossRefGoogle Scholar
  22. [22]
    H.G. McAdie, Thermochim. Acta 1 (1970) 325–333.CrossRefGoogle Scholar
  23. [23]
    J.A. Allen, D.E. Scaife, J. Phys. Chem. 58 (1954) 667–671.CrossRefGoogle Scholar
  24. [24]
    J.L. Duda, J.S. Vrentas, Ind. Eng. Chem. Fundamen. 4 (1965) 301–308.CrossRefGoogle Scholar
  25. [25]
    C.Y. Wen, Ind. Eng. Chem. 60 (1968) 34–54.CrossRefGoogle Scholar
  26. [26]
    M. Ishida, T. Shirai, J. Chem. Eng. Jpn. 3 (1970) 196–200.CrossRefGoogle Scholar
  27. [27]
    Q.T. Tsay, W.H. Ray, J. Szekely, AlChE J. 22 (1976) 1064–1072.CrossRefGoogle Scholar

Copyright information

© China Iron and Steel Research Institute Group 2019

Authors and Affiliations

  • Tian-xiong Wang
    • 1
    • 2
  • Cheng-yi Ding
    • 1
    • 2
    Email author
  • Xue-wei Lv
    • 1
    • 2
  • Sen-wei Xuan
    • 1
    • 2
  • Gang Li
    • 1
    • 2
  1. 1.Chongqing Key Laboratory of Vanadium-Titanium Metallurgy and New MaterialsChongqing UniversityChongqingChina
  2. 2.School of Materials Science and EngineeringChongqing UniversityChongqingChina

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