Kinetics of magnetite oxidation under non-isothermal conditions

  • Aref Sardari
  • Eskandar Keshavarz Alamdari
  • Mohammad Noaparast
  • Sied Ziaedin Shafaei
Article
  • 88 Downloads

Abstract

Oxidation of magnetite concentrates, which occurs during the pellet induration process, must be deeply understood to enable the appropriate design of induration machines. In the present paper, the kinetics of the magnetite oxidation reaction was studied. Primary samples were obtained from the Gol-e-Gohar iron ore deposit. Magnetic separation and flotation decreased the sulfur content in the samples to be approximately 0.1wt%. Thermogravimetric analysis was used to measure mass changes during the oxidation of magnetite and, consequently, the conversion values. The aim of this study was to use isoconversional methods to calculate the kinetic parameters. The Coats–Redfern method was also used to obtain the activation energy. Thermogravimetric analyses were run at three different heating rates. The Coats–Redfern results were too ambiguous for a meaningful interpretation. In the case of the isoconversional method, however, the mean activation energy and pre-exponential factor of the oxidation reaction were obtained as 67.55 kJ and 15.32 × 108 min−1, respectively. Such a large activation energy implies that temperature strongly affects the reaction rate. The oxidation reaction exhibits a true multi-step nature that is predominantly controlled by chemical reaction and diffusion mechanisms.

Keywords

magnetite kinetics oxidation thermogravimetric analysis 

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References

  1. [1]
    M. Barati, Dynamic simulation of pellet induration in straight-grate system, Int. J. Miner. Process., 89(2008, No. 1–4), 30.CrossRefGoogle Scholar
  2. [2]
    T. Jiang, Y.B. Zhang, Z.C. Huang, G.H. Li, and X.H. Fan, Preheating and roasting characteristics of hematite–magnetite (H–M) concentrate pellets, Ironmaking Steelmaking, 35(2008, No. 1, 21.CrossRefGoogle Scholar
  3. [3]
    K. Meyer, Pelletizing of Iron Ores, Vol. 1, Springer-Verlog, Berlin, 1980.Google Scholar
  4. [4]
    B.P. Yurev and N.A. Spirin, Oxidation of iron-ore pellets, Steel Transl., 41(2011, 400.CrossRefGoogle Scholar
  5. [5]
    S.P.E. Forsmo, S.E. Forsmo, P.O. Samskog, and B.M.T. Björkman, Mechanisms in oxidation and sintering of magnetite iron ore green pellets, Powder Technol., 183(2008, No. 2, 247.Google Scholar
  6. [6]
    R. Liang, S. Yang, F.S. Yan, and J.C. He, Kinetics of oxidation reaction for magnetite pellets, J. Iron Steel Res. Int., 20(2013, No. 9, 16.CrossRefGoogle Scholar
  7. [7]
    E.R. Monazam, R.W. Breault, and R. Siriwardane, Kinetics of magnetite (Fe3O4) oxidation to hematite (Fe2O3) in air for chemical looping combustion, Ind. Eng. Chem. Res., 53(2014, No. 34, 13320.Google Scholar
  8. [8]
    S. Vyazovkin and C.A. Wight, Isothermal and non-isothermal kinetics of thermally activated reactions of solids, Int. Rev. Phys. Chem., 17(1998, No. 3, 407.CrossRefGoogle Scholar
  9. [9]
    S. Vyazovkin, K. Chrissafis, M.L.D. Lorenzo, N. Koga, M. Pijolat, B. Roduitf, N. Sbirrazzuoli, and J.J. Suñol, ICTAC Kinetics Committee recommendations for collecting experimental thermal analysis data for kinetic computations, Thermochim. Acta, 590(2014, 1.Google Scholar
  10. [10]
    S.P.E. Forsmo, Influence of Green Pellet Properties on Pelletizing of Magnetite Iron Ore [Dissertation], Lulea University of Technology, Lulea, 2007, p. 37.Google Scholar
  11. [11]
    A.W. Coats and J.P. Redfern, Kinetic parameters from thermogravimetric data, Nature, 201(1964, No. 4914, 68.CrossRefGoogle Scholar
  12. [12]
    J.A. Conesa, A. Marcilla, J.A. Caballero, and R. Font, Comments on the validity and utility of the different methods for kinetic analysis of thermogravimetric data, Pyrolysis J. Anal. Appl. Pyrol., 58-59(2001, 617.CrossRefGoogle Scholar
  13. [13]
    S. Vyazovkin, Isoconversional Kinetics of Thermally Stimulated Processes, Springer International Publishing, Switzerland, 2015.CrossRefGoogle Scholar
  14. [14]
    T. Kujirai and T. Akahira, Effect of temperature on the deterioration of fibrous insulating materials, Sci. Pap. Inst. Phys. Chem. Res., 2(1925, 223.Google Scholar
  15. [15]
    T. Ozawa, A new method of analyzing thermogravimetric data, Bull. Chem. Soc. Jpn., 38(1965, No. 11, 1881.CrossRefGoogle Scholar
  16. [16]
    J.H. Flynn and L.A. Wall, A quick, direct method for the determination of activation energy from thermogravimetric data, J. Polym. Sci. Part C, 4(1966, No. 5, 323.Google Scholar
  17. [17]
    ASTM, E1641: Standard Test Method for Decomposition Kinetics by Thermogravimetry, ASTM International, West Conshohocken, PA, 2004.Google Scholar
  18. [18]
    S.V. Vyazovkin and A.I. Lesnikovich, Estimation of the pre-exponential factor in the isoconversional calculation of effective kinetic parameters, Thermochim. Acta, 128(1988, 297.CrossRefGoogle Scholar
  19. [19]
    S. Vyazovkin, A.K. Burnham, J.M. Criado, L.A. Pérez-Maqueda, C. Popescu, and N. Sbirrazzuoli, ICTAC Kinetics Committee recommendations for performing kinetic computations on thermal analysis data, Thermochim. Acta, 520(2011, No. 1–2), 1.CrossRefGoogle Scholar
  20. [20]
    J. Hillier, T. Bezzant, and T.H. Fletcher, Improved method for the determination of kinetic parameters from non-isothermal thermogravimetric analysis (TGA) data, Energy Fuels, 24(2010, No. 5, 2841.CrossRefGoogle Scholar
  21. [21]
    R. Ebrahimi-Kahrizsangi and M.H. Abbasi, Evaluation of reliability of Coats–Redfern method for kinetic analysis of non-isothermal TGA, Trans. Nonferrous Met. Soc. China, 18(2008, No. 1, 217.Google Scholar
  22. [22]
    M.E. Brown, M. Maciejewskib, S. Vyazovkinc, R. Nomend, J. Sempered, A. Burnhame, et al., Computational aspects of kinetic analysis: Part A. The ICTAC kinetics project-data, methods and results, Thermochim. Acta, 355(2000, No. 1–2), 125.CrossRefGoogle Scholar
  23. [23]
    J.E. House, Principles of Chemical Kinetics, 2nd Ed., Vol. 1, Academic Press, Burlington, 2007.Google Scholar

Copyright information

© University of Science and Technology Beijing and Springer-Verlag Berlin Heidelberg 2017

Authors and Affiliations

  • Aref Sardari
    • 1
  • Eskandar Keshavarz Alamdari
    • 2
  • Mohammad Noaparast
    • 3
  • Sied Ziaedin Shafaei
    • 3
  1. 1.Department of Mining Engineering, Science and Research BranchIslamic Azad UniversityTehranIran
  2. 2.Department of Mining and Metallurgical EngineeringAmirkabir University of TechnologyTehranIran
  3. 3.School of Mining EngineeringUniversity of TehranTehranIran

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