Kinetics of magnetite oxidation under non-isothermal conditions

Aref Sardari; Eskandar Keshavarz Alamdari; Mohammad Noaparast; Sied Ziaedin Shafaei

doi:10.1007/s12613-017-1429-y

Volume 24 Issue 5

May 2017

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文章导航 > 矿物冶金与材料学报（英文） > 2017 > 24(5): 486-492

Aref Sardari, Eskandar Keshavarz Alamdari, Mohammad Noaparast, and Sied Ziaedin Shafaei, Kinetics of magnetite oxidation under non-isothermal conditions, Int. J. Miner. Metall. Mater., 24(2017), No. 5, pp. 486-492. https://doi.org/10.1007/s12613-017-1429-y

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Aref Sardari, Eskandar Keshavarz Alamdari, Mohammad Noaparast, and Sied Ziaedin Shafaei, Kinetics of magnetite oxidation under non-isothermal conditions, Int. J. Miner. Metall. Mater., 24(2017), No. 5, pp. 486-492. https://doi.org/10.1007/s12613-017-1429-y

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研究论文

Kinetics of magnetite oxidation under non-isothermal conditions

Department of Mining Engineering, Science and Research Branch, Islamic Azad University, Tehran 1477893855, Iran
Department of Mining and Metallurgical Engineering, Amirkabir University of Technology, Tehran 1591634311, Iran
School of Mining Engineering, University of Tehran, Tehran 515-14395, Iran

通讯作者:
Eskandar Keshavarz Alamdari E-mail: alamdari@aut.ac.ir

中文摘要

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.

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Research Article

Kinetics of magnetite oxidation under non-isothermal conditions

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Abstract

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.
- magnetite;
- kinetics;
- oxidation;
- thermogravimetric analysis

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References

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Kinetics of magnetite oxidation under non-isothermal conditions

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Kinetics of magnetite oxidation under non-isothermal conditions

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