Kinetics and reaction mechanism of isothermal oxidation of Iranian ilmenite concentrate powder |
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Authors: | M Mozammel S K Sadrnezhaad A Khoshnevisan H Youzbashizadeh |
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Institution: | 1. Department of Materials Science and Engineering, Sharif University of Technology, Azadi Avenue, P.O. Box 11155-9466, Tehran, Iran
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Abstract: | Thermal oxidation of commercial ilmenite concentrate from Kahnouj titanium mines, Iran, at 500–950 °C was investigated for the first time. Fractional conversion was calculated from mass change of the samples during oxidation. Maximum FeO to Fe2O3 conversion of 98.63 % occurred at 900 °C after 120 min. Curve fit trials together with SEM line scan results indicated constant-size shrinking core model as the closest kinetic mechanism of the oxidation process. Below 750 °C, chemical reaction with activation energy of 80.65 kJ mol?1 and between 775 and 950 °C, ash diffusion with activation energy of 53.50 kJ mol?1 were the prevailing mechanisms. X-ray diffraction patterns approved presence of pseudobrookite, rutile, hematite, and Fe2O3·2TiO2 phases after oxidation of ilmenite concentrate at 950 °C. |
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