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Kinetic Study For The Formation Of The Oxygendeficient Magnetite

Published online by Cambridge University Press:  15 February 2011

T. Togawa ,
Y. Wada ,
T. Yoshida ,
M. Tsuji  and
Y. Tamaura
T. Togawa
Affiliation:
Tokyo Institute of Technology, 2121, Ookayama, Meguroku, Tokyo, 152, Japan
Y. Wada
Affiliation:
Tokyo Institute of Technology, 2121, Ookayama, Meguroku, Tokyo, 152, Japan
T. Yoshida
Affiliation:
Tokyo Institute of Technology, 2121, Ookayama, Meguroku, Tokyo, 152, Japan
M. Tsuji
Affiliation:
Tokyo Institute of Technology, 2121, Ookayama, Meguroku, Tokyo, 152, Japan
Y. Tamaura
Affiliation:
Department of Chemistry, Research Center for carbon Recycling & Utilization
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Abstract

An oxygendeficient magnetite (Fe3O4–8) has been found to exist in the range of (0<Δ<0.12) in the course of H2-reduction of magnetite to αFe at 300°C. The formation of the oxygendeficient magnetite was studied kinetically. In the temperature range of 250 350°C, the rate constants, k1, and k2, were determined for the forward and reverse reactions, respectively. The rate of formation of the oxygendeficient magnetite depended on the partial pressure of H2 gas. The rate constant, k1, was 109.58 at 300°C and the reaction order was 1.11 with respect to the partial pressure of H2 gas. The rate of reverse reaction depended on the partial pressure H2O gas and the oxygen deficiency of magnetite, Δ. The rate constant of the reverse reaction, k2, was 10−2.54 at 300°C, and the reaction orders were 0.45 and 0.99 with respect to the partial pressure of H2O gas and the Δ value respectively. The activation energies for the forward and reverse reactions were determined to be 63.8 kJ.mol−1 and 25.5 kJ.mol−1 from the Arrhenius' equation.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 344: Symposium I – Materials and Processes for Environmental Protection , 1994 , 51
Copyright
Copyright © Materials Research Society 1994

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