Effect of Iron Ore Size on Kinetics of Gaseous Reduction
Heung Won Kang, Won Sub Chung, Takeaki Murayama
In order to investigate the size effect on the kinetics of the gaseous reduction of iron ore, two kinds of iron oxide pellets of different diameters were reduced with CO-CO2 gas mixture. Results were analysed using two models, Ishida-Wen's model and the unreacted-core model. From the analysis of the former model, the intraparticle diffusivity through the product layer Ds, the intraparticle diffusivity in the reactant zone Dso and the chemical reaction rate constant based on volume kv were not changed with the particle diameter while Thiele's modulus φ and the effectiveness factor Ef were changed. From that of the latter model, the intraparticle diffusivity through the product layer De was not varied with the particle diameter, while the interface chemical reaction rate constant kc was varied. Further investigation revealed that kc was affected by the diffusion resistance through the product layer, that is, Ds and the particle size as well as the intraparticle diffusivity in the reactant zone and the reactivity.
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