| In order to investigate relationship between characteristics of pore texture such as porosity, diameter and shape factors and reduction behaviors of ferric oxide pellets, pore texture of pellets reduced with H₂ and CO gas at 700-900℃ were analysed with image analysis system. Reduction rate of H₂ gas was faster than that of CO gas. It was confirmed that reduction behaviors with H₂ gas could be analysed by the intermediate model, but that one with CO gas could be analysed by the unreacted core model. Porosity of pellets in the Fe₂O₃→Fe₃O₄ reduction stage was increased, but that of the Fe₃O₄→FeO and FeO→Fe was gradually decreased. In each reduction stage, porosity was decreased in the temperature range from 700℃ to 900℃, and this decrease of porosity was greater in the reduction by H₂ gas than that by CO gas. Mean diameter of pore was increased with proceeding of the reduction stage and was the biggest in the Fe₃O₄→FeO stage. In each reduction stage, porosity was decreased with the increase of temperature. Shape of pores such as roundness, aspect ratio and fullness ratio was rapidly worsened in the Fe₂O₃→Fe₃O₄ stage, but gradually improved in the reduction stage from magnetite to metal iron. |
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