Softening behaviors of acid and olivine fluxed iron ore pellets in the cohesive zone of a blast furnace

Antti Kemppainen, Ko Ichiro Ohno, Mikko Iljana, Olli Mattila, Timo Paananen, Eetu Pekka Heikkinen, Takayuki Maeda, Kazuya Kunitomo, Timo Fabritius

    研究成果: ジャーナルへの寄稿学術誌査読

    45 被引用数 (Scopus)


    A ferrous burden loses its permeability in the cohesive zone of a Blast Furnace (BF) which has an effect on the flow of reducing gases. Iron ore pellets with various chemical compositions have different softening properties. Due to the occurrence of numerous simultaneous phenomena the clarification of different variables is difficult. In this study the effect of Reduction Degree (RD) on the softening behavior of individual acid and olivine fluxed iron ore pellets was experimentally tested under inert conditions. The acid pellet softened rapidly at 1 150°C and reached about 40% contraction at 1 200°C. The olivine fluxed pellet softened gradually in the range of 1 150 and 1 350°C and reached 30-35% contraction. The RDs of 50-70% for acid and 50-65% for olivine fluxed pellet had no significant effect on the softening behavior. However, the highest contraction-% was reached with the lowest RD. The results indicate that softening of the pellets is caused by the softening of the pellet core. The early softening of the acid pellet was attributed to high SiO2 content and formation of fayalite slag with high wüstite solubility. The superior properties of the olivine fluxed pellet were attributed to the low SiO2 content and favorable effects of fluxes to prevent wüstite dissolution. FactSage V6.4 -software and its FToxid-database was used to compute the phase equilibrium of a pre-reduced pellet with a quaternary FeO-SiO2-CaO-MgO system in the core region. The computed phase equilibrium provided additional information about the effects of different components in the phase equilibrium.

    ジャーナルisij international
    出版ステータス出版済み - 2015

    !!!All Science Journal Classification (ASJC) codes

    • 材料力学
    • 機械工学
    • 金属および合金
    • 材料化学


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