各種ヘマタイトペレット水素還元速度の多段反応帯モデルによる解析
1983 年 69 巻 6 号 p. 546-555
詳細
1983 年 69 巻 6 号 p. 546-555
Hydrogen reduction of various hematite pellets (firing temperature, 1 100°1 300°C; slag content, 010 wt%; basicity, (wt% CaO) / (wt% SiO2) = 02; total porosity, 0.050.45; reduction temperature, 800°1 000°C) is analyzed by using the multi-stage zone-reaction model (MSZR1 model) and that with solid-state diffusion of oxygen dissolved in iron (MSZR2 model).
In pellets having wüstite particles encircled with dense iron (particle E), reduction curves and boundary radii calculated by using MSZR2 model agree well with experimental data up to the final stage of reduction. In pellets having almost no particle E, such as the pellets of basicity 0.5, the results calculated by using MSZR1 model agree well with experimental data. It is quantitatively confirmed that the reduction rate in the final stage varies according to the amount and diameter of particle E and to reduction temperature.
Expressions for chemical-reaction rate-constants and effective diffusivities are presented as functions of temperature and porosity, respectively. Moreover, the analytical method for the hydrogen reduction of any hematite pellets is proposed; reduction curves for other pellets, such as Hamersley pellet and laboratory (acid and fluxed) pellets, are estimated well by this method.
