The microstructures of porous magnetite formed on gaseous reduction of dense hematite have been examined using high-resolution scanning electron microscopy. It has been shown that cellular pores are formed on reduction in the temperature range 573 K to 973 K (300 °C to 700 °C). Dendritic shaped gas pores are formed on reduction at temperatures between 1073 K and 1273 K (800 °C and 1000 °C). The apparent chemical reaction rate constant for the reduction of hematite to magnetite in CO/CO2 gas mixtures has been derived from measurements of product thickness against reaction time; the rate constant is described by the relation φCO = 0.232exp(76,000/RT) µm s−1 atm−1.

中文翻译：

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CO/CO2 气氛中赤铁矿还原为磁铁矿的微观结构变化和动力学

已使用高分辨率扫描电子显微镜检查了致密赤铁矿气态还原形成的多孔磁铁矿的微观结构。已经表明，在 573 K 至 973 K（300 °C 至 700 °C）的温度范围内还原时会形成细胞孔。在 1073 K 至 1273 K（800 °C 至 1000 °C）的温度下还原时会形成树枝状气孔。赤铁矿在 CO/CO2 气体混合物中还原为磁铁矿的表观化学反应速率常数来自于对反应时间的产物厚度测量；速率常数由关系 φCO = 0.232exp(76,000/RT) µm s−1 atm−1 描述。