Carbothermic reduction of iron oxide is an attractive mechanism to produce metallic iron, since it can directly utilise coal as both reductant and fuel. To improve energy efficiency and productivity of the metallic ron production based on this mechanism. the combustion bed process packed with the composites of iron oxide and coal powder was experimentally evalauted. The process has a potential of high heat efficiency since it can automatically utilise the heat of reduced materials as that necessary to the subsequent reduction of the composite by a large heat exchange rate between the packed particles and gas flowed across the bed. However, it is hard to perfectly prevent the reoidation of formed metallic iron in the bed. The present paper reports the effect of coal content, pelelt size and so forth on the reduction/metallisation degrees of the samples after the reduction experiemnt. It also discusses the effect of pretreatment of the composite pellets using CaO bearing mateirals to suppress the reoxidation of formed metallic iron in the bed.
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