PROCESS OF REDUCING FINE-GRAINED IRON-CONTAINING MATERIAL BY MEANS OF SOLID CARBONACEOUS REDUCING AGENTS

摘要

Process of Reducing Fine-grained Iron-containing Material by Means of Solid Carbonaceous Reducing Agents Iron oxide containing materials and solid carbonaceous reducing agent are charged into a first expanded fluidized bed, which is supplied with an oxygencontaining fluidizing gas. The residence time selected for the gas in the reactor containing the first fluidized bed is so short that the reduction potential will result in a reduction not in excess of the FeO stage. The gassolids suspension discharged from the first fluidized bed is supplied to a second expanced fluidized bed, which is supplied with a strongly reducing fluidizing gas. Strongly reducing gas and a major portion of the resulting devolatilized carbonaceous material are discharged from the upper portion of the second fluidized bed. The devolatilized carbonaceous material is separated from the gas and recycled to the first fluidized bed. Part of the gas from the second fluidized bed is purified and treated for a removal of CO2 and is then recycled as fluidizing gas to the second fluidized bed. Reduced material having a metallization of 50 to 80 % and the remaining devolatilized carbonaceous material are discharged from the lower portion of the second fluidized bed. The rate at which devolatilized carbonaceous material is recycled from the upper portion of the second fluidized bed to the first fluidized bed is a multiple of the rate at which iron oxide containing materials are charged to the first fluidized bed. The heat content of the suspension transferred from the first fluidized bed to the second is used to supply the heat demand of the second fluidized bed.