| 摘要 |
PURPOSE:To manufacture molten pig iron from iron ore with superior heat efficiency and reduction ratio, by stepwise moving and raising coal fluidized bed in a prereducing furnace having large ratio of height to diameter, lowering iron ore fines in the layer to prereduce, then charging into a melting furnace to melt and reduce by oxygen. CONSTITUTION:Coal in a hopper 18 is charged from a coal charging pipe 13 at bottom of the long, this and vertical prereducing furnace 11 having >=5 ratio of height/diameter by using an injection feeder 17 and with furnace top gas in which dust is removed by cyclones 22, 23 and pressure is raised by a pump 25 after passing through a heat exchanger 24. Simultaneously, high temp. air heated by the exchanger 24 is blown, coal is burnt fluidizedly, converted to char to form ascendant fluidized bed composed of a gas layer 31 and a char particle layer 32. The iron ore fines 19 are thrown from upper part of the furnace 11, prereduced while descending in fluidized bed and fed into a furnace 12 from a taking out hole 26. At the furnace 12, oxygen is jetted from an oxygen jetting pipe 27, heating, melting and reduction are carried out to form molten pig iron and slag, and molten pig iron is manufacture from iron ore fines with good heat efficiency and reduction ratio.
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