| 摘要 |
PROBLEM TO BE SOLVED: To attain a reduced fuel ratio and improved productivity in a blast furnace by ensuring the reducibility of sintered ore when its alumina (Al<SB>2</SB>O<SB>3</SB>) content is high and raising the O/C ratio, i.e, ore/coke ratio, around the periphery of the furnace when a large amount of pulverized coal is blown into the furnace to improve a reduction efficiency in this zone. SOLUTION: The reducibility of the sintered ore is kept good by adjusting the amount of a high-alumina-containing iron ore added to a raw material for the production of the sintered ore so as to adjust the alumina content in the sintered ore to below 1.70 wt.%. Separately, the high-alumina-content iron ore removed from the raw material for producing the sintered ore is reduced to produce a lumpy or powdery reduced iron ore having a reduction rate of 50 to below 95%. The lumpy reduced ore is charged into the blast furnace from its top, while the powdery reduced ore is blown into the furnace from its tuyere. COPYRIGHT: (C)2006,JPO&NCIPI
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