| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for operating a blast furnace, by which a hardly reducible lump ore is charged into the center or a middle part of the blast furnace at a lower part of an ore layer, where the reducing power is high, thereby reducing the amount of a reducing material to be used.SOLUTION: A method for operating a blast furnace comprises: delivering an ore material to the blast furnace by a plurality of delivery means, from one delivery means to another, the ore material prepared by cutting out a sintered ore, a lump ore and an auxiliary reducing material from corresponding reservoirs and stacking them; and alternately charging the ore material and coke into the blast furnace, thereby alternately forming ore material layers and coke layers in the furnace. Here, the grain size of the lump ore is adjusted so that the relation between the average grain size ratio (lump ore/sintered ore) Y of the lump ore to the sintered ore and the true density ratio (lump ore/sintered ore) X of the lump ore to the sintered ore falls within a prescribed relation range, thereby charging the lump ore into the center or a middle part in the radial direction of the blast furnace at a lower part of an ore material layer. |
