| 摘要 |
PROBLEM TO BE SOLVED: To achieve the lowering of fuel ratio and the improvement of production in a blast furnace by securing the reducibility of a sintered ore, raising an O/C ratio at the peripheral part of the furnace and improving the reducing efficiency in this zone when a large quantity of pulverized fine coal is blown in. SOLUTION: In an operational method of the blast furnace, by which the pulverized fine coal is blown from a tuyere part of the blast furnace, and also, iron raw material and carbonaceous material are charged from the furnace top part of the blast furnace, the high reducible sintered ore containing <5 wt.% SiO2, <1 wt.% MgO and <1.8 wt.% Al2O3 and having 1.8-2.5 basicity (CaO/SiO2) is charged from the furnace top part of the blast furnace, or in addition, together with the highly reducible sintered ore, massive iron ore having high content of Al2O3 and 10-35 mm grain diameter, is pre-mixed therewith and charged, or the powdery iron ore having high content of Al2O3 and <5 mm grain diameter is blown from the tuyere part of the blast furnace to adjust the Al2O3 content in slag flowing out from an iron tapping outlet of the blast furnace to 13-16 wt.%.
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