| 摘要 |
PURPOSE:To make possible the constant blowing of pig for a casting and pig for steel making at a low cost in the same blast furnace by obtaining molten irons contg. silicon respectively at different ratios from the regions where the reduction or oxidation of the silicon component in the molten iron in the blast furnace progresses differently. CONSTITUTION:Iron ore 9 and fuel 10 are fed into the blast furnace 6. Pig iron particles 5 formed in a melting position 1 and gaseous SiO 4 formed by the reduction of SiO2 are brought into contact with each other in a dropping zone 3 so that Si is added to the molten iron by the reaction SiO+C Si+CO. The height of the zone 3 from a molten slag surface 2 is controlled by the amt. of the above-mentioned fuel 10 to be fed to the blast furnace 6 in the above-mentioned operating method by which the above-mentioned height in a position 7 for refining the pig for casting is increased and the height is decreased in a position 8 for refining the pig for steel making. The above- mentioned reduction reaction is thereby accelerated in the position where the height of the zone 3 is high and the pig iron for casting contg. Si at a high ratio is obtd.
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