| 摘要 |
PROBLEM TO BE SOLVED: To provide an operating method for blowing pulverized fine coals into the blast furnace, in which the formation of a raceway shell is repressed and the pulverized fine coals having >=180 kg/ton of molten iron is stably blowed. SOLUTION: An upper limit of a charging rate of an ash accompanied with the pulverized fine coals, is decided according to the operational conditions of the blast furnace by following five factors. The factors are composed of a melting point and a viscosity of dripped slag 10, a charging rate into the peripheral wall of the raceway 6 a melting point and viscosity of the ash contained in the pulverized fine coals. The kind of the coals used is selected so that the charging rate of the ash into the raceway 6 is not over the upper limit. Preferably, the kind of the coal is selected so as to satisfy the following inequality 38.2>Vpc/S (Rash/100); wherein, Vpc: the blowing rate of the pulverized fine coals (kg/hr), S: the area of a furnace belly part (m2), Rash: the ash content in the pulverized fine coal (wt.%). The slag ratio in the blast furnace is made to 280-265 kg/ton of molten iron.
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