METHOD FOR OPERATING BLAST FURNACE AND METHOD FOR MANUFACTURING MOLTEN IRON

PROBLEM TO BE SOLVED: To provide a method for operating a blast furnace, capable of maintaining stable operation of a blast furnace with a sufficiently high iron tapping ratio.SOLUTION: The method for operating a blast furnace includes charging the blast furnace with raw material iron oxide, cokes, and partially reduced iron from the furnace top, and injecting fine coal and oxygen-enriched air from the tuyere of the blast furnace, so that the raw material iron oxide is reduced to molted iron. The method comprises: a first step of adjusting the charging amount of cokes while monitoring a furnace top temperature T; a second step of adjusting the injecting amount of the fine coal while monitoring a furnace superficial gas flow rate u and the furnace top temperature T; a third step of adjusting the oxygen enrichment ratio of the oxygen-enriched air while monitoring a combustion temperature Tof the tuyere and the furnace top temperature T; and a fourth step of determining the necessity for adjusting the injection amount of the oxygen-enriched air responding to the value of the furnace superficial gas flow rate u.