| 摘要 |
PROBLEM TO BE SOLVED: To increase a compounding ratio of a cold iron source in molten iron stably when performing the oxidizing refining of hot metal by forming flame at the lower end of a top-blowing lance and, while heating a powdery refining agent with this flame, spraying it to the hot metal in a converter to which the cold iron source is added.SOLUTION: Flame is formed in front of a nozzle of a top-blowing lance 3 toward a bath surface of hot metal 26 accommodated into a converter. While a powdery refining agent 29 is heated with this flame and sprayed toward the bath surface of the hot metal 26, oxidizing gas for refining is supplied toward the bath surface of the hot metal 26 from a supply path for the oxidizing gas for refinement. The flame is formed while satisfying formula (1): 0.4≤(G/F)/(G/F)≤1.0. In formula (1), G represents supply speed of oxidizing gas for combustion (Nm/min), F represents fuel gas supply speed (Nm/min), and (G/F)represents the ratio of stoichiometric coefficients of the fuel gas and the oxidizing gas for combustion required for complete combustion of the fuel gas. |
