METHOD FOR REFINING HOT PIG IRON

摘要

PROBLEM TO BE SOLVED: To provide a technique for manufacturing a high purity steel from hot pig iron having a silicon concentration of 0.45 mass% or more efficiently at low cost.SOLUTION: A method includes a desiliconization process for conducting a desiliconization treatment by adding a desiliconization agent to a blast furnace molten iron having a silicon concentration of 0.45 mass% to make a silicon concentration of 0.2 mass% to 0.4 mass%, a desulfurization process for conducting a desulfurization treatment by adding a desulfurization agent to the molten pig iron after the desiliconization treatment and a dephosphorization process for conducting a dephosphorization treatment by injecting the molten pig iron after the desulfurization treatment and adding a dephosphorization agent to suppress FeO contained in a desiliconization slag before the desulfurization treatment to 16 mass% or less.SELECTED DRAWING: Figure 1