Abstract: A molten iron refining method having, an auxiliary material, and an oxidizing gas supplied through a top-blowing lance, to a cold iron source and molten pig iron that are contained/fed in a converter-type vessel, and molten iron is subjected to a refining process. A pre-charged cold iron source is charged into the converter-type vessel at an amount not larger than 0.15 times. A furnace-top-added cold iron source that's part or all of the cold iron source and added from a furnace top is fed during the refining process. A burner at a leading end of the top-blowing lance that spray holes through which a fuel and a combustion-supporting gas are ejected. During the refining process, a powdery auxiliary material processed into powder that's part of the auxiliary material is blown in, to pass through a flame formed by the burner.

Abstract: A converter steelmaking method has molten pig iron subjected to dephosphorization process for dephosphorized molten iron, dephosphorized molten iron is subjected to decarburization process for molten steel. For dephosphorization process, a first cold iron source in amount meeting Formula (1) is charged into first converter-type vessel, then undephosphorized molten pig iron is charged and subjected to dephosphorization process. Dephosphorized molten iron is discharged and held in molten metal receiving vessel. After second cold iron source is charged into first converter-type vessel in which dephosphorization process has been performed, the dephosphorized molten iron held in molten metal receiving vessel is charged and subjected to decarburization process. % Ws0?0.1186T?134 (% Ws0?0) . . . (1), where % Ws0: a ratio (%) of first cold iron source to sum of first cold iron source and charge amount of undephosphorized molten pig iron, and T: a temperature (° C.) of undephosphorized molten pig iron.

Abstract: A molten iron refining method that prevents a cold iron source from remaining unmelted even under the condition of a high ratio of the cold iron source. An auxiliary material is added, and an oxidizing gas is supplied, to cold iron source and molten pig iron that are contained or fed in converter-type vessel, and molten iron is subjected to refining process. Prior to refining process, a pre-charged cold iron source that is charged all at once into the converter-type vessel before the molten pig iron is charged into the converter-type vessel is charged in an amount not larger than 0.15 times the sum of an amount of the pre-charged cold iron source and a charge amount of the molten pig iron, or is not charged. A furnace-top-added cold iron source that is added from a furnace top of the converter-type vessel is fed into converter-type vessel during refining process.