METHOD FOR PRELIMINARILY TREATING MOLTEN PIG IRON

PROBLEM TO BE SOLVED: To inexpensively and reliably inhibit the foaming of the viscous slag which contains a high concentration of SiO2and is produced when molten pig iron is dephosphorized or desiliconized by a supplied oxygen source. SOLUTION: The preliminary treatment method for inhibiting the foaming of the slag 19 when preliminarily dephosphorizing or desiliconizing the molten pig iron 13 stored in a treatment vessel 2 while supplying the oxygen source to the molten pig iron includes adding a base metal 16 which has been collected from the slag produced during the dephosphorization treatment for the molten pig iron and has the slag bonded thereon, on the inner part of the treatment vessel during the preliminary treatment. In the step, it is preferable to control the content of CaO in the slag having bonded onto the base metal to 30 mass% or more, and to control a ratio of an iron content in the base metal having the slag bonded thereon to 30 mass% or more. COPYRIGHT: (C)2006,JPO&NCIPI