| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for dephosphorizing molten pig iron, which can obtain high dephosphorization efficiency while keeping slag at a low degree of basicity, and simultaneously can inhibit spitting and dust from being produced and also an iron yield from decreasing. SOLUTION: In a dephosphorizing method of adding a refining agent containing a CaO source as a main component into the molten pig iron in a converter type container, and spraying gaseous oxygen onto the surface of the molten pig iron bath from the top-blowing lance, this dephosphorizing method includes setting the feed rate of the gaseous oxygen blown from the top-blowing lance at 1.5 to 5.0 Nm<SP>3</SP>/min/molten pig iron ton and treating the molten pig iron so that the slag basicity (%CaO/%SiO<SB>2</SB>) can be kept at 1.0 or more but less than 2.5 after the treatment. Preferably a powdery or granular solid oxygen source is sprayed onto the surface of the molten pig iron bath from the top-blowing lance. COPYRIGHT: (C)2009,JPO&INPIT
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