| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for preliminary-treatment of molten iron which especially and sufficiently improves a dephosphorization efficiency at low cost. SOLUTION: When the preliminary-treatment is performed to the molten iron by supplying treatment agent into the molten iron charged into a treatment vessel through a lance, at the timing when P concentration in the molten iron becomes in the range exceeding 0.080%, it is controlled to be≤800 mm the dipping depth of the lance and≥10% ratio of the gaseous oxygen amount occupied in the total oxygen supplying amount, and thereafter, at the timing when the P concentration in the molten iron becomes≤0.080%, the dipping depth of the lance is adjusted to the position exceeding 800 mm. COPYRIGHT: (C)2004,JPO
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