| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for effectively dephosphorizing molten pig iron for obtaining a large dispersing action of dephosphorizing agent into the molten pig iron and a high dephosphorizing efficiency because the effective elimination of a dead zone is obtained with the large stirring force of the molten pig iron in a mixer car. SOLUTION: In the method for dephosphorizing the molten pig iron, by which the dephosphorization is applied by blowing oxygen gas and the dephosphorizing agent composed of iron oxide, CaO-base flux, etc., together with carrier gas through immersion lances into the molten pig iron filled up in the mixer car, this dephosphorizing method to the molten pig iron is performed, with which two pieces of immersion lances inserted by directing the longitudinal direction in the pig iron ladle car, are dipped into the molten pig iron so as to be mutually faced, and the blowing of the dephosphorizing agent is performed under conditions satisfying the following (1)-(3) formulas from these lances. In the (1) formula, 0.5H<HL<0.9H, in the (2) formula, 50≤Qp/Qg and in the (3) formula, 0.10L≤W≤0.50L. In these formulas, HL: lance immersion depth (m) from statical molten metal surface, H: molten pig iron bath depth (m), Qp: solid dephosphorizing agent blowing velocity (kg/min), Qg: carrier gas flowing rate (m<SP>3</SP>(standard condition)/min), W: distance (m) between the tip parts of two immersion lances, L: the maximum distance (m) in the longitudinal direction of torpedo car. COPYRIGHT: (C)2005,JPO&NCIPI
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