| 摘要 |
PROBLEM TO BE SOLVED: To provide a hot metal pre-treatment method by which a hot metal suitable for refining a molten steel having excellent dephosphorizing oxygen efficiency and the phosphor concentration of <=200 ppm can be fed without using fluorite or chloride of an alkali metal. SOLUTION: In the hot metal pre-treatment method in which a refining agent is added to the hot metal held with a converter having a top-bottom blowing function of the gas, and the hot metal is dephosphorized by agitating the hot metal with the gas blown from a tuyere of the converter bottom while top-blowing oxygen gas, sintered ore of the grain size of 2-5 mm is used for a part of the refining agent by >=20 kg/t, and the oxygen quantity of the sintered ore brought in the hot metal is limited in a predetermined range so as to satisfy the range of the ratio of the sintered ore to oxygen defined by the inequalities of 30%<=A/(A+B)×100<=60%, wherein A/(A+B)×100 is the ratio (%) of sintered ore to oxygen, A (=unit consumption of sintered ore (kg/t)×0.17) is the oxygen content in sintered ore, and B (=unit consumption of gaseous oxygen (m3 standard condition/(t)) is the quantity of gaseous oxygen blown in hot metal).
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