REFINING METHOD OF HOT METAL

PROBLEM TO BE SOLVED: To provide a refining method of hot metal capable of reducing the amount of quicklime newly added for Blow2 blowing after Blow1 blowing and subsequent deslagging.SOLUTION: In the refining method of hot metal according to the present invention, dephosphorized hot metal 14 is produced by Blow1 blowing in which a CaO source is added and oxygen is top-blown into molten pig iron 12 contained in a converter-type vessel 11, and Blow2 blowing is performed after formed slag 15 is discharged, in which oxygen is top-blown into the dephosphorized hot metal 14 with new addition of quicklime. An auxiliary raw material containing one or both of an ingot-making slag with CaO and quicklime is used as the CaO source, concentration of AlOis 3.5 mass% or more and 10 mass% or less, and basicity is 0.8 or more and 1.2 or less in the slag 15 after the Blow1 blowing, and deslagging of the slag 15 is performed after the Blow1 blowing so that a mass of the slag is reduced to the range between 50 mass% or more and 80 mass% or less, provided that a total mass of the slag 15 formed by the Blow1 blowing is 100 mass%.SELECTED DRAWING: Figure 1 【課題】Ｂｌｏｗ１吹錬後にスラグを排滓してＢｌｏｗ２吹錬を行うに際し、新たに添加する生石灰の添加量を従来よりも削減可能な溶銑の精錬方法を提供する。【解決手段】転炉型容器１１内の溶銑１２にＣａＯ源を添加して上吹き送酸するＢｌｏｗ１吹錬により脱Ｐ溶湯１４を溶製した後、生成したスラグ１５を排滓し、脱Ｐ溶湯１４に新たに生石灰を添加して上吹き送酸するＢｌｏｗ２吹錬を行う溶銑の精錬方法であり、ＣａＯ源として、ＣａＯを含む造塊スラグ及び生石灰のいずれか一方又は双方を含む副原料を用い、Ｂｌｏｗ１吹錬後のスラグ１５を、Ａｌ２Ｏ３濃度：３．５質量％以上１０質量％以下、塩基度：０．８以上１．２以下とし、Ｂｌｏｗ１吹錬後のスラグ１５の排滓を、Ｂｌｏｗ１吹錬で生成したスラグ１５の総質量を１００質量％として５０質量％以上８０質量％以下の範囲で行う。【選択図】図１