MOLTEN IRON PRELIMINARY TREATMENT METHOD

• Main Authors: SUZUKI YOSHIO, SAITO KOSUKE, YOSHIDA ATSUHIKO
• Format: Patent
• Language: English; Japanese
• Published: 13.10.2016
• Subjects: CHEMISTRY; METALLURGY; METALLURGY OF IRON; PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OFWROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS

PROBLEM TO BE SOLVED: To provide a molten iron preliminary treatment method capable of removing metal adhering to a furnace wall while suppressing the occurrence of refractory erosion in a molten iron preliminary treatment furnace.SOLUTION: A molten iron preliminary treatment method for desiliconizing and decarbonizing a molten iron M in a converter type molten iron preliminary treatment furnace 1 by using a top-blown lance 2 having n pieces of nozzles arranged obliquely downward at approximately equiangular interval in a tip vertically directed downward and an agitating mechanism 3 caused by the discharge of inert gas comprises the steps of: forming a slag S including CO gas along the furnace wall 1a of the preliminary treatment furnace 1 together with the desiliconizing and decarbonizing; and melting a metal B formed in the furnace wall 1a of the preliminary treatment furnace 1 by the combustion of CO gas in the slag S. The molten iron surface collision pressure of the oxygen gas G of the top-blown lance 2 in the slag S formation step is 1600-6500 Pa, and the molten iron surface collision pressure of the oxygen gas G of the top-blown lance 2 in the metal melting step is 200-1200 Pa.SELECTED DRAWING: Figure 1 【課題】溶銑予備処理炉内の耐火物溶損の発生を抑止しつつ、炉壁に付着した地金を除去できる溶銑予備処理方法の提供。【解決手段】鉛直下方を向く先端に斜め下方かつ略等角度間隔で配設されるｎ個のノズルを有する上吹きランス２と、不活性ガスの吐出による撹拌機構３とを用い、転炉型溶銑予備処理炉１の溶銑Ｍへの脱珪及び脱炭処理を行う溶銑予備処理方法であって、上記脱珪及び脱炭処理と共にＣＯガスを含むスラグＳを予備処理炉１の炉壁１ａに沿って形成する工程と、予備処理炉１の炉壁１ａに形成される地金ＢをスラグＳ中のＣＯガスの燃焼により溶解する工程とを備えており、スラグＳ形成工程における上吹きランス２の酸素ガスＧの溶銑面衝突圧力が１６００〜６５００Ｐａ、上記地金溶解工程における上吹きランス２の酸素ガスＧの溶銑面衝突圧力が２００〜１２００Ｐａである溶銑予備処理方法。【選択図】図１