MOLTEN IRON PRELIMINARY TREATMENT METHOD

• Main Authors: SUZUKI YOSHIO, YOSHIDA ATSUHIKO
• Format: Patent
• Language: English; Japanese
• Published: 27.07.2017
• 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 bullion adhered to a wall surface of a molten iron ladle easily and surely.SOLUTION: The molten iron preliminary treatment method has a process for forming slag containing CO gas along a wall surface of a molten iron ladle and a process for dissolving a bullion adhered to the wall surface of the molten iron ladle by burning CO gas in the slag, wherein desiliconization amount (ΔSi) in the slag formation process is 0.1 mass% to 0.15 mass% of Si in the molten iron ladle before desiliconization, molten iron surface collision pressure of oxygen gas of a top-blown lance is 1000 Pa to 2000 Pa, stirring input energy of inert gas by a stirring mechanism is 100 W/t to 300 W/t and oxygen gas supplied amount to molten iron at desiliconization oxygen efficiency of ηsi[%] is 720×ΔSi/ηsi[Nm/t] to 850×ΔSi/ηsi[Nm/t].SELECTED DRAWING: Figure 4 【課題】溶銑鍋の壁面に付着した地金を容易かつ確実に除去することができる溶銑予備処理方法の提供を目的とする。【解決手段】本発明の溶銑予備処理方法は、ＣＯガスを含むスラグを溶銑鍋の壁面に沿って形成する工程と、上記スラグ中のＣＯガスの燃焼により上記溶銑鍋の壁面に付着した地金を溶解する工程とを備えており、上記スラグ形成工程における脱珪量（ΔＳｉ）が脱珪前の溶銑鍋中のＳｉの０．１ｍａｓｓ％以上０．１５ｍａｓｓ％以下、上吹きランスの酸素ガスの溶銑面衝突圧力が１０００Ｐａ以上２０００Ｐａ以下、撹拌機構による不活性ガスの撹拌投入エネルギーが１００Ｗ／ｔ以上３００Ｗ／ｔ以下、脱珪酸素効率をηｓｉ［％］とするときの溶銑への酸素ガス供給量が７２０×ΔＳｉ／ηｓｉ［Ｎｍ３／ｔ］以上８５０×ΔＳｉ／ηｓｉ［Ｎｍ３／ｔ］以下である。【選択図】図４