DEPHOSPHORIZATION METHOD OF MOLTEN IRON AND PRODUCTION METHOD OF MOLTEN STEEL

To provide a dephosphorization method of molten iron and a production method of molten steel in which slags generated in refining processes are recycled.SOLUTION: In a dephosphorization method of molten iron, when the molten iron is charged into a vessel and oxygen is blown by adding a refining agent to dephosphorize the molten iron, decarburized slags generated in oxygen blowing for producing molten steel from the hot molten charged in the previous charge are left in the vessel. As a coolant, solidified slags generated in dephosphorization treatment of molten iron, cooled and solidified are used. Disclosed is a method for producing molten steel, which comprises a first process in which molten iron or molten iron and a source of cold iron are charged into a vessel and desiliconized and dephosphorized, a second process in which generated slags are discharged from the vessel, a third process in which a refining agent is added into the vessel and oxygen is blown to perform decarbonization and dephosphorization, and a fourth process in which the slags generated in the process are left in the vessel and cooled and solidified. In the production method, as a coolant of the slags left in the vessel, solidified slags discharged in the second process of the previous charge prior to the present charge, cooled and solidified are used.SELECTED DRAWING: Figure 1 【課題】精錬過程で生成するスラグを再利用する溶銑の脱燐方法および溶鋼の製造方法を提案する。【解決手段】容器内に溶銑を装入し、精錬剤を添加して酸素吹錬し溶銑を脱燐するに当たり、当該チャージの前チャージの溶銑から溶鋼を製造する酸素吹錬において発生した脱炭スラグを容器に残し、その冷却材として、溶銑の脱燐処理において発生した後、冷却し固化させておいた固化スラグを用いる溶銑の脱燐方法である。容器内に溶銑または溶銑と冷鉄源を装入し、脱珪脱燐処理を行う第一の工程と、発生したスラグを容器から排出する第二の工程と、容器内に精錬剤を添加して酸素吹錬し、脱炭脱燐を行う第三の工程と、その工程で発生したスラグを容器に残して冷却し固化させる第四の工程と、を有し、容器内に残したスラグの冷却材として、当該チャージより過去のチャージの第二の工程で排出して冷却し固化させておいた固化スラグを用いる溶鋼の製造方法である。【選択図】図１