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AssigneeJfe Steel Corporation
InventorsShizuhiko Ikeno, Yozo Iwaki, Naotaka Sasaki, Takeshi Ishii, Yuichi Uchida, Masanori Nishikori
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In a molten iron refining method by charging molten iron and a cold iron source into a converter type refining vessel, supplying a material containing CaO with an oxygen source dissolving the cold iron source and conducting molten iron desiliconization, removing at least a part of the produced slag as an intermediate slag removal, and supplying a slag-forming agent and an oxygen source to the molten iron for dephosphorization, a silicon-containing material or a combination of it and carbonaceous material is added in the desiliconization then carried out under conditions such that the slag basicity (mass % CaO/mass % SiO2) in the desiliconization completion is more than 0.5 but less than 1.5 and a molten iron temperature in the desiliconization completion is more than 1280° C. but less than 1350° C. and more than 30 mass % of the slag produced in the desiliconization is removed from the vessel in the intermediate slag removal.
A method of refining molten iron by charging molten iron and a cold iron source into a converter type refining vessel, supplying an auxiliary material containing CaO as a main component together with an oxygen source to dissolve the cold iron source and at the same time conduct desiliconization of the molten iron, removing at least a part of slag produced by the desiliconization as an intermediate slag removal, and subsequently supplying a slag-forming agent and an oxygen source to the molten iron in the converter type refining vessel to conduct dephosphorization, characterized in that a silicon-containing material or a combination of a silicon-containing material and a carbonaceous material is added as a heat source to the converter type refining vessel in the desiliconization and then the desiliconization is carried out under conditions that a basicity of the slag (mass % CaO/mass % SiO2) in the completion of the desiliconization is not less than 0.5 but not more than 1.5 and a molten iron temperature in the completion of the desiliconization is not lower than 1280° C. but not higher than 1350° C. and then not less than 30 mass % of the slag produced in the desiliconization is removed from the converter type refining vessel in the intermediate slag removal.
Dependencies are inferred from the claim text.