DECARBONIZATION REFINING METHOD OF DESPHOSPHORIZED AND DESULFURIZED IRON

摘要

PURPOSE:To eliminate the occurrence of slopping at the blowing and improve the yield of steel making by using the desiliconized, desulfurized and dephosphorized molten iron for raw material iron at the time of refining steel through molten metal stirring by gas blowing from furnace bottom and oxygen top blowing. CONSTITUTION:Molten iron for steel making raw material is oxygen-refined with alkali metal compounds such as Na2CO3 as flux, whereby its Si, S and P are removed into the molten slag. This molten iron is separated from the molten slag and is charged into an oxygen top blowing converter. While the molten metal is being stirred by blowing inert gas such as Ar or N2 or oxidative gas such as oxygen or air from the converter bottom, the molten iron is subjected to oxygen top blowing refining. Since this refining is the decarbonization refining only, no slag exists, hence no slopping phenomenon occurs and there is no loss of molten steel. The oxygen blowing partially forms FeO and MnO but these are reduced by the C in the molten steel and their amount is extremely small.