| 摘要 |
PURPOSE: To provide a refining method capable of controlling content of phosphorus in molten steel and reducing erosion of refractories when refining the return molten steel by charging return molten steel into a converter again. CONSTITUTION: In a method for refining the return molten steel by charging burnt dolomite, hot metal and return molten steel into a converter, the method for refining return molten steel mixed hot metal in the converter comprises a step of obtaining a minimum CaO quantity required for refining phosphorus in the converter; a step of obtaining a burnt dolomite quantity for supplying the minimum CaO quantity; a step of obtaining a T.Fe quantity in slag at a terminal point of the converter; a step of obtaining a MgO solubility content by converting the T.Fe quantity in slag into an iron oxide(FeO) quantity; a step of obtaining a slag generation amount from the burnt dolomite quantity and predicted slag constituents; a step of obtaining a MgO concentration in slag by using the minimum burnt dolomite injection quantity and the slag generation amount; a step of determining the burnt dolomite quantity as a substantial injection quantity if the MgO concentration in slag is greater than the MgO solubility content by comparing the MgO concentration in slag with the MgO solubility content, repeating a step of comparing the MgO concentration in slag with the MgO solubility content after obtaining MgO concentration in slag again while adding quantity of burnt dolomite to the burnt dolomite quantity value until the MgO concentration in slag is greater than the MgO solubility content if MgO concentration in slag is less than the MgO solubility content, and determining a value obtained by summing up the burnt dolomite quantity value and the added burnt dolomite quantity as the substantial injection quantity; and a step of injecting the determined substantial injection quantity of burnt dolomite into the converter.
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