DESULFURIZING METHOD FOR MOLTEN STEEL

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PROBLEM TO BE SOLVED : To provide a desulfurizing method which can obtain desulfurizing effect equal to desulfurization using a slag with high Al and high CaO concentration, even when Al concentration in molten steel is low and CaO concentration in the slag is low, and also can obtain a desulfurizing rate higher than that of the conventional method when Al concentration and CaO concentration are equal to those of the convention method. SOLUTION : In the desulfurizing method, one or more of rare earth metal such as La, Ce, and Nd is added to the molten steel, then gas stirring is performed, in the refining treatment of stirring a molten steel in a ladle and a slug on a surface of the molten steel with an inert gas. The amount of the rare earth metal added is 0.2 kg/ton or more and 0.9 kg/ton or less. The amount of Al added before adding the REM is adjusted such that the ratio [Al]/[REM] of Al concentration [Al] (mass%) in the molten steel after desulfurizing treatment to a total concentration of the rare earth metals [REM] (mass%) in the molten steel is 1.2 or more and 20 or less. COPYRIGHT : (C)2012, JPO&INPIT