METHOD FOR ADDING SLAG REFORMING AGENT IN CONVERTER

PURPOSE:To prevent the debasement in the compsn. of a molten metal by the effect of a carbon content and oxygen content by adding simultaneously CaCO3 or MgCO3 in the stage of adding a carbon-contg. material and oxygen-contg. material to molten slag to convert the characteristics of the molten slag during converter operation. CONSTITUTION:The carbon-contg. material is added to the molten slag to reduce the P2O5 in the molten slag and to produce a high-p steel during the converter operation. The oxygen-contg. material such as mill scale is otherwise added thereto to increase the O2 potential of the molten slag, thereby accelerating the oxidation dephosphorization of the molten metal. There is possibility of the direct effect of these additions on the molten steel resulting in the carburization of the molten steel or the increase of (O2) in the molten steel in such a case. The material such as CaCO3 or MgCO3 which generates CO2 at a high temp. is added to the molten slag in order to prevent such possibility. CaO and MgO are uniformly dispersed into the molten slag by the thermal decomposition thereof, by which the reaction boundary area is increased. The deviation of the content of C, P, etc. in the molten steel from the target value by the effect of the carbon-contg. material and oxygen-contg. material is thus prevented.