| 摘要 |
PURPOSE:To elevate a dephosphorizing effect without dropping the yield of Fe, by blowing carbon powder and oxygen gas into molten steel under the existence of high basic slags, and bubbling molten slags so that they are discharged easily, when steel is manufactured and refined by an arc furnace. CONSTITUTION:When steel is refined by an arc furnace, high basicity slags whose basicity CaO/SiO2 is >=2 are generated by adding a flux such as CaO, CaF2, etc. Also, carbon powder is blown into molten steel together with oxygen gas by a lance, the carbon powder reacts with oxygen in the molten steel or the molten slag, and a great deal of gaseous CO is generated. By this gaseous CO, a foaming layer is formed in the molten slag and swells, its fluidity is elevated, and it is discharged easily out of the furnace. Accordingly, a phosphorous portion removed in the form of phosphoric acid lime in a high basic slag is discharged, is dephosphorized effectively without being rephosphorized in the molten steel, also the molten steel is oxidized at a high temperature, and the yield does not drop. |
