METHOD FOR PREVENTING SLAG FOAMING AT THE TIME OF PRE-TREATING MOLTEN IRON

摘要

PURPOSE:To prevent slopping of slag at the time of pre-treating molten iron by controlling slag composition so that the foaming index defined with the specific formula becomes the specific value or less at the time of executing the pre-treatment of molten iron for dephosphorization and desulfurization. CONSTITUTION:In the pre-treatment of molten iron for dephosphorization or dephosphorization and desulfurization, the slag composition is controlled so that the foaming index (F.I) defined with the equation becomes =16. Then, at the time of controlling the F.I, (CaO)/(SiO2) control is executed such as adding lime before dephosphorizing treatment, controlling adding velocity of the lime or sufficiently removing desiliconized slag before dephosphorizing treatment, etc. By this method, flowing-out of the slag caused by the development of the foaming is prevented, and the stable operation and cost down are obtd.