METHOD FOR PREVENTING SLAG FOAMING IN PRE-REFINING FOR MOLTEN IRON

摘要

PURPOSE:To prevent slag foaming with good efficiency by blowing gas nearby interface between molten iron and slag during charging pre-treating agent into molten iron in a reaction vessel. CONSTITUTION:A lance 2 is inserted into molten iron 5 contained in a torpedo car 1 and dephosphorizing agent 7 is blown from the tip part thereof to execute dephosphorization. This dephosphorizing agent 7 is ascended into molten iron and the slag foaming is developed with CO gas generated by reacting with oxidizing agent in the dephosphorizing agent and by supplying carrier gas for the dephosphorizing agent 7 in the slag 6. For this purpose, a gas injection hole 3 is arranged to the prescribed height H of a lance 2 and gas 8 for shifting slag is blown from this lance to near the interface between the molten iron and the slag at the prescribed angle thetaso as to hit against floating-up position of the carrier gas 7 for the dephosphorizing agent in the molten iron. By this method, the slag floated on the molten iron surface is pushed and shifted toward wall face direction of the torpedo car and opening hole part 10 from which the above carrier gas 7 is discharged into the air is formed. By this method, pre-refining treatment is not required to interrupt and the slag foaming can be prevented.