IMMERSION TYPE LANCE INSTALLATION FOR PRELIMINARY TREATMENT OF MOLTEN IRON AND GAS SWITCHING METHOD FOR IMMERSION TYPE LANCE FOR PRELIMINARY TREATMENT OF MOLTEN IRON

摘要

PROBLEM TO BE SOLVED: To provide an immersion type lance for preliminary treatment of molten iron which allows grasping a rise of the lance onto the molten iron surface, independent of an operator, to switch the gas quickly and a gas switching method for an immersion type lance for preliminary treatment of molten iron.;SOLUTION: In switching from a state where an immersion lance 11 is immersed in a molten iron 2 and a desiliconization treatment is being carried out by supplying oxygen gas and a fuel gas to a state where the immersion lance 11 is caused to rise onto the molten iron surface and a dephosphorization treatment is carried out by supplying oxygen gas and nitrogen gas, a controller 20 determines whether or not the immersion type lance 11 is present on the molten iron surface on the basis of a detection value of a back pressure detector 17 and, when presence of the immersion type lance 11 on the molten iron surface is determined, give a switching mechanism 16 an order of switching the gas supplied to an outer tube 13 of the immersion type lance 11 from the fuel gas to nitrogen gas.;COPYRIGHT: (C)2015,JPO&INPIT