METHOD FOR IMPROVING RECOVERY OF AFTERBURNING HEAT IN VESSEL PROVIDING LANCE

摘要

PROBLEM TO BE SOLVED: To provide a lance for introducing gaseous oxygen into charged material as an improving method for recovering afterburning heat in a vessel charged with the charging material of molten iron base metal and slag. ;SOLUTION: This method is provided with a process for blowing the oxygen through at least one of first nozzles 14 of the lance for refining molten iron into a steel. The oxygen is blown with effective oxygen flow-rate to generate foaming slag having the quantity to obtain at least 40% of the afterburning heat transfer efficiency without substantially overflowing the slag from the vessel, through at least one position of second nozzles 18 of the lance, from a position above the first nozzles apart with an interval. At this time, the oxygen flow rate from the second nozzles 18 is regulated to the min. at near the starting time of decarburizing peak period to the charged material. Iron oxide- containing pellet can be added to the charging material. In such a case, the oxygen flow rate from the fist nozzles 14 is reduced while charging the iron oxide-containing material and inert gas can be supplemented by the reduced oxygen quantity.;COPYRIGHT: (C)1998,JPO