METHOD FOR DECARBURIZATION REFINING OF MOLTEN PIG IRON IN CONVERTER

摘要

PROBLEM TO BE SOLVED: To stabilize to a low level, the phosphorus concentration in a molten pig iron at completion of decarburization refining without supplying excess oxygen when decarburization-refining a molten pig iron in a converter by charging a part of lime source from a top-blowing lance.;SOLUTION: When decarburization-refining the molten pig iron 16 in the converter by feeding gaseous oxygen and charging the lime source 19 from the top-blowing lance 2 while blowing an agitating gas from a bottom-blowing tuyere 3, the FeO generation amount in a furnace is estimated on the basis of an unclear oxygen amount obtained by calculating an oxygen balance from an oxygen gas flow from the top-blowing lance, exhaust composition, exhaust flow, auxiliary material charge amount and a molten pig iron component. By checking the transition of the estimated FeO generation amount, at least one of the oxygen gas flow from the top-blowing lance, height of the top-blowing lance and the agitating gas flow is controlled, and by such a control, the FeO generation amount in the furnace is controlled in the range of 3-30 kg/molten iron-t(sec) from refining start up to the time point of feeding the oxygen amount of 40 vol.% of total oxygen amount.;COPYRIGHT: (C)2012,JPO&INPIT