| 摘要 |
PURPOSE:To suppress the removing rate of carbon and to increase the temp. of a molten iron by adding a carbon source such as coal, coke or the like to the surface of the molten metal in the earliest possible time prior to or after starting of oxygen top blowing. CONSTITUTION:An injection lance 2 for blowing a carrier gas such as gaseous nitrogen and granular flux to the molten metal M charged into a pretreating furnace 1 and a main lance 3 for oxygen top blowing are disposed. A carbon source such as coal, coke or the like is added to the surface of the molten iron in the earliest possible time before the pretreatment of the molten iron M, i.e., before or right after oxygen top blowing and flux blowing. The slag exists hardly on the surface of the molten iron at the timing for said addition and therefore the carbon source reacts preferentially with oxygen. The consumption of the carbon in the molten iron M by oxidation is thus prevented and the temp. of the molten metal M is increased by the reaction heat of combustion of the carbon source. |
