| 摘要 |
<P>PROBLEM TO BE SOLVED: To stabilize phosphorous concentration in molten iron in lower level after completion of decarburizing and refining without excessively supplying oxygen gas when decarburizing and refining the molten iron in a converter. <P>SOLUTION: In decarburizing and refining the molten iron 16 in the converter while feeding oxygen gas from the top blowing lance 2 and blowing in agitation gas from the bottom-blowing tuyere 3, the FeO concentration of slag 17 in the converter is estimated based on the unknown oxygen quantity obtained by sequentially calculating the oxygen balance from an oxygen gas flowing quantity from a top blowing lance, the composition of exhausted gas during refining, a flowing quantity of the exhausted gas, a sub raw material charging quantity, and the component of the molten iron, at least one kind of the oxygen gas flowing quantity from the top blowing lance, the lance height of the top blowing lance, and the flowing quantity of the agitation gas from the bottom blowing tuyere is controlled according to the transition of the estimated FeO concentration, the FeO concentration in the slag in the converter is adjusted within the range 5 to 30 mass% till the time when supplying the oxygen quantity of 40 vol.% of the whole oxygen quantity from the time when starting refining by the control. <P>COPYRIGHT: (C)2012,JPO&INPIT |
