| 摘要 |
PURPOSE:To obtain a high dephosphorizing and desulfurizing effect with tuyeres of single pipe construction with less oxidation loss of effective elements in molten iron in the stage of blowing dephosphorizing and desulfurizing agents into the molten iron by means of a carrier gas contg. gaseous O2 by specifying the content of Si in the molten iron and the ratio of the flow rate of the gaseous O2/the flow rate in blowing of the dephosphorizing and desulfurizing agents. CONSTITUTION:In blowing dephosphorizing and desulfurizing agents together with a carrier gas contg. gaseous O2 into molten iron contg. Si at <=0.25%, the ratio of the flow rate (l/min) of gaseous O2 in the carrier gas and the flow rate (kg/min) in blowing of the dephosphorizing and desulfurizing agent is set at 5-200l/kg. The dephosphorizing and desulfurizing agents may be either CaO or Na2CO3 base. Here, if the content of Si in the molten iron is in excess of the upper limit, dephosphorization is difficult. If the above-described ratio is below the lower limit, the increase in reaction efficiency is not so high in spite of using O2 in the carrier gas and if in excess of the upper limit, the erosion of a lance for blowing is increased and the blowing is made difficult. |
