| 摘要 |
PROBLEM TO BE SOLVED: To adjust a concentration of total Fe in slag to an optimal range for a dephosphorization reaction and a desiliconization reaction when refining molten pig iron while spraying oxygen gas, without using a solid oxygen source like iron ore. SOLUTION: This refining method includes controlling the concentration of total Fe in the slag into a range of 10 to 40 mass%, when refining the molten pig iron while top-blowing oxygen gas to a bath face of the molten pig iron 2 stored in a refining vessel 5, by adjusting a feeding rate for top-blown oxygen gas, a flow rate of a gas for stirring the molten pig iron, a ratio (L/L<SB>0</SB>) of a depth (L) of a recess formed on the bath face of the molten pig iron when oxygen gas is top blown, to a bath depth (L<SB>0</SB>) of the molten pig iron, and a mass of the slag 15 in the vessel. In this case, it is preferable that the feeding rate of the oxygen gas is 0.5 to 3.0 Nm<SP>3</SP>/min×t, the flow rate of the stirring gas is 0.01 to 0.30 Nm<SP>3</SP>/min×t, the ratio (L/L<SB>0</SB>) is 0.03 to 0.30, and the mass of the slag in the refining vessel is 5 to 50 kg/t when two to four minutes has passed after the supply of oxygen gas had been started. COPYRIGHT: (C)2005,JPO&NCIPI
|
