| 摘要 |
PROBLEM TO BE SOLVED: To execute dephosphorization to a prescribed level in a quick treating time while preventing the development of slopping by adding flux into molten iron incorporated into a top and bottom combined blown converter, optimizing the conditions of oxygen flow rate and stirring power and executing the dephosphorization. SOLUTION: The flux consisting essentially of Al2 O3 -containing material and iron oxide, is added into the molten iron incorporated in the top and bottom combined blown converter type furnace and the stirring gas is bottom-blown while top-blowing the oxygen gas so that the Al2 O3 content contained in sludge at the time of treating becomes 2-16% to execute the dephosphorization of the molten iron. The flow rate of the top-blown oxygen gas is adjusted to 0.7-1.9 Nm<3> /min and the stirring power is adjusted to 1.2-5.0 Kw/t. The stirring power is calculated with the equation. In the equation, Q is the flow rate of the stirring gas (Nm<3> /min), and in case of using CO gas as the stirring gas, this flow rate is converted into two times. Further, T is the molten iron temp. (K), W is the molten iron wt. (t), (h) is blowing depth (m), P is atmospheric pressure (Pa),ρis the molten iron density (kg/cm<3> ) and Tn is stirring gas temp. (K).
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