| 摘要 |
PROBLEM TO BE SOLVED: To suppress degradation of the desiliconizing reaction efficiency caused by the change in tapping speed by injecting and feeding a desiliconizing agent from an injection lance disposed toward an injection nozzle to a molten iron falling flow formed so that a molten iron is fed from a pig iron runner, allowed it flow down, and poured into a tilted runner with high-speed air flow as a carrying means. SOLUTION: A desiliconizing agent such as iron oxide is charged into a molten iron falling flow 1 which is continuously flowing from a pig iron runner 2 from an injection lance 4 as a desiliconizing agent injection flow 10. In order to direct the desiliconizing agent injection flow 10 toward the molten iron falling flow 1 directly, the injection direction of an injection nozzle of the injection lance 4 is inclined in a range of 30-65 deg. in angle of inclination with respect to the perpendicular direction. The desiliconizing agent which is charged in an accelerated manner in the falling flow 1 with high-speed air flow as a carrying means is accompanied in the falling flow 1, and even when the tapping speed is changed, the desiliconizing agent enters the hot metal 1b deeper together with the flow of the falling flow 1. The desiliconizing agent is started to react when entering the falling flow 1 and stays long as the molten iron flows in an inclined runner 3 to achieve the desiliconizing reaction with the desiliconizing reaction efficiency on the high level.
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