| 摘要 |
PURPOSE:To easily produce a low P and extremely low S molten iron at casting floor by providing a stage executing desiliconization and successive slag-off operation, a stage executing dephosphorization and slag-off operation and desulfurizing stage by stirring the molten iron at dropping into a molten iron ladle, etc., at the time of treating by blowing powdery material and gas into the molten iron in the casting floor trough. CONSTITUTION:At a first stage, the powdery desiliconizing agent is blown by carrier gas through a lance nozzle, set above the molten iron or submerged into the molten iron in the molten iron trough on the casting bed of a blast furnace to mainly execute the desiliconization and at the same time, execute the slag-off operation. Next, at a second stage, the powdery dephosphorizing agent is blown by the carrier gas through the same lance nozzle as the above to mainly execute the dephosphorization and at the same time, execute the slag-off operation. After that, at a third stage, before a tilting trough in the molten iron trough, the powdery the desulfurizing agent is added on the molten iron by natural dropping, and the desulfurization is executed by stirring at the time of dropping from the molten iron trough to the tilting trough and further to a torpedo-car, etc. And, generated desulfurizing slag is transportated to a converter as covering the molten iron surface of the torpedo-car, and after that, the slag-off operation is executed.
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