| 摘要 |
In an integrated steelmaking process the molten pig iron is withdrawn from a blast furnace and conveyed by gravity to a trough like furnace having a plurality of refining zones separated from each other by one or more inverted weirs. In the first refining zone molten iron is prerefined by reaction with high purity oxygen introduced into the iron as it flows by gravity over an inclined base portion of the furnace. In one embodiment the oxygen is introduced into the flowing molten iron from overhead lances in such a manner that the high velocity jets of oxygen oppose the flow of molten iron in the first refining zone and regulate the residence time of the molten iron in the first refining zone. In another embodiment oxygen is introduced into the first refining zone through the furnace inclined base portion in a direction against or opposite to the direction of flow of the molten iron to also regulate the residence time of the molten iron in the first refining zone. Prerefined, deslagged iron flows from the first refining zone to a second zone where additives such as basic slag formers, scrap, mill scale and the like are added. In the second refining zone the refining of the prerefined molten iron is completed by reaction with high purity oxygen passing into the iron to form steel of a desired composition. In one embodiment the steel thus formed in the second refining zone passes therefrom to a ladle for feeding molten steel to a continuous casting machine located in line with the trough like furnace. In another embodiment the steel is introduced into a third refining zone where the composition of the steel is further adjusted by reaction with high purity oxygen introduced into the molten steel and where desired other additives are introduced in pulverulent form. The refining zones have an elongated configuration to provide an enlarged interface between the molten metal and the layer of slag floating thereon to increase the contact time between the molten metal and the slag and increase the removal of phosphorus from the molten metal. The oxygen introduced into the molten iron in the refining zones both controls the flow and regulates the residence time of the molten iron in the respective refining zones and also regulates the slagging of the impurities in the molten iron. In one embodiment carbonaceous liquids are introduced into the furnace around the streams of oxygen to reduce refractory erosion.
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