| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for producing molten pig iron, which can melt a ferruginous cold charge which is partially or entirely composed of reduced iron containing unreduced iron oxides while adequately keeping unit consumptions of a carbonaceous material and oxygen, and to provide a condition of forming the optimal molten slag for melting the ferruginous cold charge with high productivity. SOLUTION: This method for producing the molten pig iron by supplying the reduced iron, the carbonaceous material and oxygen to a melting furnace containing seed molten iron includes controlling an index Rsm to 0.6 to 0.85, which is determined by a relationship between the depth of a molten pig iron bath containing only the seed molten iron before the melting operation starts and the depth of the molten iron bath after the melting operation has been completed, expressed by depth of molten iron bath before melting operation/depth of molten pig iron bath after completion of melting operation. The method also includes controlling the quantity of slag existing in the melting furnace so that an index Rss can be in between 0.1 and 0.5, which is determined by a relationship between the quantity of remaining slag before the melting operation starts and the quantity of the slag after the melting operation has been finished, expressed by quantity of remaining slag before melting operation starts/quantity of slag after melting operation has been finished. COPYRIGHT: (C)2007,JPO&INPIT
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