| 摘要 |
PURPOSE:To lower the height of an average softening and melt-sticking zone and to blow low Si iron by charging iron-contg. main nut raw materials mainly near the periphery of a furnace to make the layer thickness around the periphery of the furnace thin and operating the furnace with increasing the temp. before tuyeres. CONSTITUTION:The sintered are O1 of ordinary grain sizes is charged to the center-intermediate of the inside of a blast furnace 6 and fine grain sintered ore O2 is charged mainly near the furnace wall by controlling the movable armor or swiveling chute in the top part of said furnace. The layer thickness of the fine grain sintered ore O2 is so controlled as to attain 1/3-2/3 the thickness of the sintered ore O1 layer. When coke C1 is charged next and the above-mentioned charging is repeated, the root position 8 of a softening and melt-sticking zone is heightened. Thereupon, the blast furnace is operated by increasing the temp. before the blast furnace tuyeres 4, lowering the position of the softening and melt-sticking zone of the heightened position 8 and lowering the height of the average softening and melt-sticking zone. Then, the depth of Si in molten iron is lowered. |
