| 摘要 |
PURPOSE:To improve air permeability of a sintered raw material and to produce sintered ore having excellent reducibility in the stage of producing the sintered ore for a blast furnace by pelletizing pulverous iron ore and powdery lime with coarse granular iron ore as a nucleus and using the pellets in conjunction with a main raw material. CONSTITUTION:The main raw material 4 for the sintered ore is gurried from each storage tank and is charged into a primary mixer 7 and is mixed. The pulverous iron ore 1 contg. >=70%<=0.125mm. particles, sinter returns 2 of the blast furnace and >=1 or 2 kinds among limestone, quicklime and slaked lime having <=1.50mm. average grain size are pelletized by a disk pelletizer 5. The pulverous iron ore is used in this case at a ratio of >=1.0wt% of the sintered raw material. The limestone powder, etc. are used at >=0.5wt% thereof. The coarse granular ore such as the sintered returns of the blast furnace as the nucleus for pelletization is used at a ratio of 20/80-60/40 with respect to the total weight of the pulverous ore and the limestone. Such pellets 6 are mixed with the main raw material mixture from the mixer 7 in a secondary mixer 8. The sintering raw material having excellent air permeability is thus obtd.
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