| 摘要 |
PURPOSE:To produce low Si iron effectively without causing the cooling-down accident of a blast furnace by charging the coke of specific CaO/SiO2 ratio and controlled silica activity into the furnace. CONSTITUTION:Coke of desirable silica activity is formulated by taking it into consideration that the ratio of SiO2 and Al2O3 contained in the ash content the coke is approximately 6.7:3.3, and by controlling its silica activity so as to decrease within a 0.03-0.5 range. To this end, the coke is manufactued by adding materials contg. CaO to raw materials for coke in such a way that the CaO/ SiO2wt% ratio attains 6.0:4.0-2.5:7.5, more specifically, 1.5-0.27 and such coke is used in a blast furnace. Thereby, the production of gaseous SiO in the melt dropping zone formed before the tuyeres is suppressed, and the Si transfer area where the contact chance of this and the metal drops under dropping is reduced is formed, whereby the reduction of Si to the molten iron is suppressed. |
