| 摘要 |
PURPOSE:To achieve the improvement of properties of softening and cohesive zone at blast furnace lower part high temperature region, by a method wherein the basicity of slag at the hearth is regulated by injecting SiO2 source from tuyeres of blast furnace and the increase of basicity of lump one charged from the furnace top is made possible. CONSTITUTION:In blast furnace operation wherein by charging agglomerates of high basicity such as sintered one, pellet etc. from furnace top, high basicity slag region is formed at lumpy zone 1, high temperature softening properties being secured, and the softening and cohesive zone 2 and the dripping zone 3 are formed at furnace bottom part high temperature region, the slag basicity controlling region is formed at the hearth 4 by injecting SiO2 source such as silica powder or the like from furnace bottom tuyeres 5. Thereby, the basicity of agglomerates charged from furnace top is raised, the dripping temperature of softening and cohesive zone 2 being elevated, its level being lowered, the contractive rate of filled layer in furnace being improved and further its permeabilily is raised. Therefore, the operation of blast furnace can be stabilized and at the same time the increase of tap amount of iron and the decrease of fuel ratio can be achieved. |
