| 摘要 |
PURPOSE:To execute sintering smelting to iron ore under good thermal efficiency and heat conductive efficiency by charging preheated and prereduced iron ore into a smelting furnace together with carbonic material and slag making material and blowing oxygen at the specific position of tip of an oxygen lance to slag surface level. CONSTITUTION:The iron ore is preheated and prereduced in the preheat- prereduction furnace 30 with exhaust gas from the smelting furnace 10 and charged into the smelting furnace 10 together with the carbonic material and slag making material. Hearupon, inert gas is blown into iron bath 11 and slag layer 12 formed at furnace bottom from the tuyeres 25, 26 and stirred. Together with this, the oxygen is top-blown from the oxygen lance 21, to execute smelting reduction to the iron ore. In the above smelting reduction method, the slag surface level and the tip position of the oxygen lance 21 are measured, and this tip is positioned so as to come to at + or -400mm to the slag surface level. This slag surface level can be measured by using a sub-lance or reflection of the microwave. By this method, by improving the thermal efficiency and heat conductive efficiency to the sintering reduction, the stable operation is executed and damage of refractory at furnace opening part is reduced. |
