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• Time of issue:2020-06-29
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(Summary description)　　Practice shows that the blast furnace slag Al2O3 content of more than 16% will have a greater negative impact on the stability of the furnace conditions along the line, and even cause blast disorders. For example, Wuhan No. 7 blast furnace is 3200m3 large, advanced equipment level, after the operation, achieved good operating indicators, but in June 2009, as a result of fluctuations in raw material components, sinter quality deterioration, high Al2O3 content ores, slag iron fluidity, slag and iron can not be discharged, resulting in furnace conditions along the line has become worse, causing disorders furnace conditions, to produce blast caused huge losses. To this end, Wuhan efforts to explore effective measures to solve the problem of blast furnace slag high alumina.
　　
　　According to production experience, in the Al2O3 content of more than 18 percent, rely on high MgO slag to reduce slag viscosity is not feasible, because improving the slag MgO content to rely on improving sinter dolomite flux ratio is achieved when the sinter MgO content increases, the binder phase of fluidity, as it would inevitably lead to increased fuel consumption without reducing the sinter strength. Conclusion The recent laboratory study was sinter MgO content of 2.5% is appropriate, exceed this range, sinter drum index will tend to fall. Therefore, to cope with Al2O3 content is too high due to uncontrolled sources of raw materials, need to study the suitability of the blast furnace slagging system. There are ways to reduce the viscosity of the two, one plus manganese （MnO）;. Second, plus fluorite （CaF2） due to the increase in iron ore will affect the Mn content, it should be added to the fluorite appropriate amount of research methods.
　　Wuhan Iron and Steel blast furnace No. 7 in July 2009 high Al2O3 content in slag-day average of up to 18.6%, the highest reached 22.81%, seriously affecting the separation of iron slag fluidity and iron slag, iron slag discharged directly led to difficulties. Despite many measures, such as adding manganese, hot wash furnaces and other measures, but due to the accumulation of severe hearth furnace conditions did not improve for a long time, and finally decided to wash the oven with fluorite. From July 24, 2009 to July 28, August 3 to 7, add fluorite, fluorite exhausted before using Mn ore. Additional large net during the wash-furnace coke, used to supplement the hearth heat. From the use of point of view, fluorite bonded to the furnace body scrub, treatment effect hearth piled on more significant. After joining the fluorite, significantly reducing the melting point of the slag, slag improved liquidity of iron blast furnace slag obvious, which for recovery furnace conditions played a very important role.
　　
　　It should be noted, though adding slag fluorite help to improve liquidity, but fluorite hearth furnace cooling abdominal wall with severe erosion, so the use of fluorite wash furnace to be very careful. Wuhan Iron and Steel blast furnace in dealing with the 7th July 2009 the hearth accumulation, fluorite is added to the furnace through a uniform charge, fluorite distributed throughout the material surface, a large area of fluorite and bosh, contact cooling system at the hearth, caused a lot of damage to the air, delaying the recovery time after the treatment hearth slag due to high Al2O3 caused accumulation should be improved.
　　Practice shows, CaF2 can reduce high Al2O3 slag viscosity, but CaF2 for the blast furnace refractory damage also played the role, and therefore the use of CaF2 is generally due to the high Al2O3 content in viscosity caused large hearth not live, hearth and accumulation of case use. In the case of Wuhan Iron and Steel slag Al2O3 content of less than 18% of the average daily, CaF2 content of about 2.0% on it. If the normal production time adding CaF2 use, you need to consider the capacity of the blast furnace refractories and other issues.