Longevity of blast furnace is the main development trend of blast furnace smelting technology. Extending blast furnace life can effectively improve production efficiency, greatly reduce overhaul investment, and reduce production loss during overhaul. It is an important guarantee for high efficiency and low consumption of blast furnace, and has become a modern blast furnace technology. The main sign of progress. The blast furnace hearth and the bottom of the furnace are the worst working areas of the blast furnace. Its life is the key factor determining the life of the blast furnace. So far, the service life of the hearth and the bottom of the furnace is still a sign of the life of the blast furnace. In this article, the factors affecting the longevity of the blast furnace are described.

Quality of waterless cannon

The gun mud should have good comprehensive performance, and must meet moderate plasticity, suitable curing temperature and speed, fast sinterability, good volume stability, good opening, and strong anti-slag iron melt. Erosion and scouring. If the quality of the mud is unqualified, it may cause problems such as difficulty in mud drilling, difficulty in seeping iron, difficulty in opening iron, iron mouth, broken iron mouth, etc., which deteriorates the working condition of the iron mouth and affects the normal production of the blast furnace, which is not conducive to the hearth. Longevity of the bottom of the furnace.

Plasticity of the cannon

Plasticity is the primary key factor in determining the performance of the mud. Gaussian values are often used to characterize the plasticity index. However, due to the different types of materials and particle grading of the mud, especially the type and amount of binder, and the differences in the process equipment of the blast furnaces, there is no uniform standard for the appropriate Marsh values of different guns. Appropriate plasticity must be met: it has good mud-driving performance, and it can form a relatively dense mud pack after being punched in. If the plasticity is lacking, there may be more than the mud pressure of the equipment, the muddy amount is small, the formed mud pack is small, the shallow iron mouth appears, or the mud pack is not dense, and it is easy to seep. Once there is severe iron infiltration, it can only be opened by oxygen burning or even smashing, but it is easy to destroy the 孑L road and mud pack, speed up the iron output, shorten the iron discharge time, and can not achieve good furnace discharge. Therefore, it has an adverse effect on the smelting process such as the working state of the hearth, the quality of the molten iron and the furnace condition. Excessive plasticity, it is also difficult to form an ideal mud pack, and the sludge solidification and sintering is slow, the gas enthalpy L rate is high after burning, and it is not resistant to erosion and erosion. If the complete mud pack cannot be formed for a long time, the inner lining brick of the iron mouth will be accelerated and damaged, and the safety of the cooling wall will be endangered in a serious case, and even the burning accident of the hearth may occur.

Suitable curing temperature and speed

If the curing temperature of the mud is too low and the curing speed is too fast, it will easily dry out in the cannon of the mud cannon and lose plasticity, which will make it difficult to muddy, or the movable performance will be attenuated too quickly during the mud process. Mud packs are not good. If the curing temperature is too high and the speed is too slow, the mud pack will solidify and sinter after blocking, especially in the vicinity of the furnace door, it may be difficult to solidify, resulting in too low strength at the opening, and rapid reaming due to poor sintering at the initial stage of tapping. . The expansion of the iron mouth at the beginning will increase the flow rate of the slag iron, the circulation of molten iron in the hearth and the bottom of the furnace will increase significantly, and the viscous shear stress will also increase, accelerating the erosion rate of the wall and bottom of the hearth. Moreover, controlling the appropriate rate of tapping can significantly reduce the amount of slag retained, which is one of the conditions for achieving good hearth emissions.

Rapid sinterability

The waterless cannon contains a large amount of coke powder, carbide, etc., which are poorly sintered. The organic binder "wrapps" a small particle of the material, so that the sinter of the cannon itself is not ideal, and the low and medium temperature strength is mainly caused by A binder is provided. On the other hand, the presence of more water and low volatility in the mud mud requires the rapid sintering performance of the gun mud. Otherwise, due to the solidification and sintering of the mud, the mud mud phenomenon occurs, especially for single field tapping. Gun mud, because the iron separation interval is very short, some less than half an hour, the early stage of tapping is easy to emit black smoke, violent splashing, and even rocket, not only worsening the operating environment, the gun mud is difficult to resist slag iron due to poor sintering The effect is very unfavorable for the longevity of the hearth and the bottom of the furnace.

Volume stability

Because the gun mud has good plasticity, it is difficult to form a dense mud pack. It can be said that the plasticity and compactness are a pair of contradictions; the proportion of the mud powder is large, and the loss of the organic binder at the high temperature is also large. These all determine that the mud is easy to shrink greatly during the sintering process, so it is necessary to add a swelling agent to ensure the volume stability of the mud after burning, otherwise it is easy to use between the new and old gun mud or the mud and the furnace wall during use. The combination between the two is not good, and there is a phenomenon of broken iron joints. Especially the broken iron joint formed by the crack between the mud pack and the furnace wall is the most unfavorable for the longevity of the hearth and the bottom of the furnace.

Anti-erosion and scouring

On the one hand, the blast furnace continues to strengthen smelting. On the other hand, due to the depletion of high-quality resources and the rapid increase in prices, the grade of raw materials for human furnaces continues to decline, resulting in a significant increase in the amount of slag iron, especially slag, which is particularly resistant to erosion of the mud. Higher and higher. This is the general status of domestic blast furnaces. In addition, the process parameters of different blast furnace smelting are often very different, such as blast furnace effective volume, utilization coefficient, slag alkalinity, iron system, etc., so it has strong selectivity to the mud, and must be specific to the blast furnace Use requires targeted manure formulation adjustments. If the anti-slag iron capacity of the gun mud is not enough and the reaming is too fast, it will increase the scouring wear of the slag iron on the bottom of the hearth, and the slag iron will not be produced, which will affect the furnace condition.