For a long time, the lining of the blast furnace bottom and hearth has mainly been made of various types of carbon bricks and ceramic cup materials, and their quality and performance have been continuously improved to achieve the requirements of extending the life of the blast furnace. However, high-intensity smelting and the continuous decline in the grade of raw materials entering the furnace have led to a large amount of enrichment of impurities such as alkali metals and zinc in the blast furnace, and the furnace environment has become increasingly harsh, posing a more severe challenge to the lining materials at the bottom of the furnace hearth. Rongsheng Kiln Refractory Lining Material Manufacturer can customize the design and maintenance solutions of refractory lining according to the actual working conditions of industrial furnaces. Customization of blast furnace carbon bricks. Contact Rongsheng for more information.
Working Conditions of Blast Furnace Lining Materials
To adapt to the increasingly complex furnace environment, the lining materials used must have good thermal conductivity, excellent resistance to molten iron corrosion, excellent alkali resistance, excellent slag resistance, good zinc corrosion resistance, and good oxidation resistance.
However, carbon bricks and ceramic cup materials have different degrees of performance shortcomings. For example, carbon bricks have excellent thermal conductivity, slag resistance, alkali resistance, and other properties, but poor resistance to molten iron corrosion. The “rat hole” burn-through in some blast furnaces is caused by the direct contact of carbon bricks with molten iron after the carbon bricks lose the isolation protection of the viscous layer in some parts. At the same time, the carbon bricks under the tuyere sleeve will be oxidized due to water leakage, and its oxidation resistance is its fatal weakness. Therefore, although the use of carbon bricks in the furnace can play the role of the cooling system, it still has serious deficiencies and safety hazards. Although ceramic materials have excellent resistance to molten iron corrosion, alkali resistance, and good oxidation resistance, their low thermal conductivity limits the role of the cooling system. They can no longer keep up with the demand for the safety and longevity of large-scale and efficient blast furnaces. Therefore, a new material with excellent comprehensive performance that can improve the safety and longevity of the lower part of the blast furnace is urgently needed.
Finally, carbon was introduced into the microporous corundum ceramic cup for testing, and a new type of carbon composite brick was obtained, which combines the advantages of excellent carbon bricks and ceramic cup materials. Its main performance indicators have obvious advantages over high-quality carbon bricks and ceramic cups at home and abroad.
Performance Advantages of Carbon Composite Bricks for Blast Furnaces
Carbon composite bricks combine the advantages of carbon bricks and ceramic cup materials well while overcoming their respective shortcomings. In particular, they solve the problem of poor iron dissolution resistance, oxidation resistance, and zinc corrosion resistance of carbon bricks. And meet the basic performance requirements of the lining materials in the furnace area. At the same time, its thermal conductivity decreases from low temperature to high temperature, which is more in line with the design principles of furnace bottom furnace lining than carbon brick materials. It is fully capable of becoming a replacement product for the lining of the furnace bottom furnace.
In order to better play the performance advantages of carbon composite bricks, the research team also targeted the problems existing in the design of traditional furnace bottom furnace structure. Combined with the performance of carbon composite bricks, a new design scheme was proposed. That is, carbon composite bricks are used in all furnace parts, carbon composite bricks are used in the upper part of the furnace bottom, and high thermal conductivity carbon bricks are used in the lower part.
Through this technical solution, the following problems were successfully solved:
1) The thermal conductivity of the furnace bottom hearth lining tends to decrease from the cold side to the hot side. This trend meets the needs of the cooling system design and the design principles of the furnace bottom hearth lining of the blast furnace.
2) Carbon composite bricks are used as the hearth material. Because they contain a certain amount of carbon, their thermal expansion coefficient is much lower than that of ceramic cup materials. It can avoid the phenomenon of tuyere warping and furnace shell cracking.
3) Because carbon composite bricks have good thermal conductivity and both ceramic and carbon bonding. Therefore, it is very easy to form a slag iron shell protective layer on the working surface. Slag iron shell protection is an important condition for forming a permanent furnace bottom hearth structure. Even if the protection of the protective layer is temporarily lost under abnormal conditions, the excellent iron corrosion resistance of carbon composite bricks can also buy time for the formation of the protective layer again.
4) The application of carbon composite bricks at the furnace bottom completely controls the 1150℃ isotherm and the 800℃ isotherm within the carbon composite brick layer. Even if the furnace bottom is corroded in the future, the carbon bricks will not be corroded. That is to say, the carbon bricks do not contact the molten iron during the entire furnace service, thus avoiding the problem of poor resistance of carbon bricks to iron corrosion.
Rongsheng Carbon Brick Sales
Carbon composite bricks solve the problem of poor iron dissolution resistance, oxidation resistance, and zinc corrosion resistance of carbon bricks. It has a good self-protection furnace mechanism and can form a stable protective layer system. Under the harsh conditions of low-grade furnace charge, high-intensity smelting, and frequent replacement of raw fuel types, ensure that the temperature gradient distribution of the furnace bottom and hearth is reasonable and the heat flow intensity is appropriate so that the cooling system can fully play its role. Thereby ensuring the safety of the furnace bottom and hearth, and realizing safe operation, efficient production, and healthy and long life of the blast furnace. Rongsheng kiln refractory material manufacturer can provide high-quality carbon brick refractory lining materials for blast furnaces. Rongsheng carbon brick sales, high-performance carbon composite bricks. Effectively solve the three major problems of unstable production, high smelting intensity, and low grade of ore entering the furnace in blast furnace production. The emergence and application of carbon composite brick lining materials and structures have taken the longevity of blast furnaces to a new level and effectively extended the service life of the furnace. Contact Rongsheng for a free quote.
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