High-alumina refractory castables have high mechanical strength and good thermal shock and abrasion resistance. The bulk density also does not shrink after drying and calcination at high temperatures. High-alumina castables not only have high strength at room temperature, but also use white cement to bond at medium temperature, and the strength will not change.
Conventional high alumina castables
The construction of high alumina castables is very important, especially the amount of water added. Be sure to control the amount added according to the construction instructions, and do not add more. When stirring, aggregate first, then finely powder, and then add a binder. The stirring time should not be less than 5 minutes.
After the initial setting and final setting of the high-alumina refractory castable after construction, the high-alumina castable should be cured before demoulding. And then after a proper period of natural curing, it can be baked. Then, use it again.
The price of high-aluminum castables is determined according to the bulk density and aluminum content. The price of castables produced from high-aluminum materials with low bulk density will be relatively low. If it is castable with high bulk density and high aluminum content, the price will be relatively high.
The use temperature of high alumina refractory castable is 1300℃. It is mainly used in the lining of various kilns of boilers, blast furnaces, hot blast stoves, and heating furnaces.
High-aluminum and high-strength castables
High-alumina and high-strength castables are a kind of low-concrete castables with a concrete content of less than 8%. Unlike ordinary refractory castables, most of the calcium aluminate concrete in the matrix is replaced by (Elkem) ultrafine powder. In addition, it is a commodity that adds an appropriate amount of preservatives in cooperation with each other to achieve and exceed the characteristics of general concrete castables.
Its key features are as follows:
- The concrete content in the castable is low, that is to say, the calcium oxide content is low. It reduces the low and medium melting of raw materials, thereby improving the refractoriness, high-temperature strength, and slag resistance of the product.
- The mixing water requirement of the castable can only be about one-half of the general castable. Therefore, the compaction of the castable is improved, and the porosity is reduced.
- After forming and maintenance, the converted concrete hydrate is less. There is not a lot of water leakage when heated and roasted. The condition of reducing the medium temperature intensity is only accompanied by a temperature increase. The raw materials are slowly calcined, and the strength is continuously improved.
The use of high-aluminum and high-strength castables. Today’s high-aluminum and high-strength castables are mainly used in industrial kilns in the metallurgical industry, machinery and equipment manufacturing, petrochemical equipment, decorative building materials and other manufacturing industries, and the actual effect is still very good.
Application of high-performance light-weight high-aluminum castables
Performance of high-performance lightweight high-aluminum castables
Optimize the composition and configuration of castables while reducing production costs and meeting the conditions of use of the castables. Formulate a reasonable production process and strengthen process control. Developed and produced a series of high-performance lightweight high-aluminum castables with bulk densities of 1.30 g/cm3, 1.50 g/cm3 and 1.80 g/cm3 to meet the requirements of different parts.
Application of high-performance lightweight high-aluminum castables
The light-weight castable was tested in a 2050 wide and thick plate 3# water-cooled tube in a steel plant, replacing the original heavy-duty high-alumina castable with a bulk density of 2.40 g/cm3. Its long-term operating temperature is about 1300 ℃. The lightweight castable has good fluidity and suitable setting and hardening time. After demoulding, the strength is high, and there is no segregation on the surface of the construction body, which is well received by construction units and users. It has been observed in many inspections that the lightweight material has good thermal shock resistance, the overall surface is smooth, and there is little peeling. The final use is more than 4 years, exceeding the maximum service life of the original heavy castables of 3 years.
The successful use of the lightweight castable in the outer lining of the water-cooled tube of the rolling heating furnace is the first time at home and abroad. The outer lining of the refractory material of the water-cooled tube of the heating furnace can be made lighter, and the energy consumption of the heating furnace can be significantly reduced. After popularization and application, it can create greater economic benefits for steel mills.
Contact us for free samples of the high alumina castable for the industrial furnaces linings in South Africa.
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