When talking about the difference between corundum and corundum mullite, let us first talk about corundum and mullite Performance of the two raw materials; the main component of corundum is α-Al2O3, which belongs to the triangular crystal system. The crystals are short columnar, the true density is 3.85~4.01g/cm~3, the hardness is 9, and the melting point is about 2050°C. In addition, corundum itself has high thermal conductivity and insulation, good chemical stability and ability to resist the action of reducing agents.
Therefore, corundum can be used as a raw material for advanced refractory materials. Mullite is rare in nature. Generally speaking, the raw materials used as refractory materials are artificially synthesized. Mullite raw material itself has high purity, high density and good organizational structure. It has the advantages of low creep rate, small thermal expansion, good thermal shock resistance, and strong chemical corrosion resistance, and has been widely used in the refractory industry.
During the construction process of circulating fluidized bed boilers, the main refractory materials used are refractory bricks and castables. pouringWhen used as boiler lining materials, the two most commonly used materials are corundum and corundum mullite. So what are the main differences between corundum and corundum mullite?
I believe that after understanding the above information, you should have a general idea. Adding corundum to refractory castables can increase the aluminum content of the castables to more than 90%, improving the hardness and strength of the castables. However, by adding corundum and mullite to the castable, the aluminum content can reach 99%, the hardness, strength and wear resistance can reach a certain range, and the application effect is also significant.
However, we need to note that when we use them, we often see corundum wear-resistant refractory castables and corundum mullite wear-resistant refractory castables. Even if you buy other types of castables, many manufacturers, such as Mingrui Ceramics Manufacturers, will add more or less corundum or mullite raw materials when producing all wear-resistant and refractory castables to increase the hardness of the castables. and effect construction. As a result, castables can perform more effectively and further save customers money.
Selection of refractory castables
Corundum-mullite refractory castable is actually a castable with better performance than corundum refractory castable. As for what type of castable the boiler uses, the corresponding refractory materials still need to be determined based on the usage of the boiler.
The corundum contained in the preparation of corundum refractory castables is a trigonal crystal system, and the crystal form is generally short columnar. Corundum itself also has high thermal conductivity and electrical insulation properties, excellent chemical stability and the ability to resist the action of reducing agents. Therefore, corundum is an advanced refractory raw material among amorphous refractory materials. Corundum is generally industrial alumina. Or it is made of bauxite after sintering or electric fusion, so the artificial corundum used in industry is artificial corundum. However, the density and hardness of artificial corundum are relatively large, so the use effect is also relatively significant;< br style="margin: 0px; padding: 0px; list-style: none; border: 0px; color: rgb(68, 68, 68); font-family: Microsoft Yahei;" />
The mullite contained in corundum-mullite refractory castables is relatively small in nature. The mullite raw materials used in industry are all artificially synthesized and have high purity, relatively high density, good organizational structure, low creep rate, small thermal expansion, good thermal shock resistance and strong resistance to chemical erosion. It is widely used in the refractory industry and is developing relatively rapidly. However, if we compare corundum and mullite, the hardness and true density of corundum are much better than those of mullite.
The difference between corundum and corundum mullite is mainly in terms of performance. Corundum refractory castables are mainly wear-resistant The fire resistance is relatively good, while the corundum-mullite refractory castable has better thermal shock resistance. The aluminum content of the corundum-mullite castable is not as high as that of the corundum-based high-strength castable. However, the flexibility of corundum mullite castable is relatively good.
