The difference between super
high alumina brick and ordinary high alumina brick
Special high alumina bricks and ordinary high alumina bricks are different in performance, index and usage. The main reason is the difference in internal quality. Special grade bricks are made of special grade bauxite raw materials. The content of the special grade raw material AL2O3 is more than 85% and the density is 2.8g/cm³. The common raw material AL2O3 is 75% and the density is about 2.6. There is a big difference in the density of the products produced. The refractoriness of ordinary bricks is 1780℃. The refractoriness of the special grade brick is 1820℃, and the firing temperature is about 30℃ higher than that of ordinary bricks. The service life of special grade high alumina bricks is twice that of ordinary high alumina bricks. The crystal phases of high alumina bricks are mainly mullite and glass phases. And the corundum phase composition, the higher the aluminum content, the larger the corundum phase ratio. Therefore, there is a big difference in compressive strength and abrasion resistance.
There is also a difference in load softening temperature between special grade bricks and ordinary bricks. Because the firing temperature differs by about 30°C, the load softening temperature also differs by more than 30°C. Then there is the use temperature. The use temperature of ordinary high alumina bricks is divided into three different grades of high alumina bricks: three grades, two grades, and one grade. ℃.
The high-temperature structural strength, thermal shock stability and slag resistance of the premium bricks are also 1-2 times higher than that of ordinary high-alumina bricks. The slag resistance of ordinary high alumina bricks is not strong, while the special grade bricks have strong slag resistance and are particularly resistant to fatigue at high temperatures. For example, anchor bricks are an example. High aluminum content and good strength are not conducive to use. The aluminum content of anchor bricks is about 55% and has good flexibility. If the aluminum content is too high, the strength is too high, which will make the castable more prone to cracks.
In short, whether it is super high-alumina bricks or ordinary bricks, it is necessary to understand the performance of each grade to meet various temperature and erosion conditions to choose different grades of high-alumina bricks.