High alumina brick can be used at the bottom of the heating furnace, but LZ-75 high alumina refractory bricks must be used. High aluminum bricks with an aluminum content below LZ-75 are not acceptable.
The heating furnace also uses low-cement castables containing aluminum.
LZ-75 high alumina brick is a first-class high-alumina brick in the high alumina series brick . The first-class high alumina refractory brick has a high aluminum content and has better thermal shock stability and slag resistance than the second-class and third-class high aluminum bricks. At present, heating furnaces also use low-cement refractory castables containing 70-75% aluminum. At present, a large proportion of refractory castables are used, because the castables are integrally cast, have good air tightness, and the castable production cycle is short.
Reasons for using castables
Whether using high alumina bricks or castables, each has its own advantages. High-alumina bricks are formed by high-pressure and sintered at high temperatures, and have good thermal shock stability. However, high-alumina bricks need to be constructed with fire mud, and the brick joints are weak areas. The overall castable construction is airtight and there are no brick joints. However, castables have not been treated at high temperatures, and their slag resistance and thermal shock resistance are not as good as high-alumina bricks. The reason why castables are used more now is because of the fast production cycle and good air tightness.
Refractory bricks have a long production cycle
The production cycle of refractory bricks is long because after the raw materials are selected, they need to go through crushing, mixing, molding, molding, sintering, and finished product selection. There are three more processes of molding, sintering, and selection than castables. Under normal circumstances, the production cycle of castables is 2-3 days, and if it is urgently needed, the finished product can be produced on the same day. Refractory high alumina bricks must have a production cycle of 7-10 days. Sometimes, if the sintering task is tight, it may take more than 20 days. So this is another reason why castables are used more frequently.
In short, whether using high alumina bricks or castables, ensuring that the quality meets the needs of use is an important part.
