There are several cases of cracks in Silica Refractory Brick: if it is a layer crack or a vertical crack in the brick, it is caused by the press hammer without exhaust during the molding and pressing of the brick. If it is horizontal or mesh cracks, it is caused by the temperature rising too fast during the drying process. In another case, improper control of the firing temperature will also produce horizontal cracks on the surface of the silicon brick.
Cracks should be said to be an important part of the yield of silica bricks. If not properly controlled, the cost will increase significantly.
Silica Refractory Brick compared with high aluminum brick
Silica brick is an acidic product, compared with the high aluminum brick of neutral products, the yield is low, and another important reason is that the expansion coefficient of silicon brick is high, if the mold is not correct, it will cause the finished size of silica refractory brick to seriously exceed the standard.
During the firing process of silica brick, the crystal changes, the volume expansion coefficient is large, and it is extremely easy to crack. However, if it is a micro crack, the structural elasticity can be improved.
Crack description of Silica Refractory Brick
The cracks of silicon brick are divided into surface cracks and internal cracks. Among them, that is, machine pressure cracks and temperature firing cracks, if the surface cracks criss-cross, the length is different. It is not thoroughly dry, the moisture of the product is not discharged, and it begins to be produced by high temperature sintering, and the kiln for burning silicon bricks should be at least 150 meters above, otherwise, the temperature insulation performance is not good, and the crack ratio of fired silica bricks will be very high.
Spalling appears in the process of product molding, mold aging or pressed brick without exhaust, will appear spalling, spalling silicon refractory brick is not usable, the internal quality is not good, simply can not be used at high temperatures. This crack is a mechanical crack.
If it is a network crack, it is caused by large temperature fluctuations, and the product is inherently uneven, another possibility is that the aggregate and powder are stirred unevenly during the mixing process, and there will be a network crack.
The transverse crack of the silicon refractory brick appears on the outside of the kiln car brick stack during the firing process, especially the top product. The high temperature, coupled with the kiln car loading track is not reserved reasonably, and the flame is sprayed directly on the brick surface under uneven heat.
The crack of Silica Refractory Brick is also related to the process
The crack of silicon refractory brick is also related to the process, if there are too many fine particles, there will be cracks, the poor quality of the binder added in the matching process will also appear cracks, the drying does not discharge water or the kiln car is not scientific, and the burning heating is too fast, which is the bad situation of cracking.
If you want to control the crack of Silica Refractory Brick, it is necessary to seriously control the production process from the ratio of raw materials to the molding and firing process, and every link should be paid attention to, the technical level of the production personnel is formed to a certain level, and then the temperature of the fired brick is controlled when burning, then the crack phenomenon will be solved.
