During the production process of high alumina bricks, the pores of the green body must be controlled. Generally speaking, for bricks weighing less than 15kg, no air holes can be left for exhaust, but for high-alumina bricks weighing more than 15kg, especially those weighing more than 25kg, air holes must be left to allow the gas to be fully discharged. Avoid layering and bubbling of bricks during the firing process.
1. The formed high alumina fire bricks are denser
In order to control the porosity of high alumina bricks, it is also important to use a press forming machine. It is necessary to use a friction press greater than 630 for molding. The alumina silica bricks formed in this way are denser and have lower porosity. If it is an overweight high alumina brick exceeding 50kg or even 100kg, a hydraulic press must be used to form it. It is not easy to use hand molding. Because the manual forming pressure is not enough, it affects the drainage process of the brick body.
Do not leave too many air holes in high alumina refractory bricks weighing more than 25kg. You can check the weight on the surface of the brick and leave 2-6 holes distributed on the surface of the brick to allow the gas inside the high alumina brick to be fully discharged when drying. Otherwise, bubbling, double-layer, or even multi-layer cracking will occur during the firing process. If the rate of delamination or blistering is too high, it will virtually increase production costs.
2. High alumina bricks are installed in the kiln, sintered or placed on the kiln car
When installing, sintering or placing high alumina fire bricks in the kiln car that are too heavy, attention must be paid to, firstly, the provision of fire channels, and secondly, to install them on the upper floor as much as possible, so that the heavy high alumina refractory fire bricks can be fully Sintering ensures that the inside of the heavy brick body is burned through and has better performance.
However, when overweight high alumina bricks are placed on the upper layer for discharge, attention should be paid to the load-bearing capacity of the lower layer of bricks. High-alumina bricks of different qualities cannot be discharged, because the firing temperatures of different qualities are different. If it is lower than the heavy material, the upper layer will be fired. The effect is OK, but the lower high-alumina bricks have been deformed and cannot be used. If the quality of the lower bricks is too high, the lower bricks will not be burned through. When green bricks appear, they have to be refired, which virtually increases the production cycle and cost.
