High alumina made of bricks for general use is mainly made from super quality bauxite, chamotte binder and additive, when pressed on high pressure switch and cermet under high temperature conditions.
High alumina bricks are widely used in all parts of the lining of a metallurgic furnace, oil, building materials, machinery and armed forces, etc.
https://refractoriesmaterials.com/alumina-bubble-brick/ characteristics and advantages:
1. The dimensions are more accurate.
2. Low iron content and pollution
3. Good temperature stability;
4. High refractoriness,
5. Alkaline / acid erosions,
6. Mechanical and chemical properties in very good.
7. Strong heat shock resistance.
The main products are alumina series, including high-purity corundum brick, mullite corundum brick, corundum furnace tube, alumina hollow ball brick, corundum refractory clay, etc.; zirconia series, including zirconia brick, zirconia hollow sphere brick, Zirconium oxide fiber product, zirconia fiber felt, stabilized fused zirconia sand powder, zirconia ceramic granulated powder, zirconia hollow sphere, industrial zirconia, zirconia ceramic beads, and the like. The company’s products not only involve traditional fields such as steel, petroleum, chemical machinery, and refractory materials, but also extend to emerging industries such as high melting point metal melting, artificial crystals, LEDs, artificial gemstones, and nuclear energy safety.
China has accumulated some experience in the allocation of foaming agents, and there are many types of configuration methods in various places, among which there are several foaming agents.
In order to improve the stability of the mud after the start of the mud, a bone cement with a powder content of 0.3% can be added during the beating. The bone glue must be added after dissolution, otherwise there will still be agglomerates remaining in the mud. The model is usually made of cork or aluminum. The in-mold working surface is required to be smooth and not cracked, and the oil is applied.
In the molding, it is divided into two types according to the pouring place: fire pouring and tunnel drying pouring. Some factories use a frequency of 2,500 times / min, shaking 30-60s pouring, get better results. Industrial alumina, which is not burned or calcined, is added with fine TiO2%. The foam is produced from colloidal rosin, saponin, hydrolyzed resin or the like. The so-called colloidal rosin is prepared from rosin soap (alkaline salt of rosin acid) and water gel (1% to 2%). The foamed mud was poured into the mold, the body of which was dried, and the body to which TiO2 was added was fired at 1550 . The green body without TiO2 was fired at 1,740 .
When the residual moisture of the brick after drying is less than 3%, it can be fired in a kiln. The foam bricks should be placed in the kiln or placed on the upper part of the dense product brick, and the bricks with high density should be installed in the lower part. For some bricks that are in direct contact with the flame, a cover protector should be provided. After firing, the products are cut and ground.
The corundum brick is produced by the foaming method, and volume shrinkage occurs during firing, and the pores in the film are eliminated by sintering, but have no effect on large air holes.