Refractory brick is a type of ceramic material that has a series of special features that allow you to use it directly in industrial facilities or in domestic gas stoves such as fireplaces. The face of these bricks is flat. This feature gives adhesion with mortar and resists high temperature and abrasion. Due to its good thermal properties, this material is very expensive. Firebrick is currently used for lines of steam boilers, steel boilers, rotary kilns in cement factories. For example, in cases where it has to be bonded with refractory soil and cement is added to improve bond strength. As a result, the mixture will have a muddy appearance. This mixture makes the bond strong enough, and this is one of the characteristics specific to the individual firebrick. Moving these bricks is not as simple as using normal bricks, because due to their identical properties, they react explosively with materials other than suitable materials. Firebrick, like fireclay, in addition to performing the function of fireproofing, is an excellent thermal container, that is, it retains the heat it is exposed to during various applications. 
One of the characteristics of this type of material is that they are produced in different qualities according to the concentration of alumina, and based on this concentration, the brick can withstand higher temperatures or can be used for different environments. Concentrations range from 36 to 99 percent alumina, although silica can also be used. Silicon dioxide is the type of brick used mainly when you want to line steel melting furnaces, in some cases they operate at temperatures above 3000°F (1650°C) when the bricks start to liquefy. To create these bricks, it is necessary to expose their components to low pressure and, in turn, burn them at very high temperatures. Exceptions to this process are bricks that are chemically bonded or those that use bitumen, resin, or rubber for bonding. Types of refractory bricks Firebricks used are of two types depending on the content of clay with silica or alumina. Also due to the content of magnesium and other components. The properties of these compounds allow the brick to withstand high temperatures. Although the behavior of each of them is very specific to the material. 1- Refractory brick with high alumina content The coefficient of thermal expansion of this type of brick is very low. Thanks to this feature, the bricks are prepared to withstand high temperatures, without presenting any kind of deformation or expansion that changes the performance of the brick after cooling. Because the soil needed to make them is very little and because of the high content of alumina, the price of these bricks is high in the market. Also, these bricks can withstand high temperature without any expansion. This is recommended when preparing a barbecue or a fireplace, because we usually put them close together and if they expand too much, the chimney will burst. They support the heating and cooling processes that occur in fireplaces and grills and maintain their characteristics and properties. Temperature tolerance up to 1400 degrees Celsius Aluminum oxide is an electrical insulator but has a relatively high thermal conductivity. Of course, this thermal conductivity changes with temperature. Due to the high melting point of alumina, this material has high resistance and thermal stability. The high hardness of corundum has made this material as a suitable component for abrasive applications and cutting tools. This classification is second after diamond, alumina. 
alumina bricks uses
Aluminum refractory brick It is called a set of refractory bricks that contain 45 to 99 aluminum oxide (Al2O3). According to the percentage of aluminum used in these refractory bricks, we can refer to aluminum bricks. Refractory brick with 85% alumina These bricks contain 85% of aluminum (Al2O3). 85% aluminum brick with mechanical and abrasion resistance and high temperature. The baking temperature of these bricks is about 1200 to 1800 degrees Celsius. This type of brick is used for the safety layer of the electric arc furnace, the roof of the electric arc furnace, the safe area of the cement mountain, the exit area of the cement furnaces, and general applications in places with high abrasion resistance Alma brick, 80% aluminum This type of aluminum firebrick is made of bauxite and various amounts of alumina and clay. The characteristics of this alumina brick are medium porosity, high creep resistance and high strength against high temperature. It is used in the roof of electric arc furnaces and the exit areas of cement furnaces. Aluminum brick 70 This group of aluminum refractory bricks is made of bauxite and various amounts of alumina and clay. The characteristics of this alumina brick are medium porosity, high creep resistance and high strength against high temperature. It is used in the roof of electric arc furnaces and the exit areas of cement furnaces. 
Like the previous bricks, these bricks are designed to be exposed to high temperatures, however, when subjected to alternate or continuous phases from heat to cold, they tend to expand significantly for industrial use, and these continuous changes The temperature as well as the shape affects the brick in such a way that it eventually crumbles. This type of brick is very useful in areas where the temperature is constantly high These types of bricks, which contain more silica, although they withstand high temperatures up to 1700 degrees Celsius, they do not support heating and cooling, and after many expansion and contraction processes, they deteriorate and collapse. . Apart from that, in this type of silica refractory brick, the appearance of cracks and stress is very common. Alma brick is one of the types of refractory bricks. Aluminum brick is a wide variety of refractory bricks that contain 45 to 99 aluminum oxide (Al2O3). This type of refractory brick contains a high percentage of alumina, which is prepared from a mixture of kaolin, bauxite and corundum with a high percentage of aluminum oxide. Aluminum refractory brick is one of the most widely used products for making refractories, refractory materials and making industrial furnaces. Because of the high amount of alumina used in these industrial bricks and the high thermal resistance of aluminum bricks, it can be used in a wide range of industrial furnaces. This brick is made of non-metallic mineral materials, whose constituent elements are Al2O3 and SiO2, so that its Al2O3 content is higher than that of chamotte brick.