Technological principle of AZS fused brick
[Summary description] AZS fused brick is a product made by melting alumina and other substances in an electric furnace and then cooling and solidifying. It has the advantages of simple process, short process and low product cost. According to the different varieties of AZS fused bricks, different recovery agents can be involved in the torch baking process. When the melting point of corundum is close to 2100, the structure of the alumina melt is similar to that of corundum brick.
AZS fused brick is a product made by melting alumina and other substances in an electric furnace and then cooling and solidifying. It has the advantages of simple process, short process and low product cost. According to the different varieties of AZS fused bricks, different recovery agents can be involved in the torch baking process. When the melting point of corundum is close to 2100, the structure of the alumina melt is similar to that of corundum brick. When the melt cools, the crystal becomes corundum brick. After the corundum brick is melted, the molar volume of the melt increases by 23.5%, the melting heat is 109.2KJ/mol, and the density decreases with the increase of the melt temperature. Then let's understand the process principle of AZS fused brick together!
The so-called "dissolved alumina" generally refers to electrodissolved white corundum. With the name of industrial oxidation or calcined alumina as the material, it is digitized at high temperature in an electric arc furnace. Its Al2O3 content generally exceeds 98.5%, it is white, the crystal is huge, porous, and the porosity is 6335410 -, the main crystal phase a-Al2O3, the crystal strip.
The Al2O3 content of industrial alumina is more than 98.5%, but there are also Na2O, SiO2, and a small amount of Fe2O3. The electrofusion process has a certain purification and purification effect on the preparation of white corundum, but it cannot completely remove these impurities. During this period, Na 2O and Al 2O3 formed in the molten state with a low melting point and a low density, so they segregated in the upper middle of the melt when the melt cooled and crystallized. Although it can be removed by crushing, a small amount remains in the corundum melt, which seriously affects the refractory function of corundum. It is necessary to strictly control the content of Na2O in industrial alumina, and add quartz sand or aluminum fluoride to eliminate or reduce the harmful properties of Na2O. The former uses Al2O3 as nepheline, and the latter promotes the volatilization of Na2O. AZS fused brick
The dense AZS fused brick is made of industrial alumina, which is melted in an electric arc furnace after adding an admixture. The appearance is gray, gray, black or gray-white, Al2O3 is above 98%, the porosity is lower than that of fused white corundum, generally below 4%, and the bulk density is above 3.8g/cm. AZS fused brick is a new type of advanced refractory material, which has the characteristics of acid resistance, alkali resistance, volume stability at high temperature, dense particles, and lower porosity.
Due to inappropriate operation and refining time, Al2O3 may recover excessively when industrial alumina dissolves, forming carbide. Carbide is a harmful impurity in the corundum brick frit. When it encounters water or is stored in humid air, it will undergo hydrolysis to release methane (CH4), which will pulverize the corundum particles; and acid decomposition will occur when it interacts with acid. Therefore, castables and tamping materials made of corundum materials containing carbide will break when grilled.
Fused sub-white corundum is also known as alumina-based fused corundum brick or alumina corundum brick. It is a corundum material that is dissolved by adding a reducing agent, a precipitant and a decarburizing agent to remove impurities such as SiO2, Fe2O3 and TiO2 when the light-burned extra-grade or first-grade alumina loose body material is melted in an electric arc furnace under reducing atmosphere and controlled conditions. Its physical and chemical goals are equivalent to dense fused corundum bricks, with similar colors, Al2O3 content generally above 98.0%, and porosity less than 4%; corundum crystals are generally granular, with a scale of 1-15mm; the main impurity deposits are calcium hexaaluminate (CA6), rutile, aluminum titanate and its solid solution; it is a new type of refractory material second only to fused white corundum bricks and fused dense corundum bricks. The output of AZS fused bricks has increased by nearly 2 times in the past 10 years. In addition to the increased demand for corundum bricks in the petrochemical industry, fertilizer and other industries, long nozzles for continuous casting in the iron and steel industry, integral stoppers for tundish and impregnated aquatic products are also used. Al2O3-C refractories are also used, during which alumina materials are used
AZS fused brick is an advanced refractory material with high refractory degree, corrosion resistance, slag resistance, anti-initialize and high temperature strength. It is widely used in various metallurgical equipment and high temperature furnaces. Various coating materials and tamping materials are also used in fused corundum to improve its function. The production of AZS fused brick products, especially the production of corundum bricks, is more widely used. However, the smelting and production process of AZS fused bricks: smelting - product casting - cooling and annealing - machining. The quality of these processes in production has a great impact, which directly affects the service life of high temperature thermal equipment. Therefore, the production technology requirements of AZS fused bricks and fused corundum bricks will be further developed and improved, and will move towards mechanized production.
The above is the process principle of AZS fused brick. If you need to know more, you can contact us at any time!