White corundum is one of the commonly used wear-resistant materials in the market. Its main chemical composition is AL2O3. According to the content of alumina, it can be divided into several grades such as special grade and first grade. It is widely used and is mainly used for various materials. Decontamination, anticorrosion, rust removal, polishing, descaling, effect patterns, etc. of workpieces; it has been involved in many industries, especially suitable for various common steels, and can also be used as high-end refractory materials. The advantages of no explosion, no pulverization and no cracking, and it is suitable for many emerging industries and uses;
The requirements for alumina powder in fused white corundum sand smelting mainly focus on the content of alumina and sodium oxide. Because the smelting of white corundum is mainly the process of melting and recrystallization of aluminum oxide powder to form α-Al2O3, if the alumina content in the alumina powder raw material does not reach the specified value, the alumina in the obtained product will inevitably fail to reach the specified value. The expected content, so the alumina content in the alumina powder raw material must be controlled above 98.4%. The sodium oxide in the raw material of alumina powder is the source of sodium peraluminate. One molecule of Na2O will consume eleven molecules of Al2O3 to generate sodium peraluminate (Na2O 11Al2O3), that is, one mass of Na2O will consume 18.1 mass of Al2O3, if the aluminum oxide powder contains 0.6% Na2O It will make 11.46% of corundum blocks become unqualified products, and bring great difficulties to the crushing and selection. Therefore, the smelting of white corundum requires strict control of the Na2O content in the aluminum oxide powder, preferably Na2O<0.3%.
Alumina powder is the main raw material for the manufacture of white corundum and other abrasives. It is white powder, contains Al2O3> 98%, and has a melting point of > 2000 ℃.
White corundum abrasives manufactured in my country all use alumina powder of grade 3 or above, which requires Al2O3 > 98.4%, Na2O ≤ 0.6%, water content as little as possible (H2O ≤ 0.5%), and the particle size is as large as possible.
Alumina powder should prevent other impurities from mixing in the process of transportation and smelting, otherwise it will affect the chemical composition content and color of white corundum, and reduce the quality level of the product. In addition, in order to reduce the flying of the alumina powder during the smelting process and maintain a stable furnace condition, the particle size of the alumina powder is required to be as large as possible and the moisture content as small as possible. It is more suitable to use sand granular alumina powder as the raw material of white corundum sand, which can reduce flying losses, improve working conditions and increase economic benefits.