White aluminum oxide abrasive grain
White aluminum oxide abrasive grain is a common abrasive and refractory material in industrial fields. It is not only used in abrasive production and surface treatment but also used in coating wear-resistant fillers, toughening materials, industrial ceramics, and other fields. White aluminum oxide has high purity, superior hardness, and high grinding efficiency. High-quality abrasive-grade white fused aluminum oxide shall have the following characteristics:
1、 Al2O3 content:
The α- phase aluminum oxide is the main content reflecting high-temperature resistance, wear resistance, and hardness in the material. So the Al2O3 content is the most important indicator of white corundum. Moreover, the Al2O3 content is mainly related to the quality of raw aluminum oxide powder and smelting time.
2、 SiO2 content:
The main secondary content of white aluminum oxide includes Na2O, CaO, SiO2, Fe2O3, etc. The most important one is the content of Na2O. The content of Na2O has a great impact on the quality of white corundum. At present, white aluminum oxide in the market is divided by sodium content. There are several sub-grades with a Sodium content of 0.35%, 0.3%, 0.2%, and 0.1%. Different product applications will have different requirements for sodium content.
Generally, the content of Na2O in white fused aluminum oxide is less than 0.3%. If the content of Na2O is too much, it will be the same as that in the white corundum α- Al2O3 reaction to generate β- Al2O3. At this time β- The content of Al2O3 may be higher than that of Na2O. β- Al2O3 is harmful because it will lead to poor performance on refractoriness and hardness.
Controlling the low sodium content of white corundum will increase the smelting time. As a result, it will increase the smelting production cost. WFA factories can adopt low sodium Al2O3 powder directly for production. But it also increases the cost.
3、 Smelting process:
The main smelting methods of white aluminum oxide include tilting furnace smelting and fixed furnace smelting. The essence of both smelting industries is the process of electric melting and recrystallization of white corundum. Different processes will cause different characteristics. The large white corundum produced by the tilting furnace has a high degree of industrialization and relatively uniform quality. The white aluminum oxide grain produced by the fixed furnace has the characteristics of good central quality and unstable external quality. However, the long-standing cooling time makes the white corundum in the center dense, and the fixed furnace white corundum will be specially used for some special purposes.
4、 Bulk density :
The bulk density of white corundum can reflect the particle volume density, porosity, particle shape, particle size composition, and other indicators to a certain extent. In brief, white alumina with high bulk density has high bulk density, low porosity, and a round particle shape. On the opposite, white aluminum oxide grains with low bulk density has low bulk density, high porosity, sharp particle shape, and concentrated particle size composition.
Generally, users need to select appropriate white aluminum oxide grains according to their own needs to meet different materials for different purposes and functions.
