White electrofused alumina

White electrofused alumina(white electrofused aluminum oxide) is the mainstream abrasive for abrasive tools and blasting media. White fused alumina has good self-sharpening and strong cutting ability and can be used for grinding various alloys, metals, stainless steel, and non-metallic materials. However, the quality of WFA varies always. Here we are going to explain several principles to get goods quality.

Pay attention to the chemical composition of the White electrofused alumina.  The chemical composition is an important indicator of the quality of WFA. The grade of White electrofused alumina is also divided according to Al2O3 content. On the one hand, the Al2O3 content of A-grade white fused alumina is not less than 98.5%. The white fused alumina from good white fused alumina manufacturers has a higher purity of 99.2%, 99.5%, and 99.8%. On the other hand, the content of sodium oxide in the chemical composition should be as low as possible. Na2O prevents the formation of the alpha crystal phase during the production of White electrofused alumina, while the conversion of alpha alumina to aluminum affects the hardness of WFA. In the national standard, the content of first-grade white corundum sodium oxide is less than 0.4%. For white corundum produced by excellent white corundum manufacturers, the sodium oxide content is not more than 0.3% / 0.2%.

pay attention to the raw materials of Na2O. The raw material of white corundum is industrial alumina powder. Just like quality differences exist in all industries, there are subtle differences in the quality of alumina powder. This difference is mainly reflected in the sodium content. The alumina powder with high aluminum and low sodium is expensive, and the quality of the white corundum produced is also better.

• For WFA grain. Some manufacturers adopt recycleed white corundum from sandblasting as raw material. They wash and resieve the reclaimed WFA. Thus, the price is low. But the particle shape and particle size of the product cannot be controlled.
• For WFA fine powder. The powder made from A-grade WFA blocks is a good raw material for refractory castables and refractory coatings.  Reclaimed WFA powder from the sand-making pipeline gets lower quality.
• For White electrofused alumina polishing powder, the powder products produced by dust extraction powder, fine powder, and fine sand have uneven particle size distribution and are prone to fine dust and coarse particles.

Pay attention to the production process of White electrofused alumina. The smelting process of white corundum is divided into a frit method and dumping method.  And the corresponding melting equipment is fixing furnace and tilting furnace. The white corundum produced by the fixing furnace has better toughness and hardness than that of the tilting furnace.

• For White fused alumina grain. The sand-making process has a direct impact on the grain shape, magnetic content and bulk density of white corundum. The WFA produced by ceramic ball milling and Barmac milling machines has low magnetic content, less iron residue and high bulk density.  Vitrified abrasive and bonded abrasive manufacturers always have different rules on the bulk density.
• For WFA section sand. The WFA particles produced by the Barmac sand-making machine are more round.  It is conducive to the pouring of refractory materials.
• For White electrofused alumina powder.  The WFA washed with overflow and classified has good powder fluidity, fewer impurities, and a narrow particle range. Suitable for grinding, ceramic products, coating fillers, etc.

Finally, users should also pay attention to the price of white electrofused alumina. Products with lower prices than normal levels often have the risk of doping with other materials such as silica sand. We hope this article can help you purchase white corundum abrasives reasonably.