Brown Fused Alumina, the name is also called Brown Aluminum Oxide , with three kinds of raw materials alumina, carbon material and scrap iron in arc furnace melting reduction and made of brown alumina. The main chemical composition of brown aluminum oxide is AL2O3, its content is 95%-97%, and the others contain a small amount like Fe, Si, Ti, etc.. Brown aluminum oxide is the most basic material, because of its good grinding performance, wide application range and low price, so that it is used widely. According to various dimensions or standards, brown fused alumina can be classified many classifications as follows:
1) According to the chemical composition to distinguish, brown fused alumina can be divided into Grade one, grade two and Lower Grade.
The content of Al2O3 in Grade one is more than 95%. Brown aluminum oxide is made by the high-quality bauxite, a carborundum iron and anthracite mixed according to proportion in arc furnace with high temperature electric melting crystallization. It has high hardness, good toughness, high strength, sharp edges, and high temperature refractory characteristics, so that it can be widely used in grinding wheel manufacturing, production of refractory materials, emery cloth sandpaper, iron and steel smelting, chemical metallurgy, ceramics, glass, cement and other fields.
Brown Fused Alumina lower grade contains alumina (AL2O3) is about 90%. Is was made by the lower grade of the original block of brown aluminum oxide. So it has a lower price. Classification of brown aluminum oxide block is up to the crystallization precipitation resulted in brown fused alumina smelting process, in the middle part of the electric arc furnace is the best crystalline and the impurities is at least, this belongs to Grade one brown aluminum oxide. The upper lower quality is used to make lower grade Brown Aluminum Oxide. Lower grade still has a certain degree of hardness and the characteristics of refractories, with its low cost and it can replace part of a brown aluminum oxide to use. It mainly used for sandblasting, polishing, grinding and cutting, die casting coating, wear non slip, water filtration, refractory material etc.
Brown Fused Alumina second grade is made by the brown aluminum oxide level block of crushing and screening. Its chemical composition is slightly worse, the hardness is slightly lower. But the cost is low, so that it can be used for sandblasting polishing, rust cleaning, grinding cutting, anti slip material, wear-resisting flooring, slippery floors, water treatment and other fields. The alumina (Al2O3) content of the brown aluminum oxide is about 80%, which belongs to second grade.
2) If it is distinguished by bulk density, it can be divided into the Roller, the Barmac and the Ball Mill.
The bulk density of the brown fused alumina with Barmac line is higher than that of the roller and the ball milling. Barmac integer brown aluminum oxide is doing the further processing to brown fused alumina with Barmac equipment, it makes closer to the circular grain type. And increases the bulk density, wear resistance and adhesion of brown fused alumina. The density of the product produced by this brown fused alumina is greater, more closely and the strong grinding ability. For making the refractory material, the product is more compact. For making the grinding wheels, the density is more compact and it improves the grinding ability. For coated abrasives, like sandpaper, sanding belts etc, its adhesion ability is stronger. For sandblasting, it can improves the utilization rate. In the test data, the bulk density of the Barmac corundum is higher than that of the common brown fused alumina.
3) If it is to be distinguished from the smelting furnace, it can be divided into dumping furnace(also called tilting furnace) and fixed furnace. Compared with the fixed furnace, the production of brown fused alumina in tilting furnace is a little better. Its appearance is more apparently in the content of SiO2. The content of SiO2 in the production of brown fused alumina is less than that of the fixed furnace.
4) According to be distinguished by the content of TiO2, then it can be divided into making the resin grinding wheel and the vitrified grinding wheel. The content of TiO2 in brown fused alumina is generally below 3%. The higher the content of TiO2, the grinding wheel will be more blue. Just from the color, it is used to make vitrified grinding wheel will be better. Relatively speaking, for making the resin grinding wheel, the content of TiO2 is not so strict. It mainly depends on customers requirements.
5) If it is in accordance with the cleaning, we have water washed, Acided washed and dry washed.
6) If it is distinguished by doing the processing of brown fused alumina, then it can be divided into calcined, iridium, etc. The calcination is divided into medium temperature calcination and high temperature calcination. Different degrees of calcination, resulting in the performance of brown fused alumina will be different. For example, after the high temperature calcined brown fused alumina, the chemical composition will be more stable. So that the products made by the calcined are more durable.
Finally, in accordance with the purposes to distinguishing, it can be divided into sections of sand, grain size sand(F sand), P sand and micro powder, etc. Different usages, resulting in different models. For example, brown fused alumina section sand is mainly used for refractory materials. Particle size sand(F sand) is mainly used to do the bonded abrasive tools, such as grinding wheel. P sand is used to do the coated abrasives, such as sandpaper, abrasives belts etc.
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