Manufacturing Process of Brown Fused Alumina(Brown Aluminum Oxide)
Brown Fused Alumina, also called Brown Fused Aluminium Oxide, Brown Aluminum Oxide, or Brown Corundum is a material produced by the fusion process of bauxite(source of aluminum oxide) and other fillings and crushed and screened into grits of different sieving distribution. It is a brown, dense, tough, hard, heat resistant,abrasion-resistant material widely used for abrasives, refractory and sandblasting purposes. The main manufacturing processes as below.
Fusion/Smelting
Calcined Bauxite, Anthracite, and Iron Fillings are the main raw materials for producing Brown Fused Alumina. Shengyu Abrasives choose the best quality calcined bauxite, which contains about 88% aluminum oxide, the main source of Al2O3 in BFA. These raw materials are mixed at a certain proportion and fused/smelted in an electric arc furnace in about 2200℃. Common furnaces are Fixed Furnace or Tilting Furnace(Dumping Furnace). During the fusion process, iron contents settle at the bottom of the furnace, carbon contents go to the furnace’s surface, and aluminum oxide contents in the middle. The raw materials are crystallized, and impurities are reduced. This is the most important process for Brown Fused Alumina, which decided its purity and hardness.
BFA Lumps & Crushing
The fused BFA are cooled down and crushed into big lumps which look brown. This is a material of high aluminum oxide content. BFA lumps are then crushed into smaller sizes for further production.
Screening/Sieving
Brown Fused Alumina lumps grits are then put into crushers for further crushing into smaller sizes and screened into different sieving distribution grits. These are coarse finer grades of good sieving distribution suitable for abrasives and refractory purposes. There are different quality standards such as GB, FEPA, JIS, ANSI standards. After screening, the content of Aluminium Oxide(Al2O3) is about 95%, with little content of Iron Oxide(Fe2O3), Titanium Oxide(TiO2), and Silicon Oxide(SiO2), and little magnetic contents. Magnetic contents are then removed from relevant equipment, which is important as refractory, and abrasives applications’ magnetic contents will harm the finished products. For Al2O3, the finer(smaller) the grit is, the lower the content is.
Washing
Brown Fused Alumina grits are then washed by water or acid to remove dust, magnetic contents, and impurities. These unnecessary contents can easily cause a scratch, corrosion, cracks, and dark spots on abrasives and refractory products. The washing process also helps get harder and purer materials which are better performance and better for recycling.
Packing
After production, Brown Fused Alumina are packed and shipped to customers. The most common packing are Big Bags of 1 metric ton, 1.2 or 1.3 metric tons. Or packed into 25kg woven plastic bags or 25kg paper bags, and 40 bags on a pallet.