Views: 23 Author: SEPPE Publish Time: 2017-07-01 Origin: SEPPE
produced by fusion process of bauxite(source of aluminium 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. Main manufacturing processes as below.
Calcined Bauxite, Anthracite and Iron Fillings are the main raw materials for producing of Brown Fused Alumina. Shengyu Abrasives choose the best quality calcined bauxite which contains about 88% aluminium oxide, which is the main source of Al2O3 in BFA. These raw materials are mixed together at certain proportion and fused/smelted in electric arc furnace in about 2200℃. Common furnaces are Fixed Furnace or Tilting Furnace(Dumping Furnace). During fusion process, iron contents settle at the bottom of the furnace, carbon contents go to surface of furnace, and aluminium 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 purity and hardness of it.
The fused BFA are cooled down and crushed into big lumps which look brown. This is material of high aluminium oxide content. BFA lumps are then crushed into smaller sizes for further production.
Brown Fused Alumina lumps grits are then put into crushers for further crushing into smaller sizes and screened into grits of different sieving distribution. This is coarse finer grades of good sieving distribution suitable for abrasives and refractory purposes. There are different quality standard such as GB,FEPA,JIS,ANSI standards. After screening, 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 relevant equipment, which process is important as for refractory and abrasives applications magnetic contents will harm the finished products. For Al2O3, the finer(smaller) the grit is, the lower the content is.
Brown Fused Alumina grits are then washed by water or acid to remove dust, magnetic contents and impurities. These unnecessary contents are easy to cause scratch, corrosion, cracks and dark spots on abrasives and refractory products. Washing process also helps get harder and purer materials which have better performance and better for recycling.