Blue Fused Alumina
Blue Fused Alumina makes up about two-thirds of the output, and perhaps one of the widely used abrasives. The electric arc furnace when charged with bauxite and additives we get increased BFA. It is made use of in a wide variety of applications chiefly in bonded abrasives, predominantly grinding wheels for high tensile materials, & coated abrasives like discs, belts, and paper for wood and metalworking.
China is the world's largest producer sharing more than 50% of BFA production. BFA Grains when calcined before use increase hardness, set ceramic coatings that improve the surface roughness and raise the bond of the bonding media with the grain.
White Fused Alumina
White Fused Alumina consequently used in refractories are the purest & highest one in grade. WFA formed as a result of Bayer process alumina is a friable product. As BFA, WFA is also used for manufacturing coated products, grinding wheels (both resin bonded and vitrified). These grains are used also in shot blasting and polishing media; WFA of refractory grade is used as raw material for high alumina refractories
Pink & Red Fused Alumina
Addition of chromium oxide to WFA produces Pink and red fused aluminas, result increase in the toughness of the finished product.
Pink fused alumina has about 2% chromium oxide and has a Knoop hardness of 2,150 when evaluated with that of WFA, which is of 1,950. In order to increase toughness small quantity of titanium oxide is also added to it.
Medium dimension sharp or blocky grains of Pink fused alumina make it apt for precision tool room grinding of hard alloy steels and broad surface.
Red fused alumina has chromium oxide content of about 3% with small amount of calcium oxide ferrous oxide, sodium oxide, silicon oxide, and magnesium oxide. This fused alumina is tougher than pink grades. They too have friable grains, blocky and sharp edged.
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