What material is white corundum?

What material is white corundum?
White corundum is an alumina material.
White corundum is made of high-quality alumina powder by high temperature smelting.
The main chemical composition of white corundum: AL2O3
White corundum section sand alumina content: more than 99.5%
White corundum fine powder alumina content: more than 99%
Alumina content of white corundum grain size sand: more than 99.5%
Alumina content of white corundum powder: more than 99%