Good or bad way to distinguish quality corundum

Corundum as one of the common resistant material , often involved in the manufacture of wear-resistant products . Especially the production of wear-resistant castable . Castable kind of common ways of its production is to corundum powder and bauxite with a certain proportion of the mixer is made in accordance with certain resistant castable . The material can be used as a variety of high-temperature furnace masonry materials can also be made using prefabricated parts or unfired brick . Corundum in industrial applications , there are many , then how to distinguish corundum and the bad?
Corundum is made ??of carbon , Alumina Oxide , iron three kinds of raw material refining , because the color of iron should be presented so that high-quality brown corundum , corundum observed color is a way to distinguish . Three brown fused alumina is the composition of substances. Three alumina content is directly related to how much good or bad quality corundum . Corundum is divided into three , one of the best is a corundum , followed by two and three , corundum quality standards is mainly to see where AL2O3 content , content of more than 95% of a corundum, that is, we often say that the 95 corundum . Two and three corundum corundum content progressively reduced , the quality decreases. You can see the color purity corundum to distinguish , as corundum containing Fe (iron ) elements , Fe element is reddish-brown , tan it rendered as corundum , you can see by looking at the color to identify the level and quality of corundum .