corundum의 유형을 식별하는 방법？

Corundum은 다결정 알루미늄 산화물 물질입니다. 산화 알루미늄은 지구 지각의 주요 구성 요소 중 하나입니다., 풍부한 자원으로, 비교적 저렴하고 얻기 쉽습니다. Corundum has physical and chemical properties such as high temperature resistance, 고강도, high hardness, electrical insulation, 그리고 부식 저항. 그러므로, corundum has become a refractory material with a wide range of uses.

Corundum is a trigonal mineral with NO = 1.768, NE = 1.760, NO-NE = 0.008, a relative density of 4.02, and a hardness of 9. Corundum sometimes contains a small amount of impurities such as Fe, Mn, Cr, and Ti. Corundum can be dyed into different colors by these impurities.

Classification of corundum

Corundum can be divided into two categories according to different manufacturing methods: first, corundum raw materials directly made from bauxite, such as brown corundum and high-aluminum corundum; second, alumina is extracted from bauxite, and then industrial alumina is made into corundum raw materials, such as white corundum, dense corundum, sintered corundum, 등.

In terms of purity and price, white corundum is high, followed by dense corundum, high aluminum corundum is third, and brown corundum is low. White corundum and dense corundum are both produced from industrial alumina. The purity of dense corundum is lower than that of white corundum, but its density is higher than that of white corundum. High aluminum corundum and brown corundum are both produced from bauxite. The purity of brown corundum is lower than that of high-aluminum corundum, but its true density is higher than that of high-aluminum corundum.
Sintered corundum is a refractory raw material made from industrial alumina, which is ground, ball-pressed, and then sintered at a temperature of about 1800°C. Sintered corundum has a high density and a low apparent porosity. Its volume density is >3.50g/Cm3 and its apparent porosity is <4.5%. 그러므로, sintered corundum has properties similar to those of fused corundum: it has good volume stability at high temperature, is not affected by reducing atmosphere, and has a certain resistance to corrosion by molten metal and glass.