... . 2.purity 99.7% 3.with ISO9011-2000 certificated calcined raw material,ceramic grade,white powderCalcined alumina for ceramics, refractories and surface ... used in the manufacture of grinding media, glazes, technical and advanced ceramics.Alpha alumina is also used in surface treatment applications ... >=3.93g/cm33mirconalpha-Al2O3 >=94%original size:2-3um calcined raw material,ceramic grade,white powder