4-Size Powder Al2O3 99% min 98.5% min Na2O 0.4% max 0.4 % SiO2 0.2% max 0.25% max Fe2O3 0.15% max 0.5% max Hardness(Mohs) 9.0 min True density 3.95 g/cc min Principal crystalline Phase α-Al2O3 index White Alumina White Alumina with a little Sodium Al2O3 >99% >99.3% SiO2 <0.15% <0.15% Fe2O3 <0.1% <0.1% Na2O <0.3% <0.25% Volume density ≥3.50g/cm3 ≥3.55g/cm3 Real density α-Al2O3 Main crystallographic direction 8-5MM 5-3MM 3-1MM 1-10MM Coarseness 16# 20# 22# 24# 36# 40# 80# 90# 120# Fines 180F 200F 240F 325F Physical Properties Chemical Composition(%) Particle Size Fine Powder Principal crystal phase;α-Al2O3 Al2O3 ≥99 ≥98.5 Cystal system: Hexzagon Na2O ≤0.4 ≤0.4 Colour and lustre: White SiO2 ≤0.2 ≤0.25 True densyty(g/cm3):≥3.95 Fe2O3 ≤0.15 ≤0.5 Packing density(g/cm3):1.75-1.95 Mohs hardness:9 Linear expansion Coefficent (1/°C):8.3?10-4 Grain size(mm) 3~5, 1~3, 0~1 Fine Powder(mesh) 80,120,240,320 etc Micro Powder(um) 3~5,5~10 Typical Min Max Al2O3 98.21 98.00 - Fe2O3 0.10 - 0.20 Na2O 0.01 - 0.05 SiO2 0.31 - 0.50 TiO2 1.05 - 1.20 Magnetism 0.03 - 0.05 Water 0.05 - 0.20 B.D.g/cm3 3.95 3.90 - Mesh sizes -1mm,1-3mm.3-5mm,-60mesh(250um),3?6mesh,6?4mesh,14?70mesh,4?10mesh,-4mesh,-14mesh,-70mesh,-100mesh,-200mesh,-325mesh. Chemical composition(%) Grain Size Range Al2O3 Na2O Fe2O3 Min Typical Max Typical Max Typical 12#-90# 98.50 99.50 0.40 0.35 0.05 0.04 100#-240# 98.50 99.50 0.40 0.38 0.05 0.04 240#-0 98.00 99.00 0.50 0.45 0.05 0.04 320#-0 97.50 99.00 0.50 0.45 0.05 0.04 1-0 8-0 98.50 99.50 0.40 0.36 0.06 0.05