Appearance White Crystalline Powder Total Al2O3 Content 96%min Total SiO2 Content 0.18%max Loss on Ignition 1%max Alumina ( Al2O3 ) 2%max Sulfates ( as SO4 ) 0.002%max Phosphates ( as P2O5 ) 0.008%max Iron ( as Fe2O3) 0.02%max Sieve Analysis 10% max (100 mesh), 90% min (325 mesh)