A SILICA GLOBE

摘要

The lightweight rigid silica ball having a dense outer coat layer, a porous inner layer and a low absorption rate was prepared by heat-treating a silica gel at 700-1,400 deg.C in a thermal resistant crucible furnace. The silica ball has a diameter less than 20 mm, a thickness of 2-1,000um, an apparent density of 0.05-1.5 g/cm3, a Vickers hardness number of 0.5-11.8 GPa, an actual breaking load of 0.5-50 kg. The ball comprises silica more than 98 %, 0.5 % of alumina, ferric oxide less than 0.25, 1.0 % of Na2O.