... pale, thin-walled hollow, very light weight, bulk density 720kg/m3 (heavy), 418.8kg/m3 (light), particle size of about 0.1 ... of silica and alumina-based, with fine particles, hollow, light weight, high strength, wear resistance, high temperature, heat ... controllable density for buoyancy, improved flow, excellent thermal insulation, light weight, and high strength. Environmentally friendly and 100% they ...