1. Spherical grain, low thermal expansion 2. Good anti-breakness, well refractory 3. Low density, neutral materials For supporting ... Advantages:Spherical grain, low thermal expansion, good anti-breakness, well refractory, low density, neutral materials Application:Waterglass bonded sand, ... : 1.1 max, similar to ballPacking density: 1.95-2.05 g/cm3Refractoriness: 1790 C minThermal expansion: 0.13% ...