Ceramic Foundry sand is made from high quality bauxite, by re-fused and blown to ball type. With advantage of fine surface smooth finish and air permeability, it is a new type casting material for precision casting, coated sand and self hardening sand etc. Main Chemical Composition: Al2O3â?¥75% Fe2O3â?¤5% TiO2 â?¤5% SiO2:5%-20% Physical Properties: Shape:ball, spherical Angularity: 1.1 max, similar to ball Bulk Density:1.95-2.05(g/cm3) Refractoriness: 1790 C min Thermal expansion: 0.13% (10 min at 1000 C )