Item ZZ-1 ZZ-2 ZZ-3 Al2O3(%min) 98 85 77 SiO2(%max) 0.15 - 0.5 MgO(%max) 1.0 1.5 - Na2O(%max) 0.2 0.5 0.5 B.D (g/cm3) 2.98 2.96 2.86 C.C.S 100 90 80 Application: used in crucible, hearth, nozzle pocket tundish