... <1.1 4.20-1250mesh refractory foundry sand for casting in mineralCeramic Sand features:1, the thermal expansion coefficient is ... its preparation, no expansion of casting defects.2, sand for the ball, good fluidity, easy and good ventilation3, ... materials, neutral sand, acid, alkali binder apply 5, re-use regeneration performance, cost-effective6, high refractoriness, easy collapsibility7, thermal ...