... Ultimate Crystal Size: 2-4um use for ceramics,refractory,polishing Product DescriptionCalcined Alumina Appearance: White powder Material ... It used as high quality material for aluminous refractory, sintering coroundum and ceramics. Application: It's ... wear-resisting, corrosion-resisting products, such as high alumina refractory products, strong ceramics, high grade abrasive, electromagnetic equipments ...