... years professional manufacture 2.ISO9001:2008 3.size:3,6,10,13,19,25,38,50mm 3,6,10,13,19,25,38,50mm Ceramic ballis one ... (g/cm3) 1.35-1.4Specific gravity (g/cm3)2.3-2.4Free volume (%)40Operation temp.(max) (°C)1100Moh’s hardness ... (scale)>6.5Acid resistance (%)>99.6Alkali resistance (%)>85 Size available & Crush strength ...