... 22M Mullite Sand. 2.It is made in Wellchina Guangdong of CHINA. 3.It is used in precision casting. 1.The ... .6%,TiO2≤0.1%.7.Physical indicatordensity≥2.5g/cm3,specific gravity ---2.6g/cm3,water include< 0.03%,fire resistence≥1750 ... °C,Reduction burning≤0.3-0.4%,Degree of dust ≤0.01-0.03%,PH 7-9,shell-hardness ...