... 2,light silicon treatment 3,purity96%,mesh40-325 High temperature magnesium oxide powder for heating elements1, 900C-1100C2, NAMEGRADE CHEMICAL COMPOSTION PHYSICAL PROPERTIESMgOCaOFe2O3SiO2Al2O3MESH ... ,immediate sealing after cooling. (Working temperature:1000-1100) High temperature magnesium oxide powder for heating elements