... , building material,steel-making, environmental,feed and pharmaceutical 1.Specification of Magnesium Oxide Fertilizer grade ITEM RESULTPURITY (MgO) 60.00% - 65.00 %SiO2 ... Materials 23.0 co%2.Main Application:Light magnesium oxide is mainly used for preparation of ceramics, enamel, refractory crucibles , rubber, plastic, wire ...