Influences of alkaline-earth metal oxides on the properties of vitrified bond

Alkaline-earth metal oxides (MgO, CaO, SrO and BaO) were introduced to Na2O-B2O3-Al2O3-SiO2 vitrified bond, and their effects on the properties of the vitrified bond were investigated through the measurements of refractoriness, fluidity and bending strength. The results showed the refractoriness of the vitrified bond was reduced and the fluidity of the bond increased with the addition of alkaline earth metal oxides in the order of CaO>SrO>BaO>MgO. When 2-10wt% MgO, CaO and BaO was added into the bond respectively, the vitrified bond was relatively dense due to high viscosity, and the strength was all improved to some extent. However, when more than 4wt% SrO was added, the strength decreased sharply because of the deterioration of microstructure. It was concluded that the bending strength of the bond was affected by alkaline-earth metal oxides in the order of CaO>MgO>BaO>SrO.