Improving the tensile strength of continuous basalt fiber by mixing basalts

SiO2 is a key factor that affects the tensile strength of continuous basalt fiber, as shown in a previous study. In the present work, to improve the tensile strength of continuous basalt fiber, basalts with a high SiO2 content were mixed with basalts with a low SiO2 content to obtain basalt mixtures with SiO2 contents ranging from 51 to 58 %. The filament tensile strength, melting properties (viscosity, upper-limit crystallization temperature and fiber-forming temperature) of basalt mixtures were investigated. The effects of the chemical composition, mineral components and glass melt homogeneity of basalt mixtures on the tensile strength of basalt fiber were studied, and the tensile strength and melting properties were compared between the basalt mixtures and the individual basalts. The basalt mixtures with high SiO2 contents exhibited higher filament tensile strengths than the individual basalts. However, when the SiO2 content of the basalt mixtures was similar to or less than the SiO2 content of the individual basalts, the filament tensile strength of the basalt mixtures was still higher, which was attributed to the change in the type and content of the mineral components and to the improvement of the glass melt homogeneity as a result of the optimized melting properties.