Fabrication and environmental applications of glass microspheres: A review

Continuous technological progress is required to improve production efficiency and environmental quality while maintaining economic competitiveness. A non-negligible contribution to some of these goals can be achieved through the production of glass microspheres for a wide range of applications. The fabrication techniques of glass microspheres including flame synthesis, liquid droplet method, dried gel process and electrical arc process are surveyed. The mechanisms of the recent syntheses of porous and hollow glass microspheres are also reviewed. Glass microspheres are a promising substrate for titania coatings which can be used in water purification and self-cleaning systems. Due to their high mechanical strength and low thermal conductivity, they can also be applied in cementitious and insulating products. Glass microspheres can carry hydrogen gas at pressures of up to 150 MPa. In addition, they can enhance the quality of lead-acid batteries by decreasing the critical volume fraction of the electrodes. Future directions are pointed out on the improvement of the fabrication of 3D glass structures by using glass microspheres as fillers in inks, benefiting from their smooth surface, spherical shape, and high packing density.