Synthesis of Spherical β-Quartz Solid-Solution Particles Derived from Cordierite Using a Flame Process

β-Quartz solid-solution has received significant attention as a consequence of its remarkable properties, including a negative thermal expansion coefficient, high mechanical strength, and excellent chemical stability. However, to date, there is no report on the successful production of crystalline spherical β-quartz solid-solution particles. Herein, the crystalline spherical β-quartz solid-solution particles derived from cordierite were successfully fabricated via a flame method followed by a calcination process, representing the first-ever demonstration of this type of synthesis. In-depth investigations of the effect of flame parameters (e.g., adiabatic flame temperature and methane gas flow rate), calcination process conditions (e.g., calcination temperature and calcination time), and the additional amount of anti-sintering agent (e.g., nano-silica) on the particle morphology and crystallinity of β-quartz solid-solution particles were assessed. As a result, the morphology of particles was confirmed to transition from non-spherical to spherical while maintaining a crystalline structure based on optimization of the nano-silica concentration. The nano-silica played an important role in the formation of particles with high crystallinity and good sphericity even at high calcination temperatures. The flame spheroidization process demonstrated herein is a rapid and effective means of fabricating spherical β-quartz solid-solution particles without the use of prefabricated spherical precursors or the addition of template materials, and this efficient method is appropriate for large-scale applications.