Synthesis of SiO₂ nanopowders containing quartz and cristobalite phases from silica sands

In this study, extraction and synthesis of SiO₂ nanoparticles from silica sands have been conducted by means of two different methods, i.e. dry method (method 1) and hydrothermal process (method 2). The basic difference between the two methods is in the extraction step. The two methods were compared in terms of being more efficient, economical, and superior in obtaining SiO₂ nanoparticles. The SiO₂ nanoparticles were characterized in terms of phase purity, crystallinity, Si-O functional bonding as well as particles size and morphology. The most interesting fact in this study was the formation of both quartz and cristobalite phases within all prepared SiO₂ nanoparticles.