Development of tridymite structure studied through crystal growth by X-ray diffraction: Influence of synthesis parameters

Abstract

The synthesis progression of the crystalline silica polymorph tridymite has been investigated through the crystallization evolution using X-ray diffraction (XRD) technique. The impact of various synthesis variables on the crystallization of tridymite was examined, including the crystallinity of the raw material, the type and concentration of the mineralizer used, as well as the effect of the maximum furnace temperature and soaking time. The evolution of the crystal structure was analyzed using X-ray diffraction, and the best-synthesized final product was characterized by X-ray fluorescence, scanning electron microscopy and specific surface area. Due to the inherently sluggish nature of the tridymite transition, it was not possible to synthesize tridymite without the presence of an alkali in the composition. While all the variables studied influenced the synthesis of tridymite to some extent, the concentration and nature of the nucleation agent were identified as the key parameters to optimize the synthesis process. As a result of this research, a synthetic silica product with high crystalline tridymite phase content was successfully obtained, which could be deemed suitable for use as a secondary reference material in the quantification of crystalline silica, given the lack of reference materials for this kind of structure.