REFINING THE SOL-GEL SYNTHESIS METHOD OF INTERMEDIATE, NANO-SCALE OLIVINE

The purpose of this study was to develop a more reliable and refined process for the production of specific intermediate compositions of olivine at the nanoscale. The mineral olivine, (Mg,Fe)₂SiO₄, can have ranging composition between end-members Fayalite (Fe₂SiO₄ -or- Fo0) and Forsterite (Mg₂SiO₄ -or- Fo100), with any combination of Fe and Mg possible in intermediate compositions (e.g. Mg_0.5Fe_1.5SiO₄ -or- Fo25). Previous work by Cannon (2014) was able to show that synthesis of intermediate compositions is possible; however, that study was limited in scope in that few experiments were performed. In this study, several new experiments have produced intermediate composition olivine using a modified sol-gel synthesis method. This newly develop method is based on the previous work of DeAngelis et al. (2012) for the synthesis of fayalite and Anovitz et al. (2017) for the synthesis of forsterite. Produced olivine batches have been characterized with use of X-ray powder diffraction (XRD) to verify crystal structure, scanning electron microscopy (SEM) to determine precise composition, and BET surface area analysis to investigate particle size.

The use of well-characterized olivine nanoparticles as starting material in experiments may be significant for several important areas of research. Olivine is a primary component of most of the rocky bodies of the solar system, so studies of weathering rates, mineral reaction, and other thermodynamic properties (e.g. Lilova et al. 2018) will benefit from the samples produced by this project. Several engineering applications, such as CO₂ sequestration via mineral carbonation (e.g. Loring et al. 2015), industrial acid neutralization, and energy storage, are already using, or have the potential to use, olivine nanoparticles. The samples produced by this project will be useful to contribute to these, and other as yet unidentified, olivine-related studies.