SUMMARY

Lunar in-situ resource utilization is essential for maintaining human presence on Moon. The lunar soil is a valuable source for metals/metalloids as they consist of metal/metalloid oxides. This work focuses on reducing these oxides via carbothermal reduction to valuable metals/metalloids such as Si and Fe that are useful for building industrial and scientific infrastructures on Moon. Due to the lack of atmosphere, concentrated solar irradiation is a reliable heat source to drive such thermochemical reactions with high temperature capabilities. Carbothermal reduction requires carbon as the reductant for the benefit of reducing reaction onset temperatures compared to direct thermal heating and can be found on Moon in the form of methane or human waste upon colonization. Activated carbon is used as the reductant in this investigation. This proposed work aims to answer two major research questions: (1) What metals/metalloids can be extracted from lunar regolith simulants via carbothermal reduction? (2) Are the extraction processes feasible? To answer these questions, a series of experiments under inert and ultra-high vacuum environments, and low-vacuum environment coupled with High Flux Solar Simulator (HFSS) are conducted. The samples and volatiles are characterized using solid-state surface material characterization tools to identify and quantify experimental products. Thermodynamic analysis was conducted prior to experimentation to predict reaction spontaneity and metals/metalloids favorability as a function of temperature and pressure.