Molten Regolith Electrolysis: The Extraction of Oxygen from Lunar Regolith

Molten regolith electrolysis (MRE)nbsp;is a high-temperature electrolytic process in which the naturally high-oxide lunar regolith is dissolved in a molten oxide solvent comprising already liquefied regolith and by the action of electric current is dissociated to electrowin liquid metal as a product and oxygen as a by-product. The process involves using an extractor reactor and a refiner reactor. The liquid metals can be extracted in sequence according to the stabilities of their oxides as expressed by the values of the free energy of oxide formation (e.g. Cr, Mn, Fe, Si, Ti, Al, Mg, and Ca). The Moon is rich in mineral resources capable of sustaining the production of oxygen, Si, and a variety of metals, (e.g., Fe, Al, and Ti). However, the extraction of these elements will require the use of rather different processes from those used on Earth 10. For example, mineral beneficiation has been an enduring paradigm in terrestrial extractive metallurgy for economic reasons but the reliance on such unit operations as froth flotation with its attendant consumption of huge quantities of water summarily disqualifies beneficiation from consideration in the lunar setting. To eliminate the need for beneficiation prior to processing and to minimize the import of consumable reagents from Earth, the project team proposes to advance MRE for the production of oxygen using lunar regolith as feedstock that has not been subjected to any form of pretreatment.