Metals Preparation and Oxygen Extraction from NEU-1 Lunar Regolith Simulant by Solid Cathode Electrolysis at Low Temperature

Extracting metals and oxygen from lunar soil provides an essential material foundation for lunar exploration. In this paper, the solid-state cathode electrolysis method was employed, using a Pt anode to successfully electrolyze the NEU-1 lunar simulant at 650 ℃ to produce metal and oxygen. The characteristics and variation patterns of the products at both the cathode and anode during electrolysis were investigated. The results showed that the cathode current efficiency was 37.21%, and the cathode products were divided into outer, middle, and inner layers. The outer layer consisted of yellowish-grey particles with a metallic luster, featuring a smooth surface and a dense structure. It primarily consisted of various metallic phases such as Fe, Al-Si, and Fe-Si, with mass fractions of Fe, Al, and Si being 6.37%, 47.23%, and 27.31%, respectively. The intermediate layer presented as a water-insoluble, grey-black crust characterized by high porosity and a relatively loose structure, mainly comprising Li₂SiO₃ and LiAlSiO₄. The inner core appeared as grey-black particles with a rough surface, forming a loose, flocculent or coral-like structure, and was predominantly composed of Li₂SiO₃, LiAlSiO₄, LiAlSi₂O₆, as well as SiO₂, MgO, and CaFeSi₂O₆. Meanwhile, O₂ was evolved at the anode, and the anode current efficiency reached 54.66% within the first 2 hours. In conclusion, this technology enables a low energy consumption approach for extracting metals such as Fe, Al, and Si as well as O₂ from the lunar regolith at a low temperature of 650 ℃. This implies that this method has potential for application in future lunar exploration activities.