Cathodic Reduction Process in Low-Temperature Electro-Deoxidation for Metal Extraction from NEU-2 Lunar Regolith Simulant

The electro-deoxidation behavior of a solid NEU-2 lunar regolith simulant cathode was investigated in a LiCl-KCl-Li 2 O molten salt at 600°C. The process proceeds through the sequential reduction of its major oxide components: iron oxides are preferentially reduced to metallic Fe within 20 min, followed by the formation of Fe-Si and Al-Si intermetallic compounds as electrolysis continues. After 6 h, the product stabilizes into a mixture of metallic Fe and aluminum-silicon alloys, with further electrolysis driving the transformation toward Al-rich phases. The electro-reduction front advances inward with time, leading to a distinct three-layer structure in the final cathode product: a fully deoxygenated outer shell consisting of Al-Si alloy, Fe-Si alloy, and metallic Fe; an intermediate layer with high oxygen content (∼58.2 wt%) containing intermediates such as Li 2 SiO 3 and LiAlSiO 4 ; and an inner core of unreacted oxides resembling the original regolith. This study demonstrates the extraction of metals and oxygen from lunar regolith via molten-salt electrolysis at 600°C, confirming the feasibility of using the FFC Cambridge process for space metallurgy under these thermal conditions. It also uncovers the evolution pattern of the cathodic product over 12 hours, providing a temporal reference for tailoring the final products and opening up new possibilities for the efficient utilization of complex, low-grade ores.