Concentrating CaO from Lunar Simulant by Calciothermic Reduction Process

The lunar regolith can be utilized as raw materials for constructing lunar bases through the fabrication of lunar cement. However, the low CaO content in lunar regolith presents a challenge for producing silicate cement. This study explores enriching CaO in NEU-1 lunar soil simulant by calciothermic reduction. Non-isothermal differential scanning calorimetry analysis indicated that calcium reacted with Fe2O3, SiO2, and Al2O3 at approximately 808°C, 816°C, and 826°C, respectively. The reaction ratios were 1.1, 1.6, and 0.8, with apparent activation energies of 941.6 kJ/mol, 965.17 kJ/mol, and 547.28 kJ/mol. The products obtained from the calciothermic reduction of lunar soil simulant were CaO, Ca2Si, and AlFe, as analyzed by X-ray diffraction. Increasing the temperature was found to be beneficial to the reaction process, and a suitable reaction temperature of 850°C was determined. X-ray photoelectron spectroscopy analysis showed that the reduction percentages of SiO2 and Al2O3 were 93.01