The reduction process of lunar regolith simulant was designed to obtain metallic iron (Fe) and utilize lunar resources, focusing mainly on the effect of titanium dioxide (TiO 2 ) on the recovery of metallic Fe from molten slag. Thermodynamic calculations were conducted to predict the equilibrium phases existing at high temperature upon heating the regolith simulant to 1600°C under an oxygen partial pressure of 10 ¹15 atm, in which the metallic Fe coexisted with the molten slag. Based on these predictions, two steps were applied in the experimental procedure: a reduction step followed by a melting step. The results showed that metallic Fe droplets were obtained by aggregating fine metallic Fe particles in the melting step. The viscosity of molten slag was found to decrease when TiO 2 was added to the regolith simulant, but the recovery ratio® defined as the weight ratio of the metallic Fe obtained from the aggregation of fine metallic Fe particles to the total amount of Fe in the regolith simulant®also decreased. The wettability between liquid Fe and molten slag improved upon increasing the TiO 2 content in the latter. These results indicate that wettability exerts a substantially more dominant effect than the viscosity of molten slag does in the recovery of metallic Fe from regolith simulant.

Numerous pump systems are applied to industries including power plants; among these, desulfurization transfer pumps are severely eroded by slurry, and require periodic replacement of internal impeller and wear plate parts. When directed energy deposition(DED) in the additive manufacturing process is used to repair parts, it is possible to repair entire parts or sections of them. If there is no discontinuity or inventory of parts, this process is expected to be utilized often in the future. In this study, a deposition test and physical property evaluation were carried out using the DED process to repair wear resistance pump parts for desulfurization transfer. Although it is necessary to develop alloys with excellent deposition conditions and compositions similar to those of the base material, this study conducted experiments on commercially available alloy materials. As a result of evaluating various materials, it was found that a powder composed of an iron-based system had characteristics similar to those of the material to be repaired.