Vacuum laser zone refining of titanium towards lunar metallurgy: Experimental and numerical study

Abstract

The development of in-situ utilisation technologies for lunar resources is crucial for future human deep-space exploration. This paper presents a novel vacuum laser zone refining technique aimed at in-situ separation of titanium and iron. The experimental and numerical simulation results indicate that increasing laser power while reducing the melting speed significantly increases the temperature gradient of the melt pool, thereby enhancing molten flow velocity. These factors effectively redistribute the elements at the solid-liquid interface, improving Fe and Ti separation efficiency. Additionally, increasing the number of refining passes can also significantly improve the separation efficiency of Fe and Ti. Under the conditions of 1000 W laser power, 0.05 mm/s melting speed, and 5 refining passes, the separation efficiency of Fe reached 76.5 %. Notably, the maximum molten flow velocity reached 0.157 m/s, which ensured a uniform distribution of Fe in the melting zone. Hence, the proposed vacuum laser zone refining technique is a promising approach for efficient separation of titanium and iron from titanium–iron alloys, providing potential support for deep-space exploration efforts.