Extraction of Aluminum from Lunar Regolith through Molten Salt Electrolysis

Abstract

This paper presents the methodology, development, and results of an end-to-end regolith-to-metal concept for producing aluminum in-situ on the lunar surface, namely, the Lunar In-Situ Aluminum Production through Molten Salt Electrolysis (LISAP-MSE) method. Using electrolytic reduction, aluminum oxide (i.e., alumina) can be reduced into aluminum and oxygen via electrolysis in a molten salt bath. A steady supply of hydrogen chloride could allow this in-situ resource utilization (ISRU) method to supply several necessary materials consumed in the electrolytic reduction step of the process to produce bulk aluminum metal, oxygen, water, and silica from anorthite abundant in lunar highland regions. In this paper, we present experimental steps and results of thermally and chemically reducing anorthite, an aluminum-rich mineral commonly found in the lunar highlands, and testing of an electrolytic cell that was produced “in house”. The results show that the end-to-end process yielded bulk metallic spheroids with > 85% aluminum by mass.