Recent Advances in Scale-Up Development of Molten Regolith Electrolysis for Oxygen Production in Support of a Lunar Base

Abstract

Previously, we have demonstrated the production of oxygen by electrolysis of molten regolith simulants at temperatures near 1600oC. Using an inert anode and suitable cathode, direct electrolysis (no supporting electrolyte) of the molten silicate is carried out, resulting in the production of molten metallic products at the cathode and oxygen gas at the anode. Initial direct measurements of current efficiency have confirmed that the process offer potential advantages of high oxygen production rates in a smaller footprint facility landed on the moon, with a minimum of consumables brought from Earth. We now report the results of a scale-up effort toward the goal of achieving production rates equivalent to 1 metric ton O2/year, a benchmark established for the support of a lunar base. We previously reported on the electrochemical behavior of the molten electrolyte as dependent on anode material, sweep rate and electrolyte composition in batches of 20-200g and at currents of less than 0.5A. In this paper, we present the results of experiments performed at higher currents (several Amperes) and in larger volumes of regolith simulant (500g) for longer durations of