Proving the viability of an electrochemical process for the simultaneous extraction of oxygen and production of metal alloys from lunar regolith

Abstract

The development of an efficient process to simultaneously extract oxygen and metals from lunar regolith by way of in-situ resource utilisation (ISRU) has the potential to enable sustainable activities beyond Earth. The Metalysis-FFC (Fray, Farthing, Chen) process has recently been proven for the industrial-scale production of metals and alloys, leading to the present investigation into the potential application of this process to regolith-like 2 materials. This paper provides a proof-of-concept for the electro-deoxidation of powdered solid-state lunar regolith simulant using an oxygen-evolving SnO2 anode, and constitutes the first in-depth study of regolith reduction by this process that fully characterises and quantifies both the anodic and cathodic products. Analysis of the resulting metallic powder shows that 96% of the total oxygen was successfully extracted to give a mixed metal alloy product. Approximately a third of the total oxygen in the sample was detected in the off-gas, with the remaining oxygen being lost to corrosion of the reactor vessel. We anticipate, with appropriate adjustments to the experimental setup and operating parameters, to be able to isolate essentially all of the oxygen from lunar regolith simulants using this process, leading to the exciting possibility of concomitant oxygen generation and metal alloy production on the lunar surface.

Interactions of molten salts with cathode products in the FFC Cambridge Process

“…This condition is in contrast to that of the electro-reduction of TiO 2 , whose perovskitization results in the increased volume of the solid phase and hence blockage of the pores in the oxide cathode, impeding the removal of O 2− and the whole electrolysis. Continuous CaTiO 3 electrolysis via Reaction (16) will lead to the accumulation of CaO in the molten salt. However, one can in principle combine Reactions ( 16) and ( 13) to form a closed loop in which CaO is cycled and functions like a "phase change catalyst" to accelerate the electrolysis of TiO 2 .…”

“…In the past two decades, world-wide research and development have confirmed the scientific principle and technical feasibility and flexibility of the process for the extraction of almost all metals listed in the periodic table and their alloys from their respective oxide or sulfide precursors [6][7][8][9][10][11][12][13][14]. In addition, the FFC Cambridge Process has versatile applications in other fundamental and industrial areas, such as near-net shape manufacturing of metallic artifacts of complex structures, medical implants, oxygen generation on the moon, capture and electrolytic conversion of carbon dioxide (CO 2 ) to various forms of carbon, e.g., carbon nanotubes, carbon monoxide (CO), and hydrocarbon fuels (C n H 2n+2 , n < 10), and rechargeable molten salt metal-air batteries [15][16][17][18][19][20][21][22].…”

Direct electrochemical production of pseudo-binary Ti–Fe alloys from mixtures of synthetic rutile and iron(III) oxide

“…The process has since been shown to be capable of reducing many different metal oxides, including those of tantalum, chromium and cerium [2][3][4]. Mixed-metal oxides can also be reduced simultaneously, allowing for the direct production of alloys, as well as more novel materials like high-entropy alloys and those derived from lunar regolith simulant material [5][6][7][8][9].…”

Shielded dumbbell L5 settlement

“…As shown recently [15], the so-called FFC Cambridge electrolytic process can be used to separate earthly, lunar or asteroid rock into oxygen gas and a solid residue comprising metals and silicon. The oxygen can be used as Electric Propulsion propellant [16].…”