Separation of oxygen and metals from Mars soil simulant via molten salt electrolysis

Mars is a long-term target for human exploration in the future. On the basis of the demands of space exploration and in situ resource utilization, Martian soil simulant NEU Mars-1 was applied for metal extraction and oxygen preparation in 50.9 wt% KF-49.1 wt% AlF 3 molten salt at 750 °C, and the dissolution and electroreduction behaviors of Martian soil simulants were studied via the isothermal saturation method and electrochemical techniques, respectively. The results revealed that the concentrations of SiO 2 , Fe 2 O 3 , and TiO 2 in the molten salt reached 6.09 %, 0.25 %, and 0.17 %, respectively, when the dissolution was in equilibrium. The reduction processes of various ions in Martian soil simulants were as follows: Fe(III) was first reduced to Fe(II) and Fe, Si(IV) was reduced to Si(II), and Fe(II) was reduced to Fe, and finally, Al and Si were codeposited. NEU Mars-1 was electrolyzed with an Fe-Ni anode and liquid Al as the cathode in molten salt. The purity of the anode gas O 2 was 95.41 %, whereas an Al-Si-Fe-Ti alloy containing 12.13 wt% Si, 3.00 wt% Fe and 0.17 wt% Ti was obtained at the cathode.