This is one possible way to get oxygen for Lunar mare basalt.
- Chemical reaction
European Space Research and Technology Centre (ESTEC)
ESTEC has built a prototype oxygen plant in Noordwijk, Netherlands . This process was developed by Metalysis; however, in their process the oxygen is an unwanted by-product . The process is based on the FCC process .
- Use molten molten calcium chloride salt as an electrolyte .
- Crush regolith (or basalt) into powder .
- Heat to 950°C .
- The regolith will remain solid at this temperature .
- Place regolith, contained in a metal basket, into the molten electrolyte at the cathode (carbon composite catalyst) .
- Pass a current through the electrolyte .
- Oxygen is extracted from the regolith, migrates across the electrolyte, and is collected at the anode (made of graphite) .
- 15 hours to extract 75% of the total oxygen .
- 50 hours to extract 96% of the total oxygen .
- The oxygen is then vented into the atmosphere in their current setup but eventually they will have it go into a storage system .
- A by-product of this process is a “tangle of different metals” .
- Lower temperature and energy consumption because the regolith remains in a solid state instead of melting .
- Much of the oxygen can be extracted .
- No toxic by-products .
- Minimal processing. The feedstock is a powder and remains a powder at the end of the process .
- Silent .
- A by-product is a metal sponge that can be crushed, milled, washed, and dried into a variety of metal powders .
- Calcium chloride is considered pretty safe.
- No cast basalt as a by-product (because the regolith isn’t melted).
- Calcium is pretty common but chlorine isn’t. That will have to be imported from Earth.
- I haven’t found data on if the CaCl2 is consumed in the process.
- Able to be constructed/maintained locally
- Minimal reliance on Earth for reagents
- Operable in 1 SLHA
- Ease of maintenance
- Energy input
- Electrolyte heated to 950°C .
- Heat output
- No hazardous materials are produced
- Processes that extract more than just oxygen are preferred
- Process leaves behind a metal sponge from which a variety of metals can be obtained .
- Other uses for the reagents
- European Space Agency (ESA) – ESA opens oxygen plant – making air out of moondust. (www.esa.int/Enabling_Support/Space_Engineering_Technology/ESA_opens_oxygen_plant_making_air_out_of_moondust)
- Metalysis (www.metalysis.com/technology/)
- Phys.org – Oxygen and metal from lunar regolith. (phys.org/news/2019-10-oxygen-metal-lunar-regolith.html)
Need to read
- Lomax 2019. Planetary and Space Science Vol 180