ESA opens oxygen plant – making air out of moondust

https://www.esa.int/Enabling_Support/Space_Engineering_Technology/ESA_opens_oxygen_plant_making_air_out_of_moondust

A prototype oxygen plant has been set up in the Materials and Electrical Components Laboratory of the European Space Research and Technology Centre, ESTEC, based in Noordwijk in the Netherlands.

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ESTEC’s oxygen extraction is taking place using a method called molten salt electrolysis, involving placing regolith in a metal basket with molten calcium chloride salt to serve as an electrolyte, heated to 950°C. At this temperature the regolith remains solid.

But passing a current through it causes the oxygen to be extracted from the regolith and migrate across the salt to be collected at an anode. As a bonus this process also converts the regolith into usable metal alloys.
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dv said:

ESA opens oxygen plant – making air out of moondust

https://www.esa.int/Enabling_Support/Space_Engineering_Technology/ESA_opens_oxygen_plant_making_air_out_of_moondust

A prototype oxygen plant has been set up in the Materials and Electrical Components Laboratory of the European Space Research and Technology Centre, ESTEC, based in Noordwijk in the Netherlands.

—
ESTEC’s oxygen extraction is taking place using a method called molten salt electrolysis, involving placing regolith in a metal basket with molten calcium chloride salt to serve as an electrolyte, heated to 950°C. At this temperature the regolith remains solid.

But passing a current through it causes the oxygen to be extracted from the regolith and migrate across the salt to be collected at an anode. As a bonus this process also converts the regolith into usable metal alloys.
—-

Nice. And only 950°C.

Looking up web. That’s not so low, after all, some blast furnaces can go down to 900°C but most are hotter.

> ESTEC’s oxygen extraction is taking place using a method called molten salt electrolysis, involving placing regolith in a metal basket with molten calcium chloride salt to serve as an electrolyte, heated to 950°C. At this temperature the regolith remains solid. But passing a current through it causes the oxygen to be extracted from the regolith and migrate across the salt to be collected at an anode. As a bonus this process also converts the regolith into usable metal alloys.

I’d love to see a video of this in action.

Even more, I’d love to see it in person, using earth rocks.
There is an electrochemical series isn’t there. Yes. But how does it work?

Suppose I had a basalt composed of elements Si, O, Fe, Mg, K, Na, Al, Ca, Ti.
Suppose I heated it until partly molten and ran an electric current through it.
Which two elements would be precipitated first at the electrodes?

All I know offhand is that if there’s a salt (eg. MgCl2) in water and a current is passed through then the first elements given off are Cl and H. Why not Mg or O?