5
$\begingroup$

How would you be able to extract aluminium and iron in the moon for example? Is there some electrolytic technique that does not use carbon?

$\endgroup$
  • $\begingroup$ On earth, aluminium is extracted without carbon, it is done using electrolysis. There are other metals besides aluminium which could not extracted with carbon. Magnesium even burns in carbon dioxide gas. $\endgroup$ – Uwe Jan 14 '18 at 17:33
  • 2
    $\begingroup$ the electrodes are carbon. $\endgroup$ – Hobbes Jan 14 '18 at 18:06
  • $\begingroup$ alumiunium is extracted on earth from bauxite, a blend of aluminium hydroxide, iron ore are mostly oxides. On moon, I guess, there are no free water or oxigen, so it is possible to find metallic iron or aluminium $\endgroup$ – Antonio Cipolla Jan 14 '18 at 19:24
  • $\begingroup$ The classic way to extract iron from its ore needs carbon and oxygen.The reduction of iron oxide to metallic iron is done with carbon monoxide. Burning carbon partially to carbon monoxide generates the necessary heat. $\endgroup$ – Uwe Jan 29 '18 at 15:33
5
+50
$\begingroup$

Don Sadoway of MIT has led a team developing molten oxide electrolysis methods for use on the Moon. In 2008 he received a patent for a process using an anode made of iridium and a cathode of tungsten or molybdenum. This apparatus will produce a puddle of molten metals at the cathode, placed at the bottom of a crucible, and bubbles of oxygen around the anode at the top. The metals will be a mixed alloy of all the metals present in the feedstock.

Selection of favorable feedstock from the lunar highlands, comprised mostly of anorthite, CaAl2Si2O8, allows the alloy produced to be mostly aluminum and silicon.

More recently, Sadoway's team have developed an anode made of chromium and iron for use in producing iron on the Moon. This process also has potential application on Earth, as a method of steel production that doesn't release carbon gases as a by-product.

For iron production, other methods have also been investigated. Elemental iron is present in lunar regolith at a level of up to 1% in the maria. Simply passing magnets through a stream of the smallest regolith particles could produce a feedstock very high in iron, but with substantial contaminants.

Processing of ilmenite, FeTiO3, with hydrogen produces water, iron, and titanium dioxide. Concentrations of ilmenite in the maria can be around 10%. Reactors to process ilmenite with hydrogen have been investigated principally as a means of producing oxygen, but iron is another product.

$\endgroup$
  • $\begingroup$ Production of iron on Earth using molten oxide electrolysis needs a lot of electric energy. If this energy was generated burning fossil fuels, carbon oxides are released for that iron. But pure iron without carbon content is not as strong as steel with the optimal amount of carbon, about 2 % of it's weight. Too much carbon will result in brittle cast iron instead of steel. $\endgroup$ – Uwe Jan 26 '18 at 18:16
  • $\begingroup$ @Uwe I'd wondered how the carbon content would be introduced in Sadoway's process. Presumably there is a way to use pure carbon. $\endgroup$ – kim holder Jan 26 '18 at 18:21
  • $\begingroup$ When I think of the traditional blast furnace iron production, mixing the molten iron with powdered carbon should do it. $\endgroup$ – Uwe Jan 26 '18 at 18:56
  • 2
    $\begingroup$ The tensile strength of pure aluminium is very low. An alloy with 95% aluminium, 4% copper, 0.5% magnesium, and 0.5% manganese has a tensile strength of up to 10 times of pure aluminium. Therefore about 5 % of other metalls should be added to get an alloy of very low density but high strength. Some titanium alloys tensile strength is more than 2 times better than pure titanium. Copper for electric cables should be very pure, but structure materials should be suitable alloys instead of pure metalls. $\endgroup$ – Uwe Jan 27 '18 at 10:33

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.