Opylation - 3-11-2020 at 05:13
I’m only posting this because I thought aluminum could not be reduced electrically but was curious when I say that ammonia’s reduction potential
was higher than aluminum. It is interesting to think about electrically reducing aluminum back to a metal especially since the method of producing
aluminum metal from alumina is done electrical but in liquid cryolite at high temperature. When I was looking at different metals and their production
using electrolysis I quickly found aluminum would not work because it’s reduction potential is higher than that of water, meaning water will be
reduced before aluminum will. But I found a cool article on the reduction of alumina in liquid ammonia using solvated alkali metals like potassium as
the electrolyte. I’m not sure of the logistical practicality of using this method but it is interesting, to say the least. Curious as to what you
guys think.
Attachment: Electrochemistry of aluminum in liquid ammonia.pdf (2.7MB)
This file has been downloaded 266 times
DraconicAcid - 3-11-2020 at 07:57
I doubt you could reduce the alumina by electrolysis in liquid ammonia, because I would be amazed if alumina would dissolve in liquid ammonia. Liquid
ammonia is a poor solvent for ionic compounds due to its low polarity, unless the ions involved will form coordination compounds with ammonia.
Aluminum doesn't.
metalresearcher - 3-11-2020 at 23:36
If this were true, commercial isolation of aluminum would use this process rather than the energy intensive and CO2 belching Hall Heroult process.
But recycling of aluminum scrap is getting more and more viable as there is a lot of Al waste.
Opylation - 7-11-2020 at 21:29
I'm back after a short break due to school. Them pesky midterms. After looking over the article a little further it looks like they were using
electrolysis to remove surface oxidation on aluminum metal in order to activate for further reactions like dissolution into liquid ammonia by forming
aluminum triamide. Seems I jumped the gun a little. An interesting article though