Fluor
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Electrolytic Citric acid Oxidation
I tried to dissolve Aluminium in a citric acid solution. I used a Anode made from Aluminium and a Cathode made from Copper. At 36V, bubbling occurred
at the Cathode, but no staining was visible at the Anode. The solution turned yellow. After some of the water evaporated, clear, colorless crystals
where formed and the solution crystallized out nearly completely, only a few drops of a yellow solution remained.
The crystals readily dissolve in water and act acidic in aqueous solution. When heating the crystals up, they start to melt, than give off water and
at least start to decompose with a smell of citric acid, leaving behind some soot.
I can hardly imagine that they are pure citric acid, as there was indeed bubbling at the cathode, but no bubbling at the anode, and the anode wasn't
oxidized.
I am grateful for every answer.
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unionised
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It sounds like you (re)discovered the process of anodizing aluminium
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Fluor
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OK, so the Aluminium has been oxidized to Al2O3.
And the Yellow color appeared due to impurities?
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