Chemgineer - 9-8-2024 at 08:02
I tried to electrolyse a solution of aluminium chloride, I got 1 amp to flow but then it immediately dropped to 0.2amp and when I tried to raise the
voltage to broiing it back up I popped a capacitor in my power supply.
Is it a bad idea to carry out electrolysis of this salt?
Sorry I seem to have put this in the wrong section.
[Edited on 9-8-2024 by Chemgineer]
Rainwater - 9-8-2024 at 10:01
Electrolysis of aqueous AlCl3 results in a build up of a passivation layer of AlOx and Al(OH)3 on the cathode.
This layer has to be physically removed from my experience.
Gaseous Cl2 with ether escape or be dissolved into the solution and in my situation attack more of the aluminum anode
I use this process to convert scrap aluminum into refractory bricks.
It requires routine beatings in order to be considered a continuous process.
Chemgineer - 9-8-2024 at 10:09
Thanks, so the fact my power supply broke was probably just coincidence then, it has been in a corrosive environment for months.
Rainwater - 9-8-2024 at 17:03
Lets assume there is no short circuit, hydrogen contamination or other obvious cause for the failure.
make sure your vcc is greater that the unloaded voltage of your electrolysis cell.
Meaning that as your reaction runs, the cell can turn into a battery amd due to Murphy law, produce more voltage than your power supply is outputting,
without a diode in series, this can reverse polarity your filtering caps,
Its a rarely encountered issue, because the extra voltage potential will dissipate over time and your cell can not charge more than voltage applied.
Unless you change the conditions, such as adding reagents.
Then the extra umph from the fresh chemicals will cause all sorts of electrical phenomenon until the system becomes heterogeneous.... homogeneous
..... damnit im tryin to sound fancy but cant spell the dam word. Till everything mixes throughly
Chemgineer - 10-8-2024 at 08:42
That's really interesting, I think you are probably right. In future I won't go near max voltage to hopefully avoid it happening again.
Sir_Gawain - 10-8-2024 at 12:47
What is the end goal of the electrolysis, i.e. what chemicals are you trying to produce?
Chemgineer - 10-8-2024 at 14:25
I don't see much information about aluminium chlorate or perchlorate and I wondered why, so just on a small scale I thought i'd electrolyse a small
sample to find out the problems. I found them!
Rainwater - 10-8-2024 at 18:42
http://www.chlorates.exrockets.com/chlorate.html doesnt have anything about alumnium. At a wild guess you would react alumnium with perchloric
acid so im out. That stuff to nasty for me. It can make your lab go boom boom boom.
[Edited on 11-8-2024 by Rainwater]