There was some concern about production of chlorine in the process I was using to remove steel by electrolysis. I thought I would investigate this further.
I made a quick and dirty set-up using steel as anode and stainless steel as cathode (identical to the actual process). I tried it in 1% NaCl solution and the same solution acidified with a "splash" of vinegar. I was going to collect the gases but this proved impractical. Thus I judged the gas production by the number of bubbles produced at each electrode. This is what I found:
1) There was *no* gas production at the anode with either electrolyte. Not a single bubble.
2) There was copious gas production at the cathode. This I take to be hydrogen. I did not light it up to confirm...
3) I changed the anode to copper. Still no gas production.
3) I changed the anode to stainless steel. While there was on-going copious production of hydrogen at the cathode, there was minimal bubble production at the anode with some yellow discoloration. I take this to be chlorine.
Thus with my existing set-up and given the scale of the operation, production of chlorine does not appear to be a concern.
That's good. I was using carbon electrodes (from dry cell batteries) to get the Cl2. With C rods the bubbles of Cl2 are quite pronounced, though the solution around the electrode seemed to go a little "scummy", although this may have been caused by contaminant on the electrode itself.
Your posts on here prompted me to take my boys out to the shed and make some hydrogen & chlorine for a bit of fun.
There's a discussion on different electrode types here:
That's good. I was using carbon electrodes (from dry cell batteries) to get the Cl2. With C rods the bubbles of Cl2 are quite pronounced, though the solution around the electrode seemed to go a little "scummy", although this may have been caused by contaminant on the electrode itself.
Your posts on here prompted me to take my boys out to the shed and make some hydrogen & chlorine for a bit of fun.
There's a discussion on different electrode types here:
I am not sure if the statement about copper on that forum is based on theory or actual observation. I certainly did not get any Cl on the copper anode.
The one video I saw of both gases being produced was with graphite on both electrodes. Even there it seems there was less chlorine produced than hydrogen.
Today I pretended to be anaemic and got some Ferrous Sulphate. Interesting and disappointing:
1) It is quite difficult to dissolve, particularly as the tabs had what I take to be enteric coating.
2) I could not get the same current at the same voltage, in fact with the same size electrodes and the distance between them I managed barely over 1 Amp with 30 V pushing it.
3) There was a lot of sediment which interestingly started as white. There was a lot of hydrogen production with consequent foaming which is a pain.
4) After about 20 minutes the current started dropping off. Either the cathode was getting dirty or the ions in the electrolyte were getting depleted.
5) After 30 minutes there was a decent deep etch, probably (eyeball measurment!) 0.003-0.005".
6) The resist on this occasion was enamel paint which in my past experience tends to stick to the substrate better than most other things. Today, however, it started peeling off when I began to wash the piece. Not sure why as on the back of the piece the same paint was hard to remove with acetone!
7) Not surprisingly, in view of (6), there was a fair bit of foul-biting.
I think I shall stick to the salt/vinegar mixture in future. A thought about the hydrogen production: The idea is to disperse it as it is being formed, however, with all the foaming I am concerned that the gas gets trapped in the foam and exists there in an unhealthy concentration. A spark near the bowl could be quite interesting. It is a small amount but still...I watched someone on Youtube pass a mix of H2 and O2 through a soapy water bath, making bubbles, which he then had an assisstant scoop and hold while helit them up. A pretty decent bang!
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