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Author: Subject: Hydroclhloric acid (and HCl gas) production from salt (NaCl) electrolysis (small scale Chloralkali process)
experimenter_
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[*] posted on 29-4-2016 at 10:21


Quote: Originally posted by XeonTheMGPony  
I built this system at 15 when I was far less interested int he science then I am now days.
Mercury and chlorine gas at the age of 15 ... :cool: hehe

Quote: Originally posted by XeonTheMGPony  

the brine tank, Same bolt configuration, but the positive electrode was finely coiled SS welding wire that was 1.5 inches from the bottom of the tank.

As I understand it, you used SS welding wire as the anode where chlorine is generated. Did you find it to be resistant to chlorine? Maybe I could replace the carbon electrode.

Thanks for sharing with us your findings.
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[*] posted on 29-4-2016 at 12:59


it held up well enough when I was running it, cant remember much more then that been so long.

and as for the stuff I was playing with at that age that was the safest! Advantages of growing up in remote heavy industry ;)
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[*] posted on 4-5-2016 at 12:34


Quote: Originally posted by MrHomeScientist  
I've done the "flower pot cell" before as an experiment to produce NaOH. It worked, albeit very slowly. The real problem I found is how to permanently seal the hole in the bottom of the flower pot. Tape falls off and caulk quickly degrades in the basic environment!


I tried the same thing last fall. My wife found a bisque clay shot glass at a craft store with no hole in the bottom, the type you'd paint and bake in a kiln. It seemed to work well but the NaOH production was really, really slow.
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[*] posted on 11-5-2016 at 13:46


I was wondering you could just bubble the chlorine into the water, making HCl and HClO, and simultaneously expose the water to UV, I read somewhere that the HclO then turns into Hcl and o2 or just leaves the solution as chlorine gas.(?)
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[*] posted on 23-6-2016 at 04:10
My attempt at chlor-alkali process:v0.1


Greetings sciencemadness community,

For a while now, I have contemplated and tested various chloralkali setups, and seem to have found one that somewhat works.
The electrolytic cell is an empty ice-cream box with a total volume of 1.2 L. The cell is partitioned by an asbestos fiber diaphragm, held in place by epoxy resin glue. I originaly tried filter paper, which proved vulnerable to the strongly alkaline conditions. Asbestos,however, works well.
The cathode component is 4 times larger that the anode compartment, to accomodate more NaOH. For the cathode, a stainless steel strip with a surface area of 20 cm2 was used. The anode is a carbon rod taken from a battery. The anode corrodes in the acidid condictions, forming a paste of carbon particles on the surfac3 of the anode compartment.
Power is provided by 3 parallel PSUs on the 12V rail. After running the electrolysis for 6 hours at around 6A, circa 1L of 1.1M NaOH solution has been produced. This corresponds to 81.1% efficiency.
Once I get my gas-collection system running, I will start producing HCl by collecting the gases and exposing them to UVC.
Current problems with the setup:
1)Erosion of the graphite electrode. Here to stay until I get my PbO2 done;
2)Copper cable providing current to the anode is attacked by the Cl2 gas, producing CuCl2.
Would love to hear any thoughts, suvgestions, etc!

Zandins



[Edited on 2-7-2016 by Bert]

Please re-size your pictures to just large enough to show the details relevant to your post!!! You blew the margins, are you a mass nerderer or something...

http://www.sciencemadness.org/talk/viewthread.php?tid=66853#...

[Edited on 2-7-2016 by Bert]

[Edited on 2-7-2016 by Bert]
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Jstuyfzand
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[*] posted on 5-7-2016 at 13:43


Quote: Originally posted by Zandins  
Greetings sciencemadness community,

For a while now, I have contemplated and tested various chloralkali setups, and seem to have found one that somewhat works.
The electrolytic cell is an empty ice-cream box with a total volume of 1.2 L. The cell is partitioned by an asbestos fiber diaphragm, held in place by epoxy resin glue. I originaly tried filter paper, which proved vulnerable to the strongly alkaline conditions. Asbestos,however, works well.
The cathode component is 4 times larger that the anode compartment, to accomodate more NaOH. For the cathode, a stainless steel strip with a surface area of 20 cm2 was used. The anode is a carbon rod taken from a battery. The anode corrodes in the acidid condictions, forming a paste of carbon particles on the surfac3 of the anode compartment.
Power is provided by 3 parallel PSUs on the 12V rail. After running the electrolysis for 6 hours at around 6A, circa 1L of 1.1M NaOH solution has been produced. This corresponds to 81.1% efficiency.
Once I get my gas-collection system running, I will start producing HCl by collecting the gases and exposing them to UVC.
Current problems with the setup:
1)Erosion of the graphite electrode. Here to stay until I get my PbO2 done;
2)Copper cable providing current to the anode is attacked by the Cl2 gas, producing CuCl2.
Would love to hear any thoughts, suvgestions, etc!

Zandins



[Edited on 2-7-2016 by Bert]

Please re-size your pictures to just large enough to show the details relevant to your post!!! You blew the margins, are you a mass nerderer or something...

http://www.sciencemadness.org/talk/viewthread.php?tid=66853#...

[Edited on 2-7-2016 by Bert]

[Edited on 2-7-2016 by Bert]


12V seems a bit high, have you tried 5V?
Corrosion should be less.

May I ask what route to PbO2 you are taking?
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[*] posted on 6-7-2016 at 03:07


Quote: Originally posted by Jstuyfzand  


12V seems a bit high, have you tried 5V?
Corrosion should be less.

May I ask what route to PbO2 you are taking?


12V probably is overkill, although they were necessary to push any sizable current through the cell due to the small surface area of the carbon rod.
As for the PbO2, I plan to cast a lead plate and electroplate it with PbO2 in H2SO4 solution in-situ. There are varying accounts on the feasibility of this method, so I intend to try it out before moving to more sophisticated approaches.
The general problem seems to be the flaking of the PbO2 layer in strongly corrosive conditions. However, if the coating would be grown thick enough to prevent any of the substrate from being exposed, I conjecture it could hold, at least in a chlor-alkali cell(opposed to chlorate of perchlorate). Meanwhile I am also looking into platinized titanium - if any were to be found at a reasonable price, all the aforementioned problems would be eliminated.
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[*] posted on 6-7-2016 at 03:48


I saw something about graphite rods and anodes being corroded faster in basic environments, I guess chloralkali would be less harsh on the electrodes since the anode bath stays neutral when you are using a separated cell.
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[*] posted on 6-7-2016 at 07:23


Quote:
I saw something about graphite rods and anodes being corroded faster in basic environments

A graphite cathode in a chlorate cell is quite unaffected by the high pH which arises in a working cell!

Acidity at the anode is damaging, obviously...

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[*] posted on 6-7-2016 at 07:30


Have you tried just plain ol' titanium for the anode of a chlorate cell?

Reason I ask is I have several hundred square foot worth of 16 gauge titanium CP2 sheet that I can easily shear up.




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[*] posted on 6-7-2016 at 07:37


Quote: Originally posted by Fleaker  
Have you tried just plain ol' titanium for the anode of a chlorate cell?

Reason I ask is I have several hundred square foot worth of 16 gauge titanium CP2 sheet that I can easily shear up.


Titanium will passivate and no current will flow, wont work.

By the way, how are you all using these asbestos plates as diaphrams when that stuff is carcinogenic and prohibited?
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[*] posted on 6-7-2016 at 07:38
Passivation


As far as I am aware, titanium passivates in anodic conditions as it is oxidised to TiO2,which is nonconductive. Therefore, it can only be used as a cathode.
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