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Author: Subject: can stainless steel be used as a container for chloro akali cell ?
chemistry4frog
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[*] posted on 30-8-2023 at 09:13
can stainless steel be used as a container for chloro akali cell ?


chloro alkali cell for Nacl to HCL and Naoh generation.

The membrane will be ionemer cement casted into a stainless steel pot, with mmo anodes on each side of the ionemer cement.

Was going to use plastic 5 gal bucket at first but worried the plastic will damage. Would stainless be resistant enough?

[Edited on 30-8-2023 by chemistry4frog]
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Tsjerk
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[*] posted on 30-8-2023 at 09:53


Stainless steel and HCl are not compatible, it will rust before your eyes.

[Edited on 30-8-2023 by Tsjerk]
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[*] posted on 30-8-2023 at 12:15


Quote: Originally posted by Tsjerk  
Stainless steel and HCl are not compatible, it will rust before your eyes.

[Edited on 30-8-2023 by Tsjerk]


no the cell does not experience hydrochloric acid. the cell only does electroylsis of salt water and collects hydrogen and chlorine gas which is piped away to be burned.



[Edited on 30-8-2023 by chemistry4frog]
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Rainwater
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[*] posted on 30-8-2023 at 13:08


There are many side reactions that can occur. Adding a soluble metal to the mix will likely create chloride and hydroxide salts which will lower the efficiency of the cell and contaminate the product up to the point of a containment breach.

If you use a high quality stainless steel alloy, it will last longer, but not much.

Get you a big pickel jar, use rtv caulk to fashion a lid and your set




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[*] posted on 30-8-2023 at 15:30


What about a high value resistor connected to negative plate, for a weak cathodic protection bled off main process? Thereby protecting the main tub against corrosion and spoiling the solution with extra ions leached from the material.

Trusting glass and plastic for something that can get hot when ignored, not a great Idea. Love the convenience of glass, but I don't trust it.

Not usually a popular choice from experience. I've suggested similar things to a number of people on a number of occasions IRL and get a sideways look. Happy to just bury a sacrificial bar and walk away.
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[*] posted on 31-8-2023 at 05:47


If cathodic protection worked like that, i would be out of a job. 75% of my work is replacing corroded parts. If you use the proper materials for the application, you will have an appratus that last indefinitely.

Soda glass is acceptable, it can handle temps of 100c, thermal gradients of 30c and is corrosion resistant to chlorate electrolysis and its byproducts(HCl, H2, Cl2, HClO)

You can always up the minimum and use borosilicate or quartz.
Plastic will work aswell, but will degrade with time/temp. And mixing it with an oxidizer is usually not a good idea.

I chose a 1gal pickel jar because it was free, big, chemically resistant, and free.
But to each their own




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chemistry4frog
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[*] posted on 31-8-2023 at 06:54


ok i will look into glass containers, however:

what material is used industrially for chloro alkali cells?

I have a hard time believing they use glass, or plastic ?
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[*] posted on 31-8-2023 at 11:08


HDPE plastic



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khlor
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[*] posted on 2-9-2023 at 04:33


Yes, it can, if your question relates to as "if it works or not" . I did once, and give good current density. I built a stainless steel can as cathode and container. Inside of it had and anode chamber with a diaphagm and anode and cathode chambers were separated. I got over 2A with a 5V supply.

Now, as to why it is not a good idea...

Overtime the can got fragile and broke like glass and the solution on the cathode was supposed to be NaOH but I found it was a yellow chromate and dichfomate solution. The worse is the chlorine did not even leaked from the anode and no chlorine had contact with the steel part, my design made sure of that.

So yeah, it works, but it is no good and not long term... cathodic protection can only deliver you from so much oxidation!

Plus, high alkaline solutions tend to leach chromium from stainless, i guess they can leach zinc and even tin as well.

[Edited on 2-9-2023 by khlor]




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[*] posted on 2-9-2023 at 07:09


would passivation with nitric plus citric (or maybe just hydrofluoric) acid help?



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[*] posted on 2-9-2023 at 07:19


Quote: Originally posted by Rainwater  
If cathodic protection worked like that, i would be out of a job. 75% of my work is replacing corroded parts. If you use the proper materials for the application, you will have an appratus that last indefinitely.

Soda glass is acceptable, it can handle temps of 100c, thermal gradients of 30c and is corrosion resistant to chlorate electrolysis and its byproducts(HCl, H2, Cl2, HClO)

You can always up the minimum and use borosilicate or quartz.
Plastic will work aswell, but will degrade with time/temp. And mixing it with an oxidizer is usually not a good idea.

I chose a 1gal pickel jar because it was free, big, chemically resistant, and free.
But to each their own


Please keep in mind this is not a chlorate cell it is a chlor-alkali divided cell, it is not supposed to heat up. With that said, your insight is a very appreciable contribution.




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[*] posted on 2-9-2023 at 07:28


Quote: Originally posted by Sulaiman  
would passivation with nitric plus citric (or maybe just hydrofluoric) acid help?



I hardly believe that would be the case with stainless steel. My story doesn't end in there. Stainless or not, the can got all rusty... chloralkali is very agressive and does not forgive anything. Passivation may work with other metals, nickel, titanium, but stainless not because of the principle work of stainless is that chromium oxide will form a protective layer. The problem lies in tbe fact that chromium oxides can and will dissolve in highly alkaline environments which is the case for cathode chamber of the chloralkali cell.

Edit 1: text correction

[Edited on 2-9-2023 by khlor]




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[*] posted on 2-9-2023 at 08:05


I use 3d printed pvc cells now. A few dialysis pumps and some solution containers.
Printing in pvc is nasty, btw.
https://www.sciencemadness.org/whisper/viewthread.php?tid=15...

A simpler solution is using plumbing 90 fittings. like this one

Specifically, one with a male-female connection so a membrane can be squeezed in between the fittings and sealed with ptfe thread sealant. So it doesn't leak.
They are engineered to withstand a wide range of ph's and harsh chemical environments.

Edit:
Quote: Originally posted by khlor  
Please keep in mind this is not a chlorate cell it is a chlor-alkali divided cell

Sorry, my brain slipped into a different gear


[Edited on 2-9-2023 by Rainwater]




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[*] posted on 2-9-2023 at 08:37


Quote: Originally posted by Rainwater  
I use 3d printed pvc cells now. A few dialysis pumps and some solution containers.
Printing in pvc is nasty, btw.
https://www.sciencemadness.org/whisper/viewthread.php?tid=15...

A simpler solution is using plumbing 90 fittings. like this one

Specifically, one with a male-female connection so a membrane can be squeezed in between the fittings and sealed with ptfe thread sealant. So it doesn't leak.
They are engineered to withstand a wide range of ph's and harsh chemical environments.

Edit:
Quote: Originally posted by khlor  
Please keep in mind this is not a chlorate cell it is a chlor-alkali divided cell

Sorry, my brain slipped into a different gear


[Edited on 2-9-2023 by Rainwater]


So it is as I suspected, PVC is a better material, I had planned to do it with PVC back in the days, but I had personal issues and now work is consuming my life, so it had been post ponned for a long time. One of these days I’ll get back on tracks and do a design with PVC, it can withstand good temperatures, resists well against acidc and alkaline environments and it ks not easily attacked by chlorine gas on chlorine reactive species. Well, thag is from my reseach back then, though I do not nor will have 3d printing capabilities in the foreseeable future, I had planned to do all with PVC piping... so it will be all good , I hope.




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[*] posted on 2-9-2023 at 09:31


Quote: Originally posted by khlor  
Quote: Originally posted by Rainwater  
I use 3d printed pvc cells now. A few dialysis pumps and some solution containers.
Printing in pvc is nasty, btw.
https://www.sciencemadness.org/whisper/viewthread.php?tid=15...

A simpler solution is using plumbing 90 fittings. like this one

Specifically, one with a male-female connection so a membrane can be squeezed in between the fittings and sealed with ptfe thread sealant. So it doesn't leak.
They are engineered to withstand a wide range of ph's and harsh chemical environments.

Edit:
Quote: Originally posted by khlor  
Please keep in mind this is not a chlorate cell it is a chlor-alkali divided cell

Sorry, my brain slipped into a different gear


[Edited on 2-9-2023 by Rainwater]


So it is as I suspected, PVC is a better material, I had planned to do it with PVC back in the days, but I had personal issues and now work is consuming my life, so it had been post ponned for a long time. One of these days I’ll get back on tracks and do a design with PVC, it can withstand good temperatures, resists well against acidc and alkaline environments and it ks not easily attacked by chlorine gas on chlorine reactive species. Well, thag is from my reseach back then, though I do not nor will have 3d printing capabilities in the foreseeable future, I had planned to do all with PVC piping... so it will be all good , I hope.


what is your yeild in your chloroalkali cell. my new plan is a glass fish tank, since the membrane is going to be 1 square foot, i cannot use pvc pipe for such a large area.

[Edited on 2-9-2023 by chemistry4frog]
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[*] posted on 2-9-2023 at 10:17


Quote: Originally posted by chemistry4frog  
Quote: Originally posted by khlor  
Quote: Originally posted by Rainwater  
I use 3d printed pvc cells now. A few dialysis pumps and some solution containers.
Printing in pvc is nasty, btw.
https://www.sciencemadness.org/whisper/viewthread.php?tid=15...

A simpler solution is using plumbing 90 fittings. like this one

Specifically, one with a male-female connection so a membrane can be squeezed in between the fittings and sealed with ptfe thread sealant. So it doesn't leak.
They are engineered to withstand a wide range of ph's and harsh chemical environments.

Edit:
Quote: Originally posted by khlor  
Please keep in mind this is not a chlorate cell it is a chlor-alkali divided cell

Sorry, my brain slipped into a different gear


[Edited on 2-9-2023 by Rainwater]


So it is as I suspected, PVC is a better material, I had planned to do it with PVC back in the days, but I had personal issues and now work is consuming my life, so it had been post ponned for a long time. One of these days I’ll get back on tracks and do a design with PVC, it can withstand good temperatures, resists well against acidc and alkaline environments and it ks not easily attacked by chlorine gas on chlorine reactive species. Well, thag is from my reseach back then, though I do not nor will have 3d printing capabilities in the foreseeable future, I had planned to do all with PVC piping... so it will be all good , I hope.


what is your yeild in your chloroalkali cell. my new plan is a glass fish tank, since the membrane is going to be 1 square foot, i cannot use pvc pipe for such a large area.

[Edited on 2-9-2023 by chemistry4frog]


Please, clarify your question, you mean yield based on watts? And what yield ? Chlorine , Sodium hydroxide ? Hydrogen? HCl?

Try and take a look in this thread there is a section with calculations. It is not what you want but might give you an idea, plus, I recall from my series of experiments that on chloralkali alone I managed to get 78% efficiency on grams of chlorine produced per watt spent at 5v power supply. I hope to shed some light. Please keep in mind that the experiments on the thread I linked are in a undefined halt since I lack time and resources to dedicate to it. So it is an incomplete work and i might not even help you because all math is based around the yield on HCl production and not the cloralkali cell.




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[*] posted on 2-9-2023 at 10:22


Depending on the design of your cell, a conductive container can act as a "short circuit".
That's not what you want.
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