[RogueRose]

Ok, I'm sorry if this is in the incorrect forum but I'm not sure where else to post this.  I want to have the ability to produce NaOH or KOH via electrolysis using a membrane or diaphragm.  The goal is to produce a very high purity product (99%+) would be ideal.  If some of the salt from the brine solution makes it into the final product that isn't the end of the world as the product which is to be made with the bases will include some of those salts.  I would like to be able to produce 1lb of pure NaOH a day and would preferably run the unit 24/7 rather than larger batches less often. 

The bases will be used in solution (percentage of 25-50% most likely) but it will be very nice to be able to distill off the excess water and keep the remainder in solid form.  (the reason I'm doing this is I use both bases in production of products I sell and hate ordering and freight charges)

As for the Cl and H2 byproducts of the cell, I have plans for these.

My biggest problem in designing the cell are finding specs for how to do this process at a high efficiency and making sure not to design in any flaws.  The membrane seems to be the most important.  I read that asbestos membranes were used but I can't find any of those anymore (how can they limit this use for applications like this??).  I have been pointed towards Nafion (TM) membranes, made by DuPont I believe, but those are ridiculously expensive.  I suppose I could justify the cost as long as I can guarantee the cell will function.  Are there other alternatives available for a membrane which is obtainable without being employed at NASA or the CDC, lol??  Suggestions?  (If anyone is interested in developing a cell like this, I'm interested in working together, maybe splitting costs for membranes).

I plan on using distilled H2O along with very pure NaCl or KCl for the brine solutions.

I guess the other two major issues are cathode/annode and construction of the cell body.  I have read that the cath/annode can be graphite while others say they must be titanium, SS and or some MMO of some type.  My head is kind of spinning here. 

As for the body of the cell, from what I have read it doesn't seem to be under much pressure (maybe a PSI or 2) so I am wondering is something like HDPE may work or another base resistant plastic.  I know SS is very resistant to NaOH so I guess that would work as well, but that requires more equipment to manufacture. 

If anyone has any experience with the Chloralkali process, please let me know some of the in's and outs.  I've looked over hundreds of diagrams/images but they are all so basic and don't really give details about material composition. 

Finally, I would really like to know if there are other electrolysis processes I can do with this setup and what other compounds could be produced (obviously using different raw materials). 

[Enthalpy]

Hi MansCraft!

Producing NaOH and KOH isn't very useful, since they're available commercially for cheap.

Did you check the necessary current? For 454g=11,4mol NaOH you need 1.1MC electricity, so in a day it requires 25A. While this current isn't uncommon, it does require a proper design: electrodes with a big area, decent bath cooling, and so on.

Usual stainless steel doesn't resist salt. Chloride ions are corrosive for it. Marine stainless steel is the absolute minimum - and in electrolysis cells, the reactions are much more aggressive than what the compounds would let guess.

Hdpe yes.

Asbestos is phased out in its main applications, so production lines have closed, and all products become harder to find.