Sciencemadness Discussion Board

How to make KOH (aka) Potassium Hydroxide

xcv826 - 11-5-2014 at 09:26

CaCl (calcium chloride) + NaOH (sodium hydroxide) = CaOH (calcium hydroxide)

CaOH + K2CO3 (potassium carbonate) = CaCO3 ([calcium carbonate] is precipitated out of solution) + KOH (left in solution)

(After filtration) dry out/heat in steel medium-steel pan, collect the KOH.




Potassium carbonate can be made from KOH, but this would be redundant to do. So i suggest an alternate method:

Wood ash or aged banana peels. Wood ash has approx. 10% potash (various mixtures of potassium salts, mainly KOH). Potash can be obtained through the process of burning hardwood to ashes, specifically. Hardwood includes oak, cherry, and maple. There are many other hybrids of soft-hard wood, and lesser and greater density hardwood, but the aforementioned are the most common, cheap, and easy to get.
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Additional notes:

CaCl can be made with addition of hydrochloric acid to CaCO (Calcium Carbonate) or bought at retail stores such as Walmart or pool supply stores.

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Help:

If you need any links/sources to this information, if you don't believe it, than post a request. Also, if you need any help with how to make the individual chemicals, that i didn't cover, or didn't cover enough, or need a video on how to make them, post a request. If you need help, POST a REQUEST.

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Side note:

Flaming or demeaning this post or being disrespectful will result in reporting you. Also, please say on topic.
Thank you, regards Arch

elementcollector1 - 11-5-2014 at 09:44

I believe this has been covered before, most notably in an old-school chemicals thread (the name escapes me).
In addition, despite the potassium % content of banana peels being higher than other fruits, the yield is still ridiculous after combustion, to the point where electrolysis of KCl under special conditions is more feasible economically for the amateur.

numos - 11-5-2014 at 09:47

This is interesting but not economical, you can buy pounds of KOH for a few dollars online, and it's not a restricted chemical (as far as I know). The way I see it, if you have access to NaOH, then KOH shouldn't be too difficult to acquire.

Nonetheless, I suppose doing it in large batches may be economical.

blogfast25 - 11-5-2014 at 09:55

Quote: Originally posted by numos  
Nonetheless, I suppose doing it in large batches may be economical.



Nope. Processes based on potash (K2CO3 leached from wood ashes) have been abandoned as being uneconomical with respect to modern processes.

@xcv826:

Please use correct formulas: CaCl2, Ca(OH)2.

xcv826 - 11-5-2014 at 10:16

I know it’s not economical, i just posted for others who don't have access to KOH readily. No doubt this is interesting, if extenuating circumstance prevent you from accessing the chemical in a more economical way or conventional way.

xcv826 - 11-5-2014 at 10:25

@elementcollector1

Do you at least know search terms for the thread? And electrolysis of KCl makes potassium chlorate, perchlorate, and hydroxide. I’ve seen many videos on each chemical all electrolysis KCl, there is no clarification as to how to make which chemical or if their all made together, it’s quite aggravating. Does anyone have clarification on this? Please and thank you.

and thank you elementcollector1.

Manifest - 11-5-2014 at 10:34

When you boil down the KOH you will make potassium carbonate with the CO2 in the air.

xcv826 - 11-5-2014 at 10:39

Could i still use the solution of KOH with out drying? Because i only really need it, when im using it, in solution only.

xcv826 - 11-5-2014 at 10:41

Quote: Originally posted by numos  
This is interesting but not economical, you can buy pounds of KOH for a few dollars online, and it's not a restricted chemical (as far as I know). The way I see it, if you have access to NaOH, then KOH shouldn't be too difficult to acquire.

Nonetheless, I suppose doing it in large batches may be economical.



@numos So it CAN be economical, only in large batches though?

elementcollector1 - 11-5-2014 at 11:00

Quote: Originally posted by xcv826  
@elementcollector1

Do you at least know search terms for the thread? And electrolysis of KCl makes potassium chlorate, perchlorate, and hydroxide. I’ve seen many videos on each chemical all electrolysis KCl, there is no clarification as to how to make which chemical or if their all made together, it’s quite aggravating. Does anyone have clarification on this? Please and thank you.

and thank you elementcollector1.


Sadly, no - I've been searching for a while. I believe it was last seen in the Whimsy section.

Which chemical is made depends on the setup. KOH can only be made if the anode and cathode are separated via a salt bridge (to prevent the Cl2 reacting with the KOH). KClO is made by keeping the anode and cathode in the same solution, at low temperatures. KClO3 can be made in the same manner as KClO, with specific anodes (MMO, Pt or even carbon work for this) and higher temperatures (via bringing the electrodes closer together - in fact, cooling is probably needed for this as well). KClO4 is formed by doing the same thing to a starting solution of KClO3 instead of KCl.

xcv826 - 11-5-2014 at 11:41

Quote: Originally posted by elementcollector1  
Quote: Originally posted by xcv826  
@elementcollector1

Do you at least know search terms for the thread? And electrolysis of KCl makes potassium chlorate, perchlorate, and hydroxide. I’ve seen many videos on each chemical all electrolysis KCl, there is no clarification as to how to make which chemical or if their all made together, it’s quite aggravating. Does anyone have clarification on this? Please and thank you.

and thank you elementcollector1.


Sadly, no - I've been searching for a while. I believe it was last seen in the Whimsy section.

Which chemical is made depends on the setup. KOH can only be made if the anode and cathode are separated via a salt bridge (to prevent the Cl2 reacting with the KOH). KClO is made by keeping the anode and cathode in the same solution, at low temperatures. KClO3 can be made in the same manner as KClO, with specific anodes (MMO, Pt or even carbon work for this) and higher temperatures (via bringing the electrodes closer together - in fact, cooling is probably needed for this as well). KClO4 is formed by doing the same thing to a starting solution of KClO3 instead of KCl.


thank you soo much for the clarfication, too bad i cant access whismy section :(.

But i was wondering if you or someone has a video on the salt bridge setup and making KOH with it?

numos - 11-5-2014 at 12:16

Quote: Originally posted by xcv826  
Quote: Originally posted by numos  
This is interesting but not economical, you can buy pounds of KOH for a few dollars online, and it's not a restricted chemical (as far as I know). The way I see it, if you have access to NaOH, then KOH shouldn't be too difficult to acquire.

Nonetheless, I suppose doing it in large batches may be economical.



@numos So it CAN be economical, only in large batches though?


Perhaps material wise in the long run. But the amount of work, clean up, and time required makes it difficult to describe it as "economical".

Like blogfast25 mentioned this method is obsolete. Electrolysis may take more to initially setup, but once you got it going is becomes very cheap to make product.

xcv826 - 11-5-2014 at 12:22

@numous thank you very much. great help. :)

Zyklon-A - 11-5-2014 at 13:08

I don't know of a video on potassium hydroxide, but this instructable shows a pretty simple method that uses a salt bridge. It uses NaCl and make sodium hydroxide, but will work the same way with potassium chloride. I can also vouch for this method as I have followed the instructions and it worked. It's still cheaper for me to buy sodium hydroxide (or potassium hydroxide), but if I couldn't, I would use this method.

[Edited on 11-5-2014 by Zyklonb]

Magpie - 11-5-2014 at 14:28

For xcv826: http://www.sciencemadness.org/talk/viewthread.php?tid=4800

Primordial chemicals

[Edited on 11-5-2014 by Magpie]