Sciencemadness Discussion Board

Cheap and available source of potassium ions

Jstuyfzand - 25-2-2017 at 15:16

I am trying some experiments and projects with potassium soon, ranging from electrolysis of the molten salts to making chlorate.

However, I have not been able to find a cheap (Sodium carbonate cheap) source of potassium salts such as their chloride or carbonate.
fertilizer is often impure with P and N contaminations, and household products such as bleach and baking soda all use Sodium compounds.

Ofcourse I could buy it from a chemistry supplier, but using 99%+ potassium for a displacement reaction....?


Thanks in advance!
(Located in the netherlands btw, so no Wallmart for me.)

anewsoul - 25-2-2017 at 15:30

Have you tried looking for sodium free salt? It should be mostly potassium chloride if there's any stores around that sell it.

macckone - 25-2-2017 at 18:01

There are potassium cubes for water softeners that
are 20+lb bags of potassium chloride (food grade).
Also brewing supply shops stock potassium carbonate
(food grade). And of course sodium free salt as
mentioned above (contains silica and possibly other
compounds). Traditionally potassium carbonate sold
as pearl ash is derived from burning potassium
bitartate (food grade sold as cream of tartar).

m1tanker78 - 25-2-2017 at 18:09

Check your local water softener supply store. They often sell alternative salt that's [mostly] potassium chloride. It's surprisingly inexpensive and comes in 40-60 pound bags.

It may be a long shot but also check with pool supply stores. They'll carry regular salt but ask about sodium-free or similar.

Sodium-free (food grade) salt is another option but is often augmented with salts of other metals .. calcium, magnesium, etc as well as other 'free-flowing' agents. At least that's been my experience.

If you have access to potassium nitrate and sulfuric acid, you could make some nitric acid and keep the potassium sulfate. ;)

j_sum1 - 25-2-2017 at 20:12

Check out soap making supplies too. KOH is often used to make a more liquid soap.

Or, if you want to go for the traditional route you can extract K2CO3 from wood ash (or from burnt banana peels.)

JJay - 25-2-2017 at 20:49

I see pallets of 50-lb sacks of potassium chloride sitting around the entrance of local home improvement stores for use as an ice melter. I'd think something similar would probably be available in the Netherlands, especially from some of the more industrial-type vendors.



Jstuyfzand - 26-2-2017 at 01:14

Great suggestions, thanks alot!
I've considered to buy the salt substitute, but unfortunately it costs a couple of euros per 100grams, and I believe potassium chloride is not something you pay 20 euros for per kilo :D

I'll look around for the water softeners and ice melters, I unfortunately do not have a brewing/soap making shop in close proximity.

EDIT: I love it when I spend an hour looking for potassium pallets / ice melter without result and I google it in english and I get what Im looking for first result at home depot.
In america.



Bloody hell.

[Edited on 26-2-2017 by Jstuyfzand]

macckone - 26-2-2017 at 09:35

Brewing and soap making supplies are going to be
more expensive than ice melter and water softener.
Water softener is the best go to as it is 99%
potassium chloride with the remainder being
sodium chloride and it is food grade. Here in the US
a 40lb (18Kg) can be had for as little as US$20 which
would be about the same 20 euros (plus vat of course).
That is about as cheap as you will find potassium salt.
Fertilizer grade will be cheaper but it requires clean up.

unionised - 26-2-2017 at 11:51

Extraction from wood ash it "free" but time consuming.

I wonder why people use KCl to melt ice. CaCl2 is better, NaCl is cheaper

JJay - 26-2-2017 at 11:55

I have no clue. Some people use MgCl<sub>2</sub>. Supposedly, it is safe for pets. I'm pretty sure most ice melting compounds are safe for pets, but I suppose enough potassium will cause cardiac arrest....

I've also seen urea sold as ice melt.

macckone - 26-2-2017 at 12:32

potassium chloride is better for plants than sodium
chloride and mag chloride. Urea is plant safe (within
reason as it is fertilizer) and pets will ignore it but
it doesn't work well at cold temps.

Here is a page that describes the various ice melters:
http://www.peterschemical.com/break-the-ice-comparison-of-ic...

As they sell these compounds they say they are all
'safe' but anyone with a basic knowledge of gardening
would recognize urea as the 'plant safe' alternative.
This page talks about the plant safety but doesn't include urea:
http://www.gardensalive.com/product/plantsafe-ice-melting/yo...
This article includes urea and recommends acetates for plants:
http://www.washingtonpost.com/wp-dyn/content/article/2010/02...

I personally use calcium chloride because of the
lower temp action, some articles say 5F but
it works well down to -15F. When I lived in the colorado
mountains it mattered. In new mexico not so much.

Sulaiman - 26-2-2017 at 12:47

can you get potassium carbonate ?
e.g. http://www.ebay.co.uk/itm/1Kg-Potassium-carbonate-high-purit...

or more K/$, KOH http://www.ebay.co.uk/itm/1KG-POTASSIUM-HYDROXIDE-FLAKE-CAUS...

ebay.nl http://www.ebay.nl/itm/potassium-hydroxide-flake-caustic-pot...

[Edited on 26-2-2017 by Sulaiman]

volkchemie - 26-2-2017 at 18:59

Quote: Originally posted by unionised  
Extraction from wood ash it "free" but time consuming.


If you have some slaked lime (which is Ca(OH)2 and is usually fairly cheap all around) common in cement sections of hardware store, you can get potassium hydroxide fairly easily by reacting the two together. Basically how potassium hydroxide was produced for soap using potash, but beware that this is extremely messy and like what unionised said, time consuming as it requires a lengthy soak, filtering, and boiling down a large amount of solution. The resulting product I usually got were heavily contaminated and required crystallization.

From there, if you want to recover the hydroxide as a carbonate, simply bubble CO2 into a solution of potassium hydroxide. Or react the hydroxide with hydrochloric acid for the chloride.

Jstuyfzand - 27-2-2017 at 10:38

Quote: Originally posted by volkchemie  
Quote: Originally posted by unionised  
Extraction from wood ash it "free" but time consuming.


If you have some slaked lime (which is Ca(OH)2 and is usually fairly cheap all around) common in cement sections of hardware store, you can get potassium hydroxide fairly easily by reacting the two together. Basically how potassium hydroxide was produced for soap using potash, but beware that this is extremely messy and like what unionised said, time consuming as it requires a lengthy soak, filtering, and boiling down a large amount of solution. The resulting product I usually got were heavily contaminated and required crystallization.

From there, if you want to recover the hydroxide as a carbonate, simply bubble CO2 into a solution of potassium hydroxide. Or react the hydroxide with hydrochloric acid for the chloride.


Time consuming unfortunately, maybe spring will bring some NPK 0-0-60 fertilizer into the stores? (100% potassium)