Sciencemadness Discussion Board

What type of vessel to use for MELTING NaOH or KOH at 1200C?

beerwiz - 29-5-2020 at 00:26

I want to run some experiments with molten NaOH and KOH at around 1200'C but I understanding that these molten hydroxides are very corrosive and eat through glass and many other materials.

Which type of material/vessel can I use to melt KOH and NaOH that will withstand temperatures up to 1200'C?

mackolol - 29-5-2020 at 00:29

I believe that crucibles are good for such purposes.

beerwiz - 29-5-2020 at 00:56

Quote: Originally posted by mackolol  
I believe that crucibles are good for such purposes.


A crucible made of what material?

mackolol - 29-5-2020 at 01:11

Quote: Originally posted by beerwiz  

A crucible made of what material?


Just a plain crucible made of ceramic.

Tellurium - 29-5-2020 at 03:07

You could use a nickel crucible, it withstands the 1200°C and it forms a protective layer against the hydroxides.
But as mackolol said plain ceramic should be ok, I also did a lot with molten NaOH and KOH in them ;)

RogueRose - 29-5-2020 at 13:45

I would try making a pottery vessel (with Kaolin clay/Kaolite) and some MgO, possibly some zirconium oxide - all these have very high refractory indexes, are resistant to alkaline and can handle the temp easily.

I'm working on something similar and am using nichrome wire as the heating element built into the crucible, and possibly using a electrode arc for heating from above (I need higher heat than the 2500F available from nichrome

Mateo_swe - 2-6-2020 at 11:37

I just ordered som alumina tubes from china on ebay.
Same company make crucibles in different forms and sizes and very cheap.
They have very high temp ones, just search ebay and you will find what you look for.

metalresearcher - 2-6-2020 at 12:14

Probably these bases will decompose in Na2O resp. K2O and water vapor at these temperatures. Or would you like to let it react with carbon to make the alkali metals ?

morganbw - 2-6-2020 at 13:19

I am only curious on why you wish to use such a high temperature with any of these two salts.

beerwiz - 3-6-2020 at 04:27

I gave the white ceramic crucible a try and it was fine, it endured 2 hours of KOH at 1200'C.

@morganbw I'm making the philosopher's stone. The economy is in shambles and I need the gold to pay my rent. I also need the health benefits from the stone to fight the corona virus, it's been widely known that it gives immortality and cures all ailments.

draculic acid69 - 3-6-2020 at 04:37

What's the need for the high temps?