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Author: Subject: Finally I isolated Sodium (and potassium)
metalresearcher
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[*] posted on 29-6-2020 at 11:55
Finally I isolated Sodium (and potassium)


I have some Li metal and found a Youtube video of a guy distilling K from KCl + Li metal.
I repeated this and made a steel tube retort with a copper tube attached to it ending in a beaker with lamp oil. I have no pure KCl, but diet salt (2/3 KCl and 1/3 NaCl). I heated the retort to about 800 C, I checked temperature with an infrared pyrometer pointed at the red hot retort and avoided getting it hotter than 850 C to prevent too much Na (bp 889 C) evaporation. K boils at 768 C, and so I hoped that the not too high temperature gives priority to K vaporizing over Na, but still too much Na distilled over.
After ten minutes beads of shiny metal appeared and after 20 minutes I shut it down.
The beads coalesced to a single one of 15mm across and after cooling down to room temp. it is still liquid, so it must be NaK.
I threw a small bead into water and it was bright yellow, so Na dominates.

EDIT: But why is there still so much Na ? I know (see Cody's Lab) that with Na one can free K from KCl, so when I have a *mixture* of two parts KCl and one part NaCl, then K has priority over Na due to its lower boiling point (and thus higher vapor pressure ai 800 C ) ?

RX606070.JPG - 2.5MB RX606071.JPG - 1.5MB RX606072.JPG - 1.4MB Na-water.gif - 2.2MB

[Edited on 2020-6-29 by metalresearcher]
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Ubya
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[*] posted on 29-6-2020 at 12:25


well you already have a direct source for NaK :)

maybe you could try a few recrystallizations to get a higher concentration of potassium chloride (iirc potassium chloride shoul be less soluble in methanol)





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B(a)P
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[*] posted on 29-6-2020 at 12:26


Nicely done and thanks for the write up. Could you please include a picture of two of you retort?
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metalresearcher
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[*] posted on 29-6-2020 at 21:47


As requested, here pictures of my retort.

It is a 3/4" 3mm thick steel pipe, 80mm long, squeezed together and welded and the other end welded to a 3/8 steel knee which is screwed to a brass 3/8 => 15mm copper tube adapter. The copper pipe of 25cm long ends in the beaker with oil. To refill it, I unscrew the brass adapter.

BTW, I have lots of KBr, will that also work with Li ?

RX606075.JPG - 1.8MB RX606073.JPG - 1.9MB

[Edited on 2020-6-30 by metalresearcher]
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Belowzero
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[*] posted on 29-6-2020 at 22:00


Nice experiment !

KCl can be cheaply obtained from fertilizers.
Might be a better source than diet salt ;)

Did you measure the yield?


[Edited on 30-6-2020 by Belowzero]
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metalresearcher
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[*] posted on 30-6-2020 at 09:17


Quote: Originally posted by Belowzero  
Nice experiment !

KCl can be cheaply obtained from fertilizers.
Might be a better source than diet salt ;)

Did you measure the yield?



Still low, about 2g NaK from 20g NaCl/KCl 1:2 mix and 2g Li metal.

But I prepared for the next step. As I don't have KCl, but do have K2CO3, I dissolved 20g K2CO3 in 100ml 10% HCl solution until sizzling stopped. Then I evaporated the water and dried it thoroughly it resulted in 21g KCl. Together with 2g Li this should yield a few grams of K.
KCl + Li => LiCl + K
75.5 7 42.5 40 (molecular weights)
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metalresearcher
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[*] posted on 1-7-2020 at 10:53


And now I got potassium in nice silvery beads !
I used KCl obtained from K2CO3 dissolved in HCl solution which I dried out. I used 20g of KCl and 1.9g Li metal, heated to 750 - 800ºC in a steel retort and the distilling ending in a beaker with lamp oil.
But still it contains some Na due to some yellow tinge in the flame. I don't know where from.

https://www.metallab.net/jwplayer/video.php?v=L2NsaXBzL0tDbC...
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