Hi, I was wondering if anyone could help. I was shopping today and found some "Lo-Salt" and it said low Sodium content, so I looked to see
what it contained out of interest.
It contains 66% Potassium Chloride and 33% Sodium Chloride. I was wondering if there was an easy way to separate these two compounds as the KCl would
be useful to me, and as it was so cheap would be a good source of it.
I cant think of anyway chemically to separate them, but alternatively some sort of way to separate by their weight difference might work? Not sure.
Any help would be appreciated, thanks!chemoleo - 24-8-2005 at 11:50
Let me guess, is it for precipitation with NaClO3?
Anyways, I think there was a thread on this already... couldn't find it though. Maybe try google. But essentially, you can do careful
crystallisation... and that's about the only practical one. YOu could use the fact that one salt is better soluble in i.e. Ethanol than the
other. It sure is bothersome.
[Edited on 24-8-2005 by chemoleo]chromium - 24-8-2005 at 11:53
Solubility of NaCl is almost independent of temperature. KCl on contrary is much more soluble in hot than in cold water. You have to saturate very hot
water with mix of NaCl and KCl, then let it cool. Precipitate is almost pure KCl.kyro8008 - 26-8-2005 at 13:00
Thanks for the quick responce, I did as you said and it seemed to go well. I did a flame test and unfortunetly did'nt see much lilac, but ive
always found K flame tests a pain to see anyway.
Apart from molten electrolysis is there another way to find if it is potassium?
Thankyou.12AX7 - 26-8-2005 at 13:35
Purify it again if you want, sodium shows up at very low precentages.
There would be Na present for two reasons: 1. evaporation during crystallization, causing NaCl to fall out, 2. excess NaCl after draining the KCl
crystals.
BTW, does anyone know how the equilibrium works on a situation like this? For instance, boil water with an excess NaCl + KCl mixture. KCl is more
soluble, so it dissolves in preference to NaCl, but does it "salt out" and prevent much (if any) NaCl from dissolving? Or does the NaCl
cause it to salt out? Does it dissolve (and salt out likewise, if any) depending on the ratio of surface area?
Timchromium - 26-8-2005 at 14:09
Flame test is so sensitive to sodium that even minutest amount of it will turn flame yellow no matter what other substances there are. So its no help
here. It will probably work if you recrystallise your KCl some more times.
There are ways to make sure your salt is KCl and not NaCl - such as exploring crystals or measuring specific gravity - but why to test? Just use it!chromium - 26-8-2005 at 15:41
to 12AX7: NaCl and KCl both dissolve in remarkable quantities. If temperature is 100C and we take 100g of water then liquid phase over mix of both
salts will contain 27.5g of NaCl and 35.3g KCl after equilibrum is reached. If temperature is 10C those numbers are 30.6g and 12.9g respectively. So
obviously NaCl will not precipitate if hot solution cools down.
I have lot of tables that describe equilibrum in various complex solutions. As much as i know those are just measurement data. To be honest i do not
know can what theory lies behind this.darkflame89 - 27-8-2005 at 00:03
Just like to ask, regarding the conversion of NaClO3 to KClO3, whether i can use KMnO4 to convert instead of the KCl, as KCl is such a pain to
seperate from NaCl....I have pure KMnO4 so I would easy to just add KMnO4 instead of going through all the steps of separating KCl.IPN - 27-8-2005 at 00:24
Just use the salt mix as is. No need to purify as the NaCl just stays in solution and KClO3 will precipitate. Recrystallize the KClO3 few times if you
want it free of sodium salts.NeutralIon - 27-8-2005 at 16:30
A couple of other sources for KCl that might be easier to purify:
From a garden supply/ agricultural store -- they may have it as "Muriate of Potash". I have usually seen it with the granules a rusty brown
color due to the the impurity [or anti-caking agent] which appears to be an iron oxide or hydroxide, and which is insoluable so easier to separate.
It is also slightly magnetic. Price usually around $1.20 (US) a pound.
If you live in an area that gets snow in the winter look for KCl as an ice melter -- considered more "environmently friendly" around lawns
and gardens than NaCl. I have found this to be a better source -- purer, and cheaper, about $0.40 to $0.45 a pound. Probably can use "as
is" for KClO3 manufacture.ChemicalBlackArts - 27-8-2005 at 18:56
If you can procure any sodium cobaltinitrite (Na3Co(NO2)6), that can be used to seperate any potassium ions from solution, as it will precipitate the
wholly insolube complex K3Co(NO2)6. The compound is awfully useful in qualitative analysis.neutrino - 27-8-2005 at 19:55
Fascinating, but not helpful in our case. Purified cobalt compounds are outside the ameteur chemist's price range, I'm afraid.12AX7 - 27-8-2005 at 21:50
Ok ok ok, perchloric acid.
TimQuibbler - 2-9-2005 at 04:48
Just thought I would throw this one in:
KCl is radioactive
NaCl is notdarkflame89 - 2-9-2005 at 06:11
KCl radioactive? You must be kidding, we must all be irradiated to burnt chops by now by all the Lo-sodium salt.Tacho - 2-9-2005 at 06:32
No, he's not kidding. KCl is radioactive.
Not radioactive enough to worry, though. You get more rads from other sources around you.Quibbler - 2-9-2005 at 06:43
Yeah but if I sprinkle it on my food and eat it, the potassium will come into VERY close contact with my body. I suppose much will enter the blood
stream and exit through the kidneys.
Stick with high sodium salt.
I've tried putting solid KCl next to a Giger counter I got 40 to 50 counts per minute. The background count was about 8 counts per minute.neutrino - 2-9-2005 at 07:05
That's not really that much of a difference, IMO.
The radioactivity is from the .012% of naturally-occuring K-40.The_Davster - 2-9-2005 at 17:57
Quote:
Originally posted by neutrino
Fascinating, but not helpful in our case. Purified cobalt compounds are outside the ameteur chemist's price range, I'm afraid.
Actually, in a rather recently produced chemistry set that I acquired, it contains 10g of a 25% CoCl2 mix with NaCl. I had 2 bottles of this so the
last few days I have worked it up to a pure cobalt(II) nitrate solution which is currently evaporating to get the crystals.
EDIT: Checked brauer, the compound mentioned which would ppt potassium is a rather simple synth from cobalt nitrate. When I get the cobalt nitrate
crystals I may give a synth of that a try.
[Edited on 3-9-2005 by rogue chemist]unionised - 3-9-2005 at 04:17
"Yeah but if I sprinkle it on my food and eat it, the potassium will come into VERY close contact with my body. I suppose much will enter the
blood stream and exit through the kidneys.
Stick with high sodium salt. "
Be sure to avoid food that contains carbon too.
On a practical note, while buying cobalt to prepare pure potassium compounds would work, it would be easier to just buy KCl.
