Clonejeffie
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Cheap nitrates to potassium nitrate
Hello I want to make KNO3 with cheap nitrates such as Ca(NO3)2, NH4NO3 or NaNO3. I am thinking of just using calcium nitrate because I can get 25
pounds for 29.99 and I would like some help figuring out how to separate products from the reaction Ca(NO3)2+2KCl----->CaCl2+2KNO3
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j_sum1
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I don't see any simple one-step route to do what you want here. The problem with what you have stated is that both CaCl2 and KNO3 are extremely
soluble. Separation of one from the other by means of precipitation is going to be problematic.
Probably your most direct route would be to make HNO3 from your calcium nitrate and then react with K2CO3 or KOH to get the potassium nitrate. Not
sure that would be worth your time or effort. It might simply be easier to source KNO3 some other way. Why specifically do you need
potassium nitrate?
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greenlight
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If you want to use calcium nitrate I think it would be preferable to react it with potassium sulfate:
Ca(NO3)2 + K2SO4 - CaSO4 + 2KNO3
The calcium sulfate produced is much less soluble than calcium chloride so would be easier to seperate the potassium nitrate out.
Or if you want to use the ammonium nitrate there is this:
NH4NO3 + KCl ----> NH4Cl + KNO3
There is a full video of it here:
https://science.wonderhowto.com/how-to/make-potassium-nitrat...
[Edited on 12-4-2017 by greenlight]
Be good, otherwise be good at it 
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Deathunter88
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Quote: Originally posted by j_sum1  | | I don't see any simple one-step route to do what you want here. The problem with what you have stated is that both CaCl2 and KNO3 are extremely
soluble. Separation of one from the other by means of precipitation is going to be problematic. |
I would argue that KNO3 is significantly less soluble than CaCl2, enough for precipitation to work. At 0C KNO3 is almost 5 times less soluble than
CaCl2.
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j_sum1
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| Quote: Originally posted by Deathunter88 | | Quote: Originally posted by j_sum1 | | I don't see any simple one-step route to do what you want here. The problem with what you have stated is that both CaCl2 and KNO3 are extremely
soluble. Separation of one from the other by means of precipitation is going to be problematic. |
I would argue that KNO3 is significantly less soluble than CaCl2, enough for precipitation to work. At 0C KNO3 is almost 5 times less soluble than
CaCl2.
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OK. I was going from the top of my head. So maybe you are right. However, both are pretty soluble so there will be losses.
It is nice that KNO3 has a steep solubility curve which aids crystallisation of pure crystals.
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Fulmen
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No reason to guess:
https://en.wikipedia.org/wiki/Solubility_table
Below 20°C KNO3 is the least soluble salt, above that it's KCl. So it's possible but not really practical.
We're not banging rocks together here. We know how to put a man back together.
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yobbo II
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http://www.nakka-rocketry.net/knsyn1.html
google
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Neme
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Imho Ca(NO3)2 + K2CO3 would be the best bet.
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Clonejeffie
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I could not find K2NO3 so would KOH work?
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Clonejeffie
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Also it turns out the calcium nitrate I ordered is actually ammonium calcium nitrate so can I still use KOH or KCL?
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Clonejeffie
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Clonejeffie
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Is there anyway of using this Ammonium calcium nitrate?
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JJay
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Elch Science did it here: https://www.youtube.com/watch?v=B8hzgXyxTQw
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ave369
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Use a mixture of KOH and K2CO3. It will provide a one-shot removal of both offending ions. Calcium will precipitate with carbonate, and ammonium will
be destroyed by OH- and a little boiling.
Smells like ammonia....
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clearly_not_atara
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a mixture of cacl2 and water remains liquid much lower than 0C, which is missing from the table. Extrapolating the slope of the
solubility curve tells me that you should be able to cool to -15 C and precipitate most of the KNO3.
However if you have K2CO3 it makes more sense to use this, collect limestone, and then evaporate to dryness.
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Σldritch
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Coincidentally i made calcium nitrate from ammonium calcium nitrate today by dissolving it in tap water, filtering it, and heating to drive of the
water and ammonium nitrate. I ended up with a very white powder, not sure about the purity though.
Another method might be reacting it with cold ammonia solution to precipitate calcium hydroxide and then reacting the calcium hydroxide with more
ammonim calcium nitrate to form ammonia gas and calcium nitrate. Point is it would only need a small amount of ammonia or calcium hydroxide to start
it and you could get separation without much else.
Might not be very relevant because you could probely use ammonium calcium nitrate instead of calcium nitrate. Especially if you use potassium
hydroxide to drive of the ammonia.
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ninhydric1
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NurdRage did a video on reacting ammonium nitrate and potassium chloride then recrystallizing potassium nitrate at low temperatures:
https://www.youtube.com/watch?v=xOjtlIxYYbs
NileRed also did a video using calcium ammonium nitrate (which seems to be the one on hand) and potassium chloride:
https://www.youtube.com/watch?v=X8lGF41BYjA&t=2s
This relies on ammonium nitrate being a strong oxidizer. Not sure about the other nitrates though. Alternatively, you could look around your local
hardware store for stump remover that contains potassium nitrate. Its usually relatively pure.
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