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Backyard Chemist
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Ammonium Nitrate from Calcium Ammonium Nitrate
The other day I bought an instant cold pack, for the ammonium nitrate. However, the cold pack contains calcium ammonium nitrate, for ammonium nitrate
is restricted where I live, due to its explosive properties. I tried out a process to isolate this ammonium nitrate but it proved unsuccessful. Here's
what happened:
1. Added about 200 grams of the calcium ammonium nitrate to boiling water.
2. The solution appeared a milky, somewhat yellowish color after a few minutes.
3. I noticed undissolved residue at the bottom of the solution.
4. Began to filter using an improvised filtration system. ( A rag under a sieve which was over a flask.)
5. There was still some undissolved particles settled at the bottom of the flask, so I filtered a few more times, which in turn showed little to no
difference.
6. Boiled the solution once more, and left it out to cool. I still noticed there was still some undissolved particles at the bottom of the flask.
After a few minutes I put the solution in the fridge to allow the Ammonium nitrate to crystallize. Nothing happened for an hour and a half. At that
point, I decided to put it in the freezer for a bit, but to no prevail. The solution appeared to look the same. At the point, I just chucked the
whole thing out, willing to try it again with another 200 grams or so.
So what went wrong? I have to guesses..
1. I did not use a proper filtration apparatus. Should I use coffee filter for the next attempt?
2. I did not cool it down properly to allow the crystallization process to occur. I figure i should place the beaker with solution in a bigger beaker
full of ice, as ive seen in similar videos.
By the way, don't go on about telling me to research it myself, as i've already done so, and can't find anything on the subject.
The purpose of me doing this experiment is to obtain ammonium nitrate and react it with potassium chloride , in order to yield potassium nitrate. And
no, please do not tell me to try a different process involving different chemicals. I want to do it this way and explore the process of chemistry.
Any help is appreciated!
[Edited on 30-12-2014 by Backyard Chemist]
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Thread Moved
30-12-2014 at 01:19 |
blogfast25
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Quote: Originally posted by Backyard Chemist  | By the way, don't go on about telling me to research it myself, as i've already done so, and can't find anything on the subject.
[Edited on 30-12-2014 by Backyard Chemist] |
There is at least one thread on this subject on THIS forum. Search deep and you'll find it. I believe the OP was successful in his attempt. There may
be more threads on it here, as it's a popular subject
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Backyard Chemist
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Ive tried my best, but I cant find anything on this matter...
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blogfast25
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Here's one about NaNO3 from CAN.
http://www.sciencemadness.org/talk/viewthread.php?tid=39612#...
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blogfast25
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| Quote: Originally posted by Backyard Chemist | 6. Boiled the solution once more, and left it out to cool. I still noticed there was still some undissolved particles at the bottom of the flask.
After a few minutes I put the solution in the fridge to allow the Ammonium nitrate to crystallize. Nothing happened for an hour and a half. At that
point, I decided to put it in the freezer for a bit, but to no prevail. The solution appeared to look the same. At the point, I just chucked the
whole thing out, willing to try it again with another 200 grams or so.
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CAN is a double salt of calcium nitrate and ammonium nitrate: simply boiling/dissolving it, filtering it and cooling will at best produce purified
crystals of CAN and NOT ammonium nitrate.
The whole point to a double slat if that both salt crystallise out together as the double sulphate.
To extract NH4NO3 from CAN, you need to replace the Ca<sup>2+</sup> by the equivalent quantity of
NH<sub>4</sub><sup>+</sup>.
You can do this by adding the right amount of ammonium nitrate to a solution of the CAN:
Ca(NO3)2(aq) + (NH4)2SO4(aq) ==== > CaSO4(s) + 2 NH4NO3(aq)
... because CaSO4 (gypsum) is poorly soluble in cold water.
[Edited on 30-12-2014 by blogfast25]
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Bert
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Could you specify the manufacturer' name and product name/number on the bag of CAN fertilizer, or post a clear photo of the label?
Some formulations include additives designed to interfere with filtering solutions. A glue type material and fine powdered ash from coal fired power
plants is common-
See here :
http://www.google.com/patents/US7785553
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hissingnoise
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| Quote: | | Could you specify the manufacturer' name and product name/number on the bag of CAN fertilizer, or post a clear photo of the label?
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The CAN fertiliser I'm familiar with was simply a mixture of ammonium nitrate and calciferous clay ─ this was easily removed by settling and
decanting . . .
Cold pack AN may contain calcium nitrate in the mix, rather than carbonate!
[Edited on 31-12-2014 by hissingnoise]
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Backyard Chemist
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Yeah, I'm using a cold pack!
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Backyard Chemist
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But it is possible, I've heard, to isolate the ammonium nitrate from the CAN by boiling at filtering..
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blogfast25
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In the chemical sense of the word, CAN corresponds to the following double salt hydrate:
5Ca(NO3)2•NH4NO3•10H2O
From this no NH4NO3 can be obtained by boiling and filtering, for the reason I explained above.
But as others above have noted, CAN is a term that is often rather loosely and in some cases it may be possible to just leach out the NH4NO3.
And if hissingnoise is correct and you are using a cold pack you will not be able to do that: both calcium nitrate and ammonium nitrate are very
soluble in water and no separation can be obtained that way.
[Edited on 31-12-2014 by blogfast25]
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hyfalcon
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Use ammonium sulfate to displace the calcium ion. It's hard to stop at the right point in the addition.
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Xenoid
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| Quote: Originally posted by Backyard Chemist |
... The purpose of me doing this experiment is to obtain ammonium nitrate and react it with potassium chloride , in order to yield potassium
nitrate... |
I'm not exactly sure why you are trying to obtain ammonium nitrate from the cold pack when what you ultimately want is potassium nitrate! The cold
pack solution contains Ca++, NH4+ and NO3- ions. Just add a saturated solution of your KCl and cool to say -5 oC, KNO3 as the least soluble species at
this temperature will crystallize out. This is called a double dissolution reaction.
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DraconicAcid
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In the short answer thread, I suggested adding potassium carbonate. Calcium carbonate will precipitate and can be filtered out, and the carbonate
should (at least upon boiling) deprotonate the ammonium ion, and the heat should drive off the ammonia. That will leave a solution of potassium
nitrate.
Please remember: "Filtrate" is not a verb.
Write up your lab reports the way your instructor wants them, not the way your ex-instructor wants them.
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macckone
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Best method is adding ammonium sulfate. You have to add extra water as we have all dealt with insoluble calcium salts.
If you have sufficient water and allow to settle between additions, you can detect the end point when a drop of ammonium sulfate added no longer
produces a precipitate.
This procedure from thought emporium works:
https://www.thoughtco.com/make-ammonium-nitrate-from-househo...
By Anne Marie Helmenstine, Ph.D.
Updated June 03, 2020
Fireworks season is coming up, so before I get into the new fireworks projects, I wanted to cover the synthesis of a common chemical used for
pyrotechnics: ammonium nitrate. Another fun project to try with ammonium nitrate is to make an endothermic reaction. You can buy ammonium nitrate as a
pure chemical or you can collect it from instant cold packs or some fertilizers. You can make ammonium nitrate by reacting nitric acid with ammonia,
but if you don't have access to nitric acid (or don't want to mess with it), you can make ammonium nitrate from readily available home chemicals.
Gather Materials
You will need:
138 g sodium bisulfate (found with pool chemicals, used to lower pH)
1 mole equivalent of a nitrate salt... any of the following
85 g sodium nitrate (common food preservative)
101 g potassium nitrate (which you can buy or make yourself)
118 g calcium nitrate (tetrahydrate)
ammonia (common household cleaner)
methanol (optional, which may be found as HEET fuel treatment)
Ingredients
Dissolve the sodium bisulfate in the mininum amount of water (about 300 ml).
Dissolve your nitrate salt in the minimum amount of water (amount depends on the salt).
Mix the two solutions.
Next you want to neutralize the solution, which is quite acidic. Stir in ammonia until the pH of the mixture is 7 or higher. Use a pH meter (or pH
paper). Reacting ammonia, sodium bisulfate, and nitrates will give you sodium sulfate and ammonium nitrate.
Sodium sulfate and ammonium nitrate have different solubilities in water, so boil the solution to get the sodium sulfate to crystallize. Remove
the liquid from heat when crystals of sodium sulfate form in the bottom of the pan.
Chill the solution in the freezer to get as much of the sodium sulfate as possible to drop out of the solution.
Run the solution through a filter (coffee filter or paper towels) to separate the solid sodium sulfate from the ammonium nitrate solution.
Allow the ammonium nitrate solution to evaporate, which will give you ammonium nitrate, with some sodium sulfate impurity. This is 'good enough'
for most chemistry projects.
If you want to further purify the ammonium nitrate, dissolve it in about 500 ml of methanol. The ammonium nitrate is soluble in methanol, while
the sodium sulfate is not.
Run the solution through a filter, which will give you sodium sulfate on the filter and a solution of ammonium nitrate.
Allow the methanol to evaporate from the solution to obtain crystalline ammonium nitrate.
Safety Information
The chemicals used in this project are smelly and corrosive, so this project should be performed under a fume hood or outdoors. As always, wear
gloves, eye protection, and appropriate clothing. Some of the reagents and the final product are flammable or are oxidizers, so keep the chemicals
away from open flames.
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AngelEyes
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Seems like a hell of a faff to get Ammonium Nitrate.
Also, "I wanted to cover the synthesis of a common chemical used for pyrotechnics: ammonium nitrate" - Common?? Ammonium Nitrate is
never used in pyro. It's not a colourant, is too hygroscopic and can potentially explode.
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ManyInterests
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I am bumping this thread up because I was making ammonium nitrate from calcium nitrate via the ammonium carbonate route. While this works and it works
great, I realized I spent too much money on ammonium carbonate and the sodium bisulfate method would be cheaper overall (even considering the
additional stuff needed for added purification).
I have two questions, however, before I proceed.
1: There will be some sodium sulfate contamination (unless further purified) how would this affect things like nitrations or nitric acid making using
the ammonium nitrate as is? I assume the sulfate will not produce an adverse effect when added to sulfuric acid (aside from going back to bisulfate?),
so it won't interfere in nitrating something using the ammonium nitrate obtained this way. For nitric acid, the byproduct will always be ammonium
bisulfate regardless, so nothing to worry about? Am I right in this assumption?
2: I looked up the solubility of ammonium nitrate and sodium sulfate. It said that AN is 'soluble' in acetone, while sodium sulfate is not. No
information on how soluble it is, but would that mean it is much more soluble in acetone than it is in methanol? that would make it the superior
solvent. Any more information on its solubility in acetone? Ammonium nitrate that is.
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Precipitates
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1. Reduced yield and "messy" reactions - but depending on your objective might not affect the end product
2. Years ago I produced AN, and then purified it by dissolving in methanol. It dissolved well, albeit in copious methanol (probably around 500 ml for
between 50-80g AN). Although a copious amount of methanol was used for a relatively small amount of product, this can be recovered through
distillation, and the vast improvement in purity is worth it imo.
Inorganic salts tend to dissolve better in smaller molecular mass solvents, so its hard to see acetone being superior.
Researching further, from the following thread, AN was found to be poorly soluble in acetone:
Separation of Ammonium Nitrate and Potassium Chloride
http://www.sciencemadness.org/talk/viewthread.php?tid=17525
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Precipitates
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More detail on the solubility of ammonium nitrate in acetone, and a research paper with a solubility value of 0.145 g/100g solvent (1), can be found
on this more recent thread:
Identifying your calcium ammonium nitrate
https://www.sciencemadness.org/talk/viewthread.php?tid=15926...
(1) Spectra of Inorganic Nitrates in Acetone and the Use of Such Spectra in Analytical Chemistry
https://apps.dtic.mil/sti/pdfs/AD0673124.pdf
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MadHatter
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Ammonium Nitrate from CAN
My post from 2022:
https://www.sciencemadness.org/whisper/viewthread.php?tid=15...
11th post in thread. Have fun !
From opening of NCIS New Orleans - It goes a BOOM ! BOOM ! BOOM ! MUHAHAHAHAHAHAHA !
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fx-991ex
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Thats what i do too, $$CAN + (NH4)2SO4 \rightarrow NH4NO3 + CaSO4 + H2O$$
I usually let the CaSO4 decant over a night, remove top liquid and have the rest of the mass in a cofee filter and i press it by hand slowly.
Next time i will try in a syringe with a cotton or ill get filter aid celite/diatomaceous earth if i need a bigger batch.
Then i heat it to near saturation and get most of the remaining CaSO4 to precipitate/hot filter as its less soluble when hot(using the solubility
data).
For sodium nitrate i use NaHCO3. i heat to decompose the ammonium carbonate and make it saturated with the nitrate salt(again i use the solubility
data) then i hot filter the CaSO4.
Next time i will try KNO3 with KCl.
[Edited on 20-1-2024 by fx-991ex]
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MadHatter
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Calcium Sulfate
Barely soluble:
Most soluble: .265 g/100 ml @ 40 C.
Least soluble: .205 g/100 ml @ 100 C.
From opening of NCIS New Orleans - It goes a BOOM ! BOOM ! BOOM ! MUHAHAHAHAHAHAHA !
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ManyInterests
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Thanks, you used a ratio of 8 grams to 5 grams of CAN and ammonium sulfate respectively? I am sure it'll probably work just as well with regular
calcium nitrate.
Edit: I just want to make sure, using that ratio will result in negligible ammonium sulfate contamination? I am not worried about calcium sulfate
since that is easy to get rid of.
[Edited on 20-1-2024 by ManyInterests]
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fx-991ex
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| Quote: Originally posted by ManyInterests |
Thanks, you used a ratio of 8 grams to 5 grams of CAN and ammonium sulfate respectively? I am sure it'll probably work just as well with regular
calcium nitrate.
Edit: I just want to make sure, using that ratio will result in negligible ammonium sulfate contamination? I am not worried about calcium sulfate
since that is easy to get rid of.
[Edited on 20-1-2024 by ManyInterests] |
If your starting material is very pure(which is the case with mine surprisingly, or near the end just add the rest slowly till no more precipitate).
https://www.webqc.org/balance.php
(Ca(NO3)2)5NH4NO3(H2O)10 + (NH4)2SO4 = NH4NO3 + CaSO4 + H2O
8G CAN + 4.8912G (NH4)2SO4 = 6.5182G NH4NO3 + 5.0393G CaSO4 + 1.3337G H2O(some water will be used for the crystallization of the CaSO4 hydrates.)
[Edited on 20-1-2024 by fx-991ex]
[Edited on 20-1-2024 by fx-991ex]
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ManyInterests
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| Quote: Originally posted by fx-991ex | | Quote: Originally posted by ManyInterests |
Thanks, you used a ratio of 8 grams to 5 grams of CAN and ammonium sulfate respectively? I am sure it'll probably work just as well with regular
calcium nitrate.
Edit: I just want to make sure, using that ratio will result in negligible ammonium sulfate contamination? I am not worried about calcium sulfate
since that is easy to get rid of.
[Edited on 20-1-2024 by ManyInterests] |
If your starting material is very pure(which is the case with mine surprisingly, or near the end just add the rest slowly till no more precipitate).
https://www.webqc.org/balance.php
(Ca(NO3)2)5NH4NO3(H2O)10 + (NH4)2SO4 = NH4NO3 + CaSO4 + H2O
8G CAN + 4.8912G (NH4)2SO4 = 6.5182G NH4NO3 + 5.0393G CaSO4 + 1.3337G H2O(some water will be used for the crystallization of the CaSO4 hydrates.)
[Edited on 20-1-2024 by fx-991ex]
[Edited on 20-1-2024 by fx-991ex] |
Thanks. Like I said, at this point I am done with cold pack crap. I got me a bag of very pure calcium nitrate. I was expecting it to have anti-caking
agents... but no. When I dissolved it in an excess of water, it was so clear you'd think there was nothing dissolved in it. I used 2.5 liters to
dissolve 1.5kg of calcium nitrate, BTW.
I probably will need another bag, and it will be another pure calcium bag. Given the expense of ammonium carbonate, I am seriously just contemplating
getting the ammonium sulfate and using your method, if the end result is pure, or almost completely pure, ammonium nitrate (with negligible ammonium
sulfate contamination if I used an excess) then I will be satisfied.
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fx-991ex
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| Quote: Originally posted by ManyInterests |
Thanks. Like I said, at this point I am done with cold pack crap. I got me a bag of very pure calcium nitrate. I was expecting it to have anti-caking
agents... but no. When I dissolved it in an excess of water, it was so clear you'd think there was nothing dissolved in it. I used 2.5 liters to
dissolve 1.5kg of calcium nitrate, BTW.
I probably will need another bag, and it will be another pure calcium bag. Given the expense of ammonium carbonate, I am seriously just contemplating
getting the ammonium sulfate and using your method, if the end result is pure, or almost completely pure, ammonium nitrate (with negligible ammonium
sulfate contamination if I used an excess) then I will be satisfied. |
CAN fertilizer is very pure sometime, i got the MegaCrop 2 part B from amazon, its very pure, barely any dirt to filter, work with stochiometric
quantities.
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