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Author: Subject: Ammonium Nitrate from Calcium Ammonium Nitrate
Backyard Chemist
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[*] posted on 30-12-2014 at 00:50
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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[*] posted on 30-12-2014 at 06:15


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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[*] posted on 30-12-2014 at 10:50


Ive tried my best, but I cant find anything on this matter...
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[*] posted on 30-12-2014 at 10:56


Here's one about NaNO3 from CAN.

http://www.sciencemadness.org/talk/viewthread.php?tid=39612#...




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[*] posted on 30-12-2014 at 11:03


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.




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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[*] posted on 30-12-2014 at 11:23


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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[*] posted on 30-12-2014 at 12:19


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?

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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[*] posted on 30-12-2014 at 12:26


Yeah, I'm using a cold pack!
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[*] posted on 30-12-2014 at 12:27


But it is possible, I've heard, to isolate the ammonium nitrate from the CAN by boiling at filtering..
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[*] posted on 31-12-2014 at 07:46


Quote: Originally posted by Backyard Chemist  
But it is possible, I've heard, to isolate the ammonium nitrate from the CAN by boiling at filtering..


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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[*] posted on 31-12-2014 at 12:26


Use ammonium sulfate to displace the calcium ion. It's hard to stop at the right point in the addition.
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[*] posted on 31-12-2014 at 14:02


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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[*] posted on 31-12-2014 at 15:17


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.



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[*] posted on 23-6-2021 at 10:09


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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[*] posted on 24-6-2021 at 06:53


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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