Sciencemadness Discussion Board - Ammonium Nitrate from Calcium Ammonium Nitrate

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

Backyard Chemist - 30-12-2014 at 10:50

Ive tried my best, but I cant find anything on this matter...

blogfast25 - 30-12-2014 at 10:56

Here's one about NaNO3 from CAN.

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

blogfast25 - 30-12-2014 at 11:03

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 Ca2+ by the equivalent quantity of NH4+.

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]

Bert - 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

hissingnoise - 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]

Backyard Chemist - 30-12-2014 at 12:26

Yeah, I'm using a cold pack!

Backyard Chemist - 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..

blogfast25 - 31-12-2014 at 07:46

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]

hyfalcon - 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.

Xenoid - 31-12-2014 at 14:02

... 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.

DraconicAcid - 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.

macckone - 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.

AngelEyes - 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.

ManyInterests - 18-1-2024 at 19:33

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.

Precipitates - 18-1-2024 at 23:43

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

Precipitates - 19-1-2024 at 00:06

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

Ammonium Nitrate from CAN

MadHatter - 19-1-2024 at 17:01

My post from 2022:

https://www.sciencemadness.org/whisper/viewthread.php?tid=15...

11th post in thread. Have fun !

fx-991ex - 19-1-2024 at 17:41

My post from 2022:

https://www.sciencemadness.org/whisper/viewthread.php?tid=15...

11th post in thread. Have fun !

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]

Calcium Sulfate

MadHatter - 19-1-2024 at 21:54

Barely soluble:

Most soluble: .265 g/100 ml @ 40 C.
Least soluble: .205 g/100 ml @ 100 C.

ManyInterests - 20-1-2024 at 04:06

My post from 2022:

https://www.sciencemadness.org/whisper/viewthread.php?tid=15...

11th post in thread. Have fun !

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]

fx-991ex - 20-1-2024 at 06:13

My post from 2022:

https://www.sciencemadness.org/whisper/viewthread.php?tid=15...

11th post in thread. Have fun !

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]

ManyInterests - 20-1-2024 at 06:41

Quote: Originally posted by fx-991ex

My post from 2022:

https://www.sciencemadness.org/whisper/viewthread.php?tid=15...

11th post in thread. Have fun !

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.

fx-991ex - 20-1-2024 at 08:46

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.

ManyInterests - 20-1-2024 at 09:35

Quote: Originally posted by fx-991ex