Sciencemadness Discussion Board

ammonium nitrate from calcium-ammonium nitrate cold packs?

ManyInterests - 20-6-2022 at 08:08

This topic has been brought up previously (and I even have another thread on my troubles) but I figured this would warrant it's own thread since I only heard of this method recently from Synthesizer.

When making nitrate salts from CAN cold packs, I know (and have done many times) of adding potassium chloride to a filtered CAN solution (removing the filler, of course) will result in potassium nitrate precipitating. This is something I have done many, many times before and I know it works. Sodium nitrate can be made also with adding sodium bicarbonate to the solution, or sodium hydroxide (which will generate ammonia gas and must be done in a well ventilalted area) and the resulting mixture can be boiled down to make sodium nitrate.

For getting pure ammonium nitrate, however, I heard that using ammonia water (even 6% household solution will work I heard) to the CAN will cause ammonium nitrate to precipitate? Is this correct?

I want to have some idea on how to do this properly. When I make potassium nitrate from cold packs, I first add 250ml of distilled water to 210 grams of CAN prills (this proportion never changes), heat it up, and then filter out the insoluble filler.

Would I do the same thing, but instead of distilled water I just add the ammonia? and after which I just let it chill nice and slow to get my ammonium nitrate or do I need to boil the stuff down further after filtration?

Boiling down

MadHatter - 20-6-2022 at 17:34

It's very likely you'll have to boil down or evaporate to get the NH4NO3 because
118 grams of this will dissolve in 100ml water at freezing. My preferred method
is react the CAN with (NH4)2SO4, generally available from the same places that
supply CAN, filter out the CaSO4(pain in the ass I know) then evaporate.

B(a)P - 20-6-2022 at 18:55

Quote: Originally posted by ManyInterests  

For getting pure ammonium nitrate, however, I heard that using ammonia water (even 6% household solution will work I heard) to the CAN will cause ammonium nitrate to precipitate? Is this correct?

I want to have some idea on how to do this properly. When I make potassium nitrate from cold packs, I first add 250ml of distilled water to 210 grams of CAN prills (this proportion never changes), heat it up, and then filter out the insoluble filler.

Would I do the same thing, but instead of distilled water I just add the ammonia? and after which I just let it chill nice and slow to get my ammonium nitrate or do I need to boil the stuff down further after filtration?


This is an interesting idea. It may be that ammonium nitrate is less soluble at a higher pH or it could be a common ion effect.
I see a problem though, I would have expected introducing ammonium hydroxide to a solution of CAN would cause calcium hydroxide to precipitate.

ManyInterests - 21-6-2022 at 12:15

Quote:
This is an interesting idea. It may be that ammonium nitrate is less soluble at a higher pH or it could be a common ion effect.
I see a problem though, I would have expected introducing ammonium hydroxide to a solution of CAN would cause calcium hydroxide to precipitate.


Yep, I am working with that with synthesizer. I haven't started this experiment just yet, as right now I am trying to turn sodium chlorate into perchlorate via heat decomposition... I am not getting super good results.

It is either that I added too much chlorate to the crucible and it isn't heating up enough. I am not insulating my crucible sufficiently. Or my stovetop just isn't getting hot enough.

B(a)P - 21-6-2022 at 15:41

Have you considered using ammonium sulfate? It might take some experimentation to get the amount of ammonium sulfate right, as presumably you don't know the ratio of calcium nitrate to ammonium nitrate in your product? Someone on the forum might know what ratio to expect.
Calcium nitrate is much more soluble in ethanol than ammonium nitrate so that may also be a route worth considering.

ManyInterests - 21-6-2022 at 15:59

I didn't think about using ammonium sulfate. No.

BTW, I do have some ammonium chloride right now. Would that work?

Edit: I am also trying to make sodium perchlorate as I write this. I had a crucible on my stovetop for 6 hours (3 hours without aluminum wrapping, and another 3 with a total aluminum covering). I saw a color change, but the chlorate I put in did not melt. It was definitely over 200 C. Maybe 300 (but I cannot confirm).

The chlorate changed color as I said, would I have some perchlorate in it? Or was my attempt a dud?

[Edited on 22-6-2022 by ManyInterests]

B(a)P - 21-6-2022 at 16:32

Quote: Originally posted by ManyInterests  
I didn't think about using ammonium sulfate. No.

BTW, I do have some ammonium chloride right now. Would that work?

[Edited on 22-6-2022 by ManyInterests]


You are trying to remove the calcium cation by introducing an anion that forms a water insoluble (or at least poorly soluble) solid with it. Calcium chloride is quite water soluble, though its solubility curve is much flatter than ammonium nitrate. Ordinarily you could make use of this, but because ammonium nitrate is so water soluble by the time you boil down the solution sufficiently to remove enough calcium chloride, the solution will just turn into a solid mass on cooling trapping the residual calcium chloride. Calcium chloride, like ammonium nitrate, is soluble in alcohols, so you may be able to recrystallise some relatively pure ammonium nitrate, you would have to try it out.


Quote: Originally posted by ManyInterests  


Edit: I am also trying to make sodium perchlorate as I write this. I had a crucible on my stovetop for 6 hours (3 hours without aluminum wrapping, and another 3 with a total aluminum covering). I saw a color change, but the chlorate I put in did not melt. It was definitely over 200 C. Maybe 300 (but I cannot confirm).

The chlorate changed color as I said, would I have some perchlorate in it? Or was my attempt a dud?

[Edited on 22-6-2022 by ManyInterests]


For this to work the sodium chlorate needs to be held at a temperature in excess of 300C for a period of time. Sodium chlorate melts at around 250 to 260 C. During this process you should see the sodium chlorate melt and then start bubbling as it looses oxygen. When it stops bubbling the reaction has gone to completion. As you say, your sodium chlorate did not get hot enough to melt, so it did not get above 250 C, so no reaction has occurred. A change in colour is not a good indicator as both sodium chlorate and perchlorate are white in colour. The change in colour is likely related to impurities in your chlorate. You might be better to use a propane torch as a heat source they are readily available at hardware stores or kitchenware stores, at least they are here.

ManyInterests - 21-6-2022 at 16:59

More challenges. It reminds me of the troubles I had in making nitric acid... but I succeeded then, so I hope to succeed after struggling with this.
Quote:
You are trying to remove the calcium cation by introducing an anion that forms a water insoluble (or at least poorly soluble) solid with it. Calcium chloride is quite water soluble, though its solubility curve is much flatter than ammonium nitrate. Ordinarily you could make use of this, but because ammonium nitrate is so water soluble by the time you boil down the solution sufficiently to remove enough calcium chloride, the solution will just turn into a solid mass on cooling trapping the residual calcium chloride. Calcium chloride, like ammonium nitrate, is soluble in alcohols, so you may be able to recrystallise some relatively pure ammonium nitrate, you would have to try it out.


If that is the case, then I might try with the ammonia water for now... if that doesn't work I'll have to wait for the final failsafe... using ammonia and nitric acid. Which will work and is much easier than anything else.
Quote:
For this to work the sodium chlorate needs to be held at a temperature in excess of 300C for a period of time. Sodium chlorate melts at around 250 to 260 C. During this process you should see the sodium chlorate melt and then start bubbling as it looses oxygen. When it stops bubbling the reaction has gone to completion. As you say, your sodium chlorate did not get hot enough to melt, so it did not get above 250 C, so no reaction has occurred. A change in colour is not a good indicator as both sodium chlorate and perchlorate are white in colour. The change in colour is likely related to impurities in your chlorate. You might be better to use a propane torch as a heat source they are readily available at hardware stores or kitchenware stores, at least they are here.


I used part to my first batch of chlorate. It did have a tint possibly from rust falling into the liquid. My second batches were much more pure (and pure white). I had two sub-batches in my second batch. one of them appears to have some sodium chloride, while the other was is quite pure, given how powerfully and quickly it burned when I gave it the burn test.

I think my next attempt will be better, and I will not put in 60 grams, I will put no more than 20. I don't know how hot it got, but it was definitely over 200 C but the stuff didn't melt.

I really need to see some positive results soon. It's getting depressing working so hard over the past week only to get dud after dud...

B(a)P - 21-6-2022 at 17:51

Quote: Originally posted by ManyInterests  


I think my next attempt will be better, and I will not put in 60 grams, I will put no more than 20. I don't know how hot it got, but it was definitely over 200 C but the stuff didn't melt.

I really need to see some positive results soon. It's getting depressing working so hard over the past week only to get dud after dud...


As long as you learn something from your from your failures then you should look at them in a positive light.

So why do you think your next attempt will be better? Are you trying a new heat source or do you think the reduced thermal mass will be sufficient? If you are not using a different heat source then I don't see how this is going to work. In your previous attempt you did not manage to get to 250 C and for the reaction to occur you need more than 300 C, reducing the thermal mass by 40 g is unlikely to achieve this. While a stove top coil should get to 500 C you are unlikely to transfer much of this to your crucible because of its size, the amount of direct contact and the relatively poor heat conductance compared to metal, which the stovetop is designed for. Because you are not transferring much heat the coil quickly gets to about 500 C then turns off until it cools sufficiently to switch back on. Using a flame you can apply heat full time allowing your crucible to get to the temperature you need it to be.

ManyInterests - 21-6-2022 at 18:20

If that is the case, I will look into getting a butane torch. I did have some people suggest that I put a plant pot on top of my crucible in order to make it hotter on my stove top.

Laboratory of Liptakov also had two ways: One involving a heat gun, the other involving a butane torch. Both, however, showed him putting the crucible in a cinder block that also acted to both insulate it further AND to give a place to concentrate the heat towards the crucible.

I will try to find something like that. I did promise LL, mineman, and maybe another person that I will make CHP. I am only missing ammonium perchlorate to make CHP right now, and to get some of that, I need sodium perchlorate.

Edit: The reason why I thought putting less might work is because maybe my crucible was getting hot enough? But not for the amount I put in it?

Edit2: While I go shopping for the time being and searching. I did decide to put some of my purest sodium chlorate (10 grams) into my curcible and put it in my oven instead at max power. I am aware that it doesn't go beyond 260 C, but it's worth a shot.

[Edited on 22-6-2022 by ManyInterests]



[Edited on 22-6-2022 by ManyInterests]

ManyInterests - 22-6-2022 at 07:34

BTW, about the ammonium nitrate experiement I attempted? I am not sure if it worked. The solid cake that formed after I dried everything off looks more like calcium than ammonium nitrate (greyish color).

If there is one thing I will try to do, however, is see if I can use those cold packs I got to make potassium or sodium nitrate. If they contained CAN and not real ammonium nitrate that should be possible. I made potassium nitrate a million times before without a hitch.

Ammonium Nitrate from CAN

MadHatter - 22-6-2022 at 10:35

Method for production using ammonium sulphate.

Previous thread(11th post in thread): http://www.sciencemadness.org/talk/viewthread.php?tid=154741...

ManyInterests - 22-6-2022 at 14:10

I think I will put my ammonium nitrate search on hold for now. Since I am looking for a way to convert my sodium chlorate into perchlorate.
Quote:
So why do you think your next attempt will be better? Are you trying a new heat source or do you think the reduced thermal mass will be sufficient? If you are not using a different heat source then I don't see how this is going to work. In your previous attempt you did not manage to get to 250 C and for the reaction to occur you need more than 300 C, reducing the thermal mass by 40 g is unlikely to achieve this. While a stove top coil should get to 500 C you are unlikely to transfer much of this to your crucible because of its size, the amount of direct contact and the relatively poor heat conductance compared to metal, which the stovetop is designed for. Because you are not transferring much heat the coil quickly gets to about 500 C then turns off until it cools sufficiently to switch back on. Using a flame you can apply heat full time allowing your crucible to get to the temperature you need it to be.


Would this torch do? I went to a local hardware store and I saw it on sale. I am not sure if it'll get hot enough, but I hope it does. I haven't bought it yet since I want to make one last attempt at making perchlorate on my stovetop (using a clay pot for added insulation).

The sales people didn't know how hot the torch got. But I want to know... how would the setup look like? Laboratory of Liptakov uses a cinder block for added insulation, but I saw ChemPlayer's video where he did it over a simple open flame (from a gas stove, but hat's something else).

Do I just put it on the concrete floor of my balcony and secure everything in place and light it up? Or do I need to make something more elaborate?

Also do you have experience with 14.1 oz propane tanks? How long do they last when left on full power?

Torch3.jpg - 2.3MBTorch4.jpg - 2.3MB

B(a)P - 22-6-2022 at 15:07

That will work well. The flame temperature will be nearly 2000 C.
Ideally you would use a retort stand, ring and clay pipe triangle that you can sit your crucible in, but I am guessing you do not have these items?
The torch can sit on the floor, you just need to have something that can hold the crucible that is stable and heat resistant and allows the flame to be in contact with the crucible.
If you had some sturdy steel wire or rod you could make a loop with that.
If you had some coarse mesh or a bbq grill you could stand that between two bricks of the right height.
This is what you are trying to achieve.
image sourced from https://chemistry.stackexchange.com/questions/31504/crucible...


781kB.jpeg - 30kB

Edit
I should have said, best do this in a well ventilated space. Also these types of torches burn at around 2oz propane /h at the highest setting.

[Edited on 22-6-2022 by B(a)P]

ManyInterests - 22-6-2022 at 17:18

I can get steel wire or BBQ grills really cheap at a dollar store. I can make the setup for this. Right now the weather is really windy and I would need to wait for things to calm down before trying to build a stable setup.

Also that retort ring is something I did have before, but I will need to get it back before I can do something like that. So building a BBQ type platform is my best bet now.

Thanks for telling me about the burn rate. If it only burns 2 oz per hour, I can make good perchlorates this year. If it is as hot as you say it is, it probably don't need more than one hour to thermally decompose 60 grams of the stuff.

Edit: I don't think the plant pot method worked. So off I got to buy that propane torch.

[Edited on 23-6-2022 by ManyInterests]

ManyInterests - 24-1-2023 at 21:47

Quote: Originally posted by MadHatter  
It's very likely you'll have to boil down or evaporate to get the NH4NO3 because
118 grams of this will dissolve in 100ml water at freezing. My preferred method
is react the CAN with (NH4)2SO4, generally available from the same places that
supply CAN, filter out the CaSO4(pain in the ass I know) then evaporate.


Well I decided to resurrect this thread because I now do have ammonium sulfate to use. Any information on the stoichiometric amounts of CAN and ammonium sulfate?

Also if I can draw attention to my other thread because I am having some troubles making pure sodium nitrate...