Sciencemadness Discussion Board - calcium nitrate to ammonium nitrate

calcium nitrate to ammonium nitrate

fatkangaroo - 30-12-2004 at 00:48

Looking for some help to do this reaction properly as I cant seem to get it right.
As I understand it the CN is dissolved into boiling water and the calcuim drops out as it won't dissolve in water.
Well I gave it a shot and the problem is everything dissolves and there are no solids to filter off. I boiled for ten minutes or so then put it in the frezzer. Nothing is coming out full stop.
Any help would be appreciated.

cyclonite4 - 30-12-2004 at 04:27

Problems with that method:
1. Ca(NO3)2 is quite soluble in water.
2. The Calcium wont just 'drop' out for no reason.
3. You lack the ammonium ion in all of your procedure.

What you should try is mixing with a stoichiometric amount of NH4OH with the Ca(NO3)2 to precipitate out Ca(OH)2, filter it off, and you will be left with a NH4NO3 solution.

Jome - 30-12-2004 at 07:02

That wont work either, ammonia is a base, but it is to weak to push Ca(OH)2 out of solution.

I tried it two months ago, and not even one tenth of calculated ammount Ca(OH)2 precipated.
To push Ca(OH)2 out of a solution of Ca-nitrate the base has to be stronger, it works fine with NaOH or KOH which I've used dozens of times.

cyclonite4 - 30-12-2004 at 07:38

Quote:

Originally posted by Jome
That wont work either, ammonia is a base, but it is to weak to push Ca(OH)2 out of solution.

I tried it two months ago, and not even one tenth of calculated ammount Ca(OH)2 precipated.
To push Ca(OH)2 out of a solution of Ca-nitrate the base has to be stronger, it works fine with NaOH or KOH which I've used dozens of times.

I know. But with your method your not really forming AN are you now?

Maybe try precipitating a less soluble calcium compound?

[Edited on 30-12-2004 by cyclonite4]

hodges - 30-12-2004 at 16:04

How about mixing the calcium nitrate solution with ammonium sulfate? Calcium sulfate is insoluable so will precipitate out, leaving ammonium nitrate solution.

guy - 31-12-2004 at 16:25

You can also mix regular ammonia with calcium nitrate to precipitate Ca(OH)2 and you end up with AN. Simple.

Hodges way should work fine

FloridaAlchemist - 31-12-2004 at 19:24

Calcium Nitrate and Ammonium Sulfate should work fine... The Calcium Sulfate is filtered off and the water is evaporated from the Ammonium Nitrate solution at approx 105 'C in a oven. :cool:

fatkangaroo - 31-12-2004 at 22:45

Thanks everyone for your comments and assistance.
Just a little unsure how much of the Ammomium Sulfate should be added to the Calcium Nitrate solution?
I was wondering the same thing about the Ammonia-Calcium Nitrate technique.
I attemped adding the NaOH to the very cold solution that I still had from my first attempt. Nothing happened that I saw, but didnt really give it a chance. I dumped it after about 1 hour.

runlabrun - 1-1-2005 at 06:07

Amounts of each reactant depends on the ratio:
Ca(NO3)2 + (NH4)2SO4 --> NH4NO3 + CaSO4
Equimolar amounts. Got it?

What do you mean about " was wondering the same thing about the Ammonia-Calcium Nitrate technique." You want to know how to go in the reverse direction of what you have just done? ie Ammonium Nitrate --> Calcium Nitrate?

Adding NaOH to ammonium nitrate would have given you a solution of Sodium nitrate and ammonia in water solution.
You wouldnt have seen anything because both Ammonium and Sodium nitrates are soluble in water so the reaction would go unseen.

Best to mix a calcium compound of a weaker anion, the stronger Ca will attract the stronger anion (nitrate).
Acetate? You would do this:

NH4NO3 + Ca(C2H3O2)2 --> Ca(NO3)2 + NH4(C2H3O2)

-rlr

fatkangaroo - 1-1-2005 at 14:04

OK I am going to try the Calcuim Nitrate Ammonium Sulfate route and see how I go. What I really want to know is how much of the Ammonium Sulfate shound be added per 100 grams of Calcuim Nitrate.
I am very new to Chemistry so I don't know how to work these things out for my self.
I am learning though and having lots of fun and the same time.Makes me wish I tried a bit harder at school,I am a late bloomer you see. My chemisty adventure has only just begun and I feel so far behind the 8-ball compaired to everyone else on these boards.So please understand I am a bit slow on the uptake.My lab is the poor mans kind-spagetti jars pyrex bowls and hotplate basic chemicals from open sources hardware ect.

Magpie - 1-1-2005 at 14:25

You are on the right track I believe. Calcium sulfate is insoluble and should precipitate out. You can then decant or filter off the ammonium nitrate solution. But if you don't get the stoichiometry right you will have ammonium sulfate or calcium nitrate in your product as contaminant.

Write a balanced chemical reaction. Determine your molecular weights. Multiply the molecular weights times the corresponding coefficients in the reaction. The results will allow you to calculate the weight of ammonium sulftate needed per gram (or kg) of calcium nitrate used. If you don't understand any of this go to your public library and check out a text on elementary chemistry. Let us know how this works out. Where do you get the calcium nitrate and ammonium sulfate? - fertilizers?

fatkangaroo - 2-1-2005 at 12:52

Ahhh. I see... fun fun fun.
Yes indeed my Cacium Nitrate and Ammonium Sulfate are both fertilizers.
Found the molecular weights, just doing a online stoichiometry lesson at the moment. I know it will take me some time to fully understand all the concepts.I have really have to get my own books.Downloaded Vogels but I find it very hard to read as the writting is very small and faded.
I think for today I will give it a try without knowing the bananced reaction.
The plan is to make the hot Calcuim Nitrate solution then slowly add the Ammonium Sulfate spoonful by spoonfull untill I see the Calcuim Sulfate appear and take it from there.

neutrino - 2-1-2005 at 14:21

Don’t you mean add sulfate until CaSO4 stops precipitating? You really should go with accurately weighed masses, though.

runlabrun - 2-1-2005 at 19:42

Yeah neutrino is right, you should add till it stops precipitating. But accuracy with amounts is advisiable, you dont want to end up with an excess of the equally soluble ammonium sulphate in your solution.

You should come up with 80.6g Ammonium sulphate to treat 100g of Calcium Nitrate.

Make the solution of 100g calcium nitrate in just enough water (138g Calcium nitrate is soluble in 100mL of water) to dissolve the solid so this means around about 72.5mL. Slowly add the 80.6g ammonium sulphate in small portions stirring in between each addition. You will see calcium sulphate precipitating out, being 0.21g per 100mL it isnt very soluble at all. Filter out the precipitate and collect the fluid, this is your ammonium nitrate in solution.

Sound good? Easy?

-rlr

fatkangaroo - 3-1-2005 at 11:52

Happy days :cool:

I really feel indebted to you guys!
For me the success of this experiment will be a major steping stone and I feel good.Can't wait to get started.
Thanks runlabrun for spelling it out for me clear and simple.
Still going to hit the books and learn to work things out for myself and hopefully be able to contribute to the board and one day be able to help someone else.
Let you know tommorow how things went.

fatkangaroo - 3-1-2005 at 19:50

Just finished trying to make the Ammonium Nitrate and had no luck, hoping for another point in the right direction.
First I added 100 grams of Calcuim Nitrate to 75ml of distilled boiling water this all dissoved quickly and the mix started to get cloudy.Next I added the 80 grams of Ammonium Sulfate slowly over around 20 minutes and the mix looked like milk.I was a little confused at this point as I could not tell what was the Calcuim Sulfate precipitating and what was undissolved Ammonium Sulfate.Anyway the mix was very thick and filtering came next.A large amount of chalky stuff was collected and thrown away. I put half the solution into the frezzer and so far nothing has happened. The other half of solution was put into the oven at 105 'c. It boiled down into a brown sludge

which looked nothing like beautiful crystals I was hoping for.
Any suggestions?

runlabrun - 3-1-2005 at 20:56

The mix started to get cloudy when it was just calcium nitrate in water? Maybe i was a little off on the solubility could try to add a bit more water, 20-30mL or so.

Your mix after the addition of ammonium sulphate looked like milk, that should be good, CaSO4 is a white precipitate, leaving the mixture to settle and cool (place it in the fridge) should allow you to achieve a white sediment.

Very thick? Example? It would be thick while the water is still hot and the precipitate is floating around, allow to form a sediment as mentioned above.

Chalky filtrate would be the calcium sulphate and any undissolved crap. Putting the fluid into the freezer wont do much as ammonium nitrate is very soluble (208g per 100mL 25oC water) so you wont see anything.

However i am interested in your brown sludge.... no idea what that would be.... maybe some contaminants in your original reagents.... where were they from? The reaction would work with some gentle heating and quality reagents.
The product may have contamination so re-x from alcohol to see if you can leave some of the crap behind.

-rlr

neutrino - 4-1-2005 at 03:19

A word of advice: whenever you’re going to do a precipitation reaction like this which produces large amounts of precipitate, add a very large excess of water unless you want a large gel-like cake of precipitate.

brown sludge

Magpie - 4-1-2005 at 10:02

You should not have any precipitate until you start adding the ammonium sulfate. If you do you didn't have enough water initially.

There should be no need for heating or freezing.

Remember that you are working with fertilizer grade not reagent grade material. There's a reason why the former is cheap and the latter is expensive - i.e., purity. That doesn't mean you can't eventually purify your ammonium nitrate with proper procedures, however. Your sludge is probably most ammonium nitrate.

guy - 4-1-2005 at 14:48

The brown sludge is probably partially hydrated calcium sulfate known as Paster of Paris.

neutrino - 4-1-2005 at 16:09

Plaster would be a white gel-ish precipitate. Come to think of it, I do remember a small amount of brown goo when I was boiling down ammonium nitrate from cold packs. Might it be a decomposition product of some sort?

The_Davster - 4-1-2005 at 17:26

Maybe the decomposition product of some additive... The decomposition products of ammonium nitrate are all gaseous.

runlabrun - 4-1-2005 at 17:55

"Yes indeed my Cacium Nitrate and Ammonium Sulfate are both fertilizers. " -fatkangaroo

I think this is the problem, depending on what % CN and AS are in the mix and what else is there....
Sorry bout the water volume issue, i thought the mix would sediment rather easily in the fridge, obviously it was incorrect, so as neutrino said, use large volume of water.
What has been assumed is all i can think of, purification of starting materials would be my best idea for a resolution to the problems your having.

-rlr

[Edited on 5-1-2005 by runlabrun]

fatkangaroo - 4-1-2005 at 18:15

If first you don't suceed try try again.
Gave It another try after reading your comments and doing a bit searching around for answers.
I followed the same procedure as last time accept I used 150ml of boiling water.The hot solution got very thick and I filtered it quickly. This is because as soon as stirring is stopped it thickens immediatly even if the solution is cooled,and not just thick its just about a solid.Anyhow I put the soultion into fridge and with in 10 minutes there was another layer of chalk to filter off. Once that was done I was left with a clear water looking solution

This time I put the solution on a hot water bath and slowly evapourated and water out. To my absolute joy small white crystals started forming and a couple of long needle like ones to.

As for the brown sludge from yesterday, I started looking for some answers. I found a archived thread from another board. The thought there was AN when heated in solution can go straight from the liquid to molten AN without you knowing it.I think now this may have happened to me.I put a small sample into water and it got cold like AN should do. Now I have to find the best solvent to recrystallize in.
So all in all I am pretty happy the way things are going although I'm not 100% sure what I have is AN. I have plenty of Calcium Nitrate and Ammonium Sulfate so I'm just going to keep on going to I get it as perfect as I can get it.

fatkangaroo - 5-1-2005 at 18:22

Just finshed another few batches.
I can say that the amount of water does not seem to have any influence on the mix. Large or small, the mix will still turn thick.
I use old sheets for filters and everytime I filter this mix it clogs up in seconds and the solution has to be squeezed out drop by drop.
I bought a instant cold pack to do some comparisions between the homemade stuff the commercial product. The main difference is the homemade product will not turn to crystals in the freezer while the ice pack AN loves it. Why is that? Also the shapes of the crystals vary greatly. I mean the cold pack AN forms beauitiful long clear needles, while the homemade gets tiny little white ones with the odd big one.
I have tried a few different ways of precipitating the homemade AN. Tried the oven again, this time on 75'c this mix is still going even now. It has been in there for around 25 mins there is a crystal like skin forming on the surface with a few crystals stuck to the sides and bottom. Next I tried the electric fry pan set on 110'c. Unfortunatlely it went molten. I was watching it wondering when it was going to happen. So I dumped what was left (not much) onto a dinner plate. The second the hot solution hit the plate it turned into a solid that ran all over the plate and left what looked like icing suger. Did again on the electric fry pan and let it boil right down then turned the heat off(molten again). As it cooled it formed a thin cake across the pan. This was a major pain to get off, got it done but scratched the crap out of the pan.The AN was very dirty from the cooking surface of the pan.
Any thoughts on what I could do to make this process more effective or anything you can see that Im doing wrong.
Just pulled the latest batch that was in the oven on 75'C. This is the best temperature for me. No molten crap straight to white powder with a 50 gram yield. Is this good or bad?

[Edited on 6-1-2005 by fatkangaroo]

Magpie - 5-1-2005 at 21:15

Just a few thoughts:

1. Can you just let the calcium sulfate settle to the bottom of the vessel (it may take a few hours) then decant off a fairly clear ammonium nitrate solution? This would save you from that messy filtration.

2. Evaporate the supernate at as high a temperature as practical until you just see signs of crystals in the body of the liquid. Then add a little boiling water to bring back to full dissolution.

3. Then let it cool undisturbed to room temperature on its own. Don't try to rush the crystallization - that leads to fine crystals. Try letting the supernate set at room temperature for a few hours before putting it in the refrigerator.

4. Impurities may be screwing up your crystal formation. I don't have any quick ideas for solving that problem.

I'm really not an expert at this. These are just some things I learned in organic lab. You should get some fundamental information like the solubility curve of ammonium nitrate in water vs temperature. This may help you understand the crystallization process.

If you are saying that your cold pack is pure ammonium nitrate in water and it is behaving much differently then you may indeed be fighting impurities. They may even be coming in through your water supply.

Try everything on a small scale until you get a good procedure.

runlabrun - 5-1-2005 at 21:40

Fatkangaroo:
50g NH4NO3 from how much Ca(NO3)2?
The difference in x-tal size would be purity, your homemade ones are not as pure as the cold pack ones... re-x from distilled water several times will clear up some of the insoluble impurities. Then you may get some bigger x-tals.

Magpie:
Sedimentation would take a long time, speed up by cooling in the fridge but still there would be alot of CaSO4 in suspension, especially with the large amount of precipitate filtration is a must.
The point about leaving it at room temp is also valid for large x-tal formation, the slower the solution cools the larger the x-tals will be.

-rlr

[Edited on 6-1-2005 by runlabrun]

Centimeter - 5-1-2005 at 22:35

You're not adding nearly enough water! You want A LOT of water in order to allow for a complete reaction. If it is getting as thick as you say it is, the chems are definately not interacting very well. You want there to be more than enough water for the calcium sulfate to settle out. The calcium sulfate that is formed from the precipitation is most definately going to be extremely fine...meaning you would have to use real filter paper (the slow stuff) to seperate it out. Don't try to use stoich to determine the amount of ammonium sulfate to add. Calcium nitrate is extremely hydroscopic and you can bet that your observed masses are greatly off. Furthermore, most calcium nitrate fertilizers are a mix of ammonium nitrate and calcium nitrate. I would recomend doing a sort of titration to determine the proper amount of ammonium sulfate. Make a solution of amonium sulfate with known molarity and slowly add it to a solution of the calcium nitrate. Once you see that no more precipitate is forming, you have your mass ratio! This ratio can be aplied to all future synthesis as the conditions should not change too dramatically. To purify the AN, you would have to play around with various solvents. May I ask what you plan on using this AN for? It doesn't sound like it is for chemistry reasons or you would just use the stuff from cold packs. If this is for explosives, I would highly recomend just using the calcium nitrate fertilizer as is. If you insist on using ammonium nitrate, it doesn't have to be all that pure.

fatkangaroo - 5-1-2005 at 22:43

runlabrun, I am using your formula every time-100 grams CN 80 gram AS and different amounts of water everytime-from this a got 50 grams AN. It is always around the 50 gram mark although the last one from the oven was the only one I weighed. I used the other stuff for various little tests and playing around with it trying to find out if the substance was AN.
As for information on crystal size and shape I only could find this from Urbanski.
Physical Properties.
Ammonium nitrate exists in the form of crystals, melting at 169.6'C. It occurs under five crystalline modifications distinguished by the transition temperatures.
Tetragonal -18 - 32.1'C----Orthorhombic +32.1'C - 84.2'C---Orthorhombic 84.2'C--- Cubic 125.2'C -169.6'C---Liquid.
And on solubility from the same text.
20'C - 66.1% solubility
40'C - 73.3%
60'C - 80.2%
80'C - 85.9%
100'C - 91.0%
120'C - 94.7%
140'C - 97.4%
160'C-99.4%
Unfortunately for me 95% of that text goes straight over my head but I read it anyway just on the hope I can find the break Im after.
After reading your suggestions and hints I pretty much agree with what you have said. Probably the best thing I can to is filter off and remove as much of the impurities as possible. This text also goes to say AN is soluble in methyl alcohol and ethyl alcohol. So tommorow I will buy a litre of metho and try dissolving the AN into it and see if some of the junk stays back.
Thanks for you input Centimeter and runlabrun & Magpie. I will have to get some bigger jars for all that water by the sound of it. I dont know the first thing about titration so I will have to look into it.

[Edited on 6-1-2005 by fatkangaroo]

[Edited on 6-1-2005 by fatkangaroo]

runlabrun - 6-1-2005 at 02:32

Metho is ethyl alcohol that has been denatured with stuff so people cant (or dont want to) drink it... around here we have small amouts of methyl alcohol and methyl iso-butyl ketone, however it is 95% ethyl alcohol....

However re-x of product in ethanol will not work.... calcium nitrate and calcium sulphate are both soluble in this solvent... you need to use water, ice cold water to be specific... this way you wont be dissolving the contamination as well as the product, hence your re-x will work to increase purity....

-rlr

fatkangaroo - 6-1-2005 at 17:21

Taking the hint from Centimetre I added the AS to the boiling water. I scaled back the amounts to 25 grams CN and 20 grams AS. After a little stirring the AS was fully dissolved and the water cloudy. Thinking that maybe the CN had taken in water it was put in the oven. The melting point is 45'C so its very easy to melt which a did a couple of times.Dried it properly and added the CN to the water AS mix. As usual the mix got a milky colour but stayed thin. For the first time I had a nice thin solution with a very fine precipitate everything was moving around and no solid gel anywhere to been seen. Gave it a good ten minute stir and put it into the fridge. 20 minutes later the precipitate had settled still nice and thin with a inch water layer on top.

I filtered using three slices of sheet not just one and for once it went perfectly no blockage no need for a another filtering as it came out like water. I put the solution in the fridge and that is where it still is.I can hardly believe the difference between doing the exact same thing but in a different order. But then again it may have been water levels all along? So I will do this a few more times yet.
On a side note I bought some methylated spirits - 96% ethanol to dissolve my other molten AN in. So I put 25 grams in a jar covered in 5 times the amount of metho gave it a good shake and it got cloudy most would not dissolve? Put 25 grams in another jar but put water in it whole lot dissolved clear in seconds? Dont know whats happening there.
Just dried the latest batch that is the 25CN 20AS and got 22 grams of white stuff with a pink tinge back. I have since found out metho is crap compaired to water for AN dissolving. I put the pure stuff from a cold back into metho even it would not dissove fully even after shaking it for half an hour.

[Edited on 7-1-2005 by fatkangaroo]

runlabrun - 9-1-2005 at 16:27

well the reason for its insoluble nature is unknown.... NH4NO3 and CaSO4 are both alcohol soluble according to msds documents. The extent to which they are soluble or the temperature at which the solubility occurs to a great extent may be the source of the problem, alcohols frequently have a sharp curve on a solubility vs temperature graph whereas the same graph for water is usually more linear.

Look up msds documents to find the solubility in various organic solvents not just water.

You may need to heat the metho to overcome the solubility curve problem. However if you want to re-x to purify your ammonium nitrate ie remove the remaining calcium sulphate i still say ice cold water as your solvent.
CaSO4 is only slightly soluble 0.21g/100g H2O at 25oC! so at 0oC where ice water is your CaSO4 will certainly precipitate, after a few runs your AN will be pure enough to use in whatever your making it for.

If you try and use heated metho to dissolve the impure AN you will also dissolve CS and this would devoid the proceedure of any benificial outcome other than getting the product with its impurities into solution of a common solvent.....

clear?
-rlr

fatkangaroo - 9-1-2005 at 20:07

:cool:

Happy days are here! Everything is working perfectly. It all seems so simple now.

The reason my homemade AN did not crystalize before was I had to much water in the solution. Even the cold pack AN will not crystalize out if to much water is present. That is the longest part of this procedure - removing all that water. But thats nothing I am just happy to have this procedure down pat. What a valuable lesson it has been. Keep in mind this was the first procedure I have ever done.
Extra thanks to runlabrun your help has been invalueble.

Ca nitrate as An repalcement for anfo?

pjig - 26-5-2010 at 14:36

Is this what your saying Centimeter ?

Quote:

If this is for explosives, I would highly recomend just using the calcium nitrate fertilizer as is. If you insist on using ammonium nitrate, it doesn't have to be all that pure.

Is this even possible with the Cn 15.5-0-0 +19% calcium
only having 1% as an ammonium salt?
Im sure your referring to the CAN nitrate not the CN.... I believe CAN has around 10% or so AN in it.. Making it a weak replacement for 34% AN.

This was a study done on which nitrates had an ability to detonate with a fuel mix.

Quote:

At the 250 pound scale, in the standard test protocol suggested by the NRC to identify detonable materials, there is no evidence that any of the single nitrate salts [Ca(NO3)2, KNO3, or NaNO3] were detonable with added fuel oil.3 Other fertilizers containing AN such as CAN (calcium ammonium nitrate with 27% N) detonated with a detonation velocity ~2500 m/s

[Edited on 26-5-2010 by pjig]

[Edited on 26-5-2010 by pjig]

franklyn - 30-5-2010 at 15:18

DE178620 - http://tinyurl.com/236bu4w
Ammonium Nitrate is prepared by mixing a solution of Calcium Nitrate
with excess Ammonia and passing Carbon Dioxide into the liquid.
Ca(NO3)2 + 2NH4OH + CO2 => CaCO3 + 2 NH4NO3 + H2O

.

The WiZard is In - 30-5-2010 at 18:49

Quote: Originally posted by runlabrun

well the reason for its insoluble nature is unknown.... NH4NO3 and CaSO4 are both alcohol soluble according to msds documents. The extent to which they are soluble or the temperature at which the solubility occurs to a great extent may be the source of the problem, alcohols frequently have a sharp curve on a solubility vs temperature graph whereas the same graph for water is usually more linear.
-rlr

When I have a question like this I take off the shelf —

Linke, William F
Suitabilities : inorganic and Metal-Organic Compounds
D Van Nostrand 1958

Me thinks your library will have a more up to date copy.

CaSO4 @ 25o C.

H2O 0.2084 gm in 100 gms solvent

Ethyl alcohol 0.314 gms 3.906% E Alcohol to 0.0029 gms
in 40.97% EtOH.

The WiZard is In - 31-5-2010 at 06:59

Quote: Originally posted by fatkangaroo

Looking for some help to do this reaction properly as I cant seem to get it right.
As I understand it the CN is dissolved into boiling water and the calcuim drops out as it won't dissolve in water.
Well I gave it a shot and the problem is everything dissolves and there are no solids to filter off. I boiled for ten minutes or so then put it in the frezzer. Nothing is coming out full stop.
Any help would be appreciated.

-----------
From Google.com/patents

PROCESS OF MAKING PURE AMMONIUM NITRATE.
[From ammonium sulphate and calcium nitrate.]
US Patent 986,304. March 7, 1911

When working with dilute solutions, the gypsum formed separates
out for the greater part; the small portion remaining in solution is
precipitated by concentrating the dilute ammonium-nitrate
solution, with the exception of a very small trace, corresponding
to its solubility in solutions of ammonium-nitrate. The solution
after being separated from the gypsum and after being
sufficiently concentrated crystallizes only ammonium-nitrate upon
cooling, since the gypsum, being more soluble in the cold,
remains in solution. Starting from pure calcium-nitrate a very
pure ammonium-nitrate is therefore obtained in this way. The
commercial calcium-nitrate however always contains, besides
alumina and iron-oxid, considerable quantities of magnesia and
magnesium-nitrate as impurities. The magnesium compounds are
dissolved during the double decomposition and are not removed
by concentration. If operating with equivalent quantities of the
two salts or with an excess of sulfate of ammonia, they are upon
cooling the concentrated .solution, precipitated for the greater
part simultaneously with the ammonium-nitrate with the result
that the incombustible residue in the ammonium-nitrate is
increased to such a degree that the latter cannot be used for the
production of safety-explosives.

See complete patent for details.

The WiZard is In - 31-5-2010 at 08:37

Quote: Originally posted by fatkangaroo

It may also be obtained, according to Ger. Pate. 166,746 and
184,144, and Fr. Pat. 465,683 of 1913, from ammonium sulphate
and sodium nitrate, either in solution or by fusion. It is best to
use excess of the nitrate: 132 kilos of ammonium sulphate and 85
kilos of sodium nitrate are dissolved in 250 litres of water and the
liquid concentrated at a temperature of 90°; after separation of
the slightly soluble sodium-ammonium salt, water is added to
form a saturated solution at 50°, the bulk of the ammonium
nitrate then separating when the liquid is cooled to 20°. It may be
obtained also from ammonium sulphate and calcium nitrate in an
autoclave at 150°.

http://tinyurl.com/3aaqhvn

------
Nydegger and Wedekind (B. P. 20907, 1909) state that
manufacture of ammonium nitrate from calcium nitrate (which by
its electrolytical production is a comparatively cheap starting-
material) has the drawback that the commercial calcium nitrate
contains various impurities, as alumina, ferric oxide, magnesia,
and magnesium nitrate. When decomposing calcium nitrate by
ammonium sulphate, the magnesium compounds enter into
solution along with ammonium nitrate, and in the evaporation
they are not removed, but remain in the crystallized ammonium
nitrate, making this useless for explosive purposes. They avoid
this by employing an excess of from i to 10 per cent, calcium
nitrate (or barium or strontium nitrate), which causes the
magnesium salts to remain in solution up to the last, after the
crystallization of the ammonium nitrate, even in cases where 10
parts MgO or upwards are present for 100 NH4NO3. From th
mother-liquor, the magnesia is recovered by an excess of
ammonium sulphate in the shape of magnesium-ammonium
sulphate. The same process is described in the Ger. P. 231394, of
Wedekind & Co.

Plantz (Ger. P. appl. P30765) gives prescriptions for obtaining pure
ammonium nitrate from crude calcium nitrate (" Norgesalpeter ").

http://tinyurl.com/2ar898o

&c., &c.

franklyn - 21-7-2010 at 07:15

* Ammonium Nitrate fractionally crystallizes from a solution of 8.5 parts Sodium Nitrate
to 13.2 parts Ammonium Sulfate chilled to - 15 ºC. Sodium Sulfate remains in solution.

Gas phase reaction of Ammonia with NO2 under 100 ºC
directly forms Ammonium Nitrate
2 NH3 + 2 NO2 => NH4NO3 + H2O + N2

.

quicksilver - 21-7-2010 at 16:35

I had a large amount of the fertilizer C.A.N. (15-5-0-0) product which I experimented with at length to find if it was feasible to yield quality ammonium nitrate in bulk & with low cost or trouble. I even was going to post various yields, pics, etc, etc. However, looking back, the most sensible thing is to find very large containers / vessels and work with several Kg units & be done with the damn thing* (after finding a method that is utilitarian for the individual, of course).
Many years back I was really taken with hobby rocketry and thought that a pound of high quality sulfur flour and commensurate weights of KNO3 would last as long as I would ever need it. Such was not the case. If it's really going to be used at length; it's worth making a large amount & being done with it.

The level of hygroscopisity and deliquescense of ammonium nitrate is such that if one lives in highly humid regions or cannot use the outdoors for other reasons, attempting large batche simply doesn't makes sense. Using an oven is so expensive that it becomes out of the question for a large scale return. Working with single pound units, while appropriate for determining what methods may be productive; is a serious time consuming agenda for a very common, inexpensive chemical. And while there's certainly nothing wrong with doing that once or twice for a pound or two; if one is really going to use that chemical at length - a Kg would really only last for so long.

*Forgive me but there is a certain aspect of twisted humor in being a "Nitrate Prince"; dipping one's hands into a 5 gal bucket of crystals & letting them run through one's fingers like a pirate with a chest of gold coins.

entropy51 - 21-7-2010 at 17:09

Quote: Originally posted by franklyn

* Ammonium Nitrate fractionally crystallizes from a solution of 8.5 parts Sodium Nitrate
to 13.2 parts Ammonium Sulfate chilled to - 15 ºC. Sodium Sulfate remains in solution.

Any water in there, Franklyn?

franklyn - 22-7-2010 at 04:19

@ entropy51 : The best I can do _

See bottom of pdf page 75 ( book page 49 ) here _

Manufacture of Explosives Vol I : Theoretical & Practical - 1896
http://books.google.com/books/download/The_manufacture_of_ex...

_________________

I 'm not aware that it forms a hydration adduct.
Anhydrous product always requires drying anyway , you know that.

.

Re Binders and coatings used to make AN "non-explosive"

pjig - 22-7-2010 at 18:04

In my latest findings I have found what seems to be even more discouraging in the coating that is used to make AN a non-explosive compound .

http://osdir.com/patents/Synthetic-resins/Anti-explosive-fer...

The coatings on the CAN are both water and hydrocarbonsoluble... Seems like they covered both basis.. My thought is create a possible environment that can sepperate these coatings, like ph or temp.

Any Ideas? Yara really did well, in making this stuff a real pain in the assssssss!

franklyn - 23-7-2010 at 07:17

Quote: Originally posted by entropy51

Quote: Originally posted by franklyn

* Ammonium Nitrate fractionally crystallizes from a solution of 8.5 parts Sodium Nitrate
to 13.2 parts Ammonium Sulfate chilled to - 15 ºC. Sodium Sulfate remains in solution.

Any water in there, Franklyn?

Thinking it over there seems something '" off " about this assertion
that I quoted. Given the solubilities of Na2SO4 and NH4NO3 I would
expect the ammonium nitrate to remain in solution not the Glauber salt.

Ammonium Nitrate Crystallization Curve.jpg - 55kB

Ammonium Nitrate Crystallization Curve.jpg - 55kB

$Na2SO4 fractional crystallization.gif - 35kB$

Separating out ammonium nitrate with methanol

midlifer - 22-12-2017 at 15:30

Just a few thoughts and opinions from experience (not deep knowledge) on this subject.

I have been experimenting with separating ammonium nitrate (AN) from both cold packs and fertilizer to use as an oxidizer in solid rocket fuel for model rockets. (No calcium nitrate involved. That's another complication for another time. I have dealt with calcium ammonium nitrate cold packs and have some ideas.) Both cold packs and fertilizer are coated with a substance (clay or silica) for anti-clumping purposes. No matter what you use as a solvent, filtering with qualitative paper should leave this behind and give you a clean solution of AN. Now comes the hard part.

AN is very hygroscopic and the only way to really drive out the water of crystalization is to heat your solution for a few hours close to AN's melting point of 169 degrees C. (How long you heat depends on how strong or weak your AN solution is. The stronger the better.) I did this using a heat plate, a 1000 ml Pyrex beaker, and a digital thermometer. When I was satisfied it had gone far enough (bubbles actually POPPING and intuition told me it was done), I let it cool. A few hours later, I was presented with a solid white disc of AN crystals. Hard as cement. (Dropping some into water produced the endothermic effect.) Be careful. Do some research. Keep your eye on the temperature. Don't let it get above 169. Do this at your own risk.

However, here is a better way. Dissolve the AN in methanol directly and filter it. (Methanol is not nearly as good a solvent as water, but it does the trick.) All the coating and most impurities will be left behind - toss them. Then put the solution in your freezer for a couple of hours after which you will see the AN has precipitated, forming a beautiful, thick layer of crystals on the bottom of your flask. (I have never seen AN precipitate out of water by cooling it. Perhaps I didn't have a strong enough solution. And if it does precipitate out, it still retains the water of crystallization. I think.) Filter this methanol solution and when done lay out the filter paper to dry. In an hour or so you have dry AN with no water of crystallization. At least that's my take on it. Correct me if I'm wrong, people.

yobbo II - 22-12-2017 at 18:43

You could use vacuum so that you do not need to heat the water solution to such a high temperature

Bert - 23-12-2017 at 14:24

Quote:

Dissolve the AN in methanol directly and filter it. (Methanol is not nearly as good a solvent as water, but it does the trick.) All the coating and most impurities will be left behind - toss them. Then put the solution in your freezer for a couple of hours after which you will see the AN has precipitated, forming a beautiful, thick layer of crystals on the bottom of your flask. (I have never seen AN precipitate out of water by cooling it. Perhaps I didn't have a strong enough solution. And if it does precipitate out, it still retains the water of crystallization. I think.) Filter this methanol solution and when done lay out the filter paper to dry.

Can any point to a graph or table of solubility vs. temperature for ammonium nitrate in methanol?

Yara (and others) sell ammonium nitrate fertilizers compounded with desensitizers to prevent the use of ammonium nitrate fertilizers for ANFO, such things as fly ash and oily stack condensate hydrocarbons from coal burning plants, along with gellants/other water activated gluey stuff to jam up filter paper and hinder easy purification of ammonium nitrate fertilizers.

Have any tried methanol extraction on such products?