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Author: Subject: Cold pack disappointment
Rogeryermaw
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[*] posted on 27-5-2011 at 14:58


if you are able to get the NH4NO3 and not the KNO3 or NaNO3 but you prefer the alkali metal nitrates just dissolve the NH4NO3 in water then add stoichiometric ammount of KOH or NaOH. do this outside if possible because copious amounts of NH3 gas will be released. heat the dissolved salts lightly to drive off the remaining NH3 and reduce the water content. you will be left with beautiful, clear, needle shaped crystals of the nitrate of the alkali metal hydroxide you choose.



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[*] posted on 27-5-2011 at 15:12


Quote: Originally posted by Rogeryermaw  
if you are able to get the NH4NO3 and not the KNO3 or NaNO3 but you prefer the alkali metal nitrates just dissolve the NH4NO3 in water then add stoichiometric ammount of KOH or NaOH. do this outside if possible because copious amounts of NH3 gas will be released. heat the dissolved salts lightly to drive off the remaining NH3 and reduce the water content. you will be left with beautiful, clear, needle shaped crystals of the nitrate of the alkali metal hydroxide you choose.


That is a bit dozy.
Almost any nitrate source can be extracted with water and then treated with Lo Salt or an equivalent source of potassium chloride to form potassium nitrate which readily crystallises.
The solubility curve of potassium nitrate is such that very high purity material is easily isolated and it is not hygroscopic.
The residual solutions can be added to the compost heap or tipped down the drain and no clouds of ammonia gas!
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Rogeryermaw
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[*] posted on 27-5-2011 at 17:45


you are correct of course but when i do this myself i either collect the ammonia in water to make my own solution or run it through a drying tube with CaCl2 and condense it through a liebig using acetone cooled with dry ice. i have a vessel similar to the steel retort i pictured on the phosphorus thread.

http://www.sciencemadness.org/talk/viewthread.php?tid=65&...

only with a valve instead of a downpipe.

edit: the KNO3 or NaO3 (depending on the hydroxide used) is just a bonus.


[Edited on 28-5-2011 by Rogeryermaw]




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Rogeryermaw
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[*] posted on 3-6-2011 at 00:42


17 packs of this. NH4NO3, clean, white, no visible impurities. these are from the enviro safety people. 92 cents each plus shipping.

NH4NO3.jpg - 57kB




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hyperkinetic
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[*] posted on 9-6-2011 at 04:04


I've spent some earnest foot time but can only report that none of the local dollar stores or Zellers carry cold packs. Walmart staff don't know if they do or if they don't. They don't have any in right now but it may just be because their stock is sold out.

I don't have a condenser, nor any need for large amounts of ammonia but I do want ammonia chloride so the KCl route is my intended path.

I'm still waiting on a filter funnel, the first one I ordered arrived in several pieces.

Thanks for the advice :)
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cyanureeves
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[*] posted on 9-6-2011 at 04:27


last time i checked walmart they only had mueller brand and it was urea but the sister store wal-greens has a perfect ammonium nitrate product. it is super white and it sells for about 2 dollars for 80 grams. are you going to bubble the chlorine into ammonium hydroxide for your ammonium chloride? how do you make yours?
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sternman318
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[*] posted on 9-6-2011 at 10:07


Target brand ( Up & Up) instant cold packs contain ammonium nitrate, but it is pricy!
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LanthanumK
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[*] posted on 9-6-2011 at 10:31


If you want ammonium chloride, why not just react NH3 with HCl instead of NH4NO3 and KCl?
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MrHomeScientist
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[*] posted on 9-6-2011 at 13:36


My source for ammonium nitrate is Walgreens - they have instant cold packs with pure white prills of NH4NO3. When dissolving in water I noticed some froth floating on the solution, so it's probably got anti-caking agents in there, but that is easily filtered out.
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hyperkinetic
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[*] posted on 13-6-2011 at 11:21


I wanted the ammonium chloride to play with ice baths, It seemed to make sense to produce it at the same time I produced the KNO3 by extracting it by boiling down the filtrate.

However, I've been running numbers and it really doesn't make sense for me to take the KCl route. I'd have to discard too much of each product to purify them versus waiting, getting some KOH and running the ammonia off to be collected and chlorinated.

@Rogeryermaw: Thanks a lot for making me rethink. Now I have to do twice the work ;)
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Rogeryermaw
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[*] posted on 13-6-2011 at 13:56


Quote: Originally posted by hyperkinetic  


@Rogeryermaw: Thanks a lot for making me rethink. Now I have to do twice the work ;)


well we do what we can. ;) by the way the NH4NO3 recrystallizes beautifully:

http://www.sciencemadness.org/talk/viewthread.php?tid=14644&...




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[*] posted on 14-6-2011 at 05:47


Can't believe I didn't see this thread in my normal browsing... Not 2 hours ago I posted something similar asking if OTC NH4NO3 was still around - Now I know where to look!

I suppose, in the US at least, I should check out target and the local dollar stores? It seems that in the last couple years nitrate salts are disappearing from the shelves (try to find spectracide in WNY, I dare you!) My main question was whether my old standby, nexcare cold-packs, still had nh4no3 or whether they went to urea like everyone else.

So here's the new question - For those of you who are able to find it, what are you paying for a given quantity? The nexcare packs were 150g for $1.50usd - $.1/g, or ~$4.50/lb - I haven't even sought one out in 3-4 years, so what's the market like now? The holidays are coming up quick and I'm curious as to the economics of nh4no3/k2co3 -> kno3 versus buying local or ordering... The ONLY local source left to me this year is TSC with some brand I've never worked with for $8/lb...




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hyperkinetic
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[*] posted on 14-6-2011 at 07:04


I'm looking forward to those pretty crystals, I'll be able to run them today.


About nitrate stump remover - It seems it is not the stores dropping the product, it is the manufacture dropping the product.
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hyperkinetic
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[*] posted on 14-6-2011 at 19:02
Some interesting observations






I’ve never tried to purify dirty cold pack prills before and rather then just “do so” I wanted to have some fun with it. In this vein I decided I would come to an accurate measurement of the dirt/nitrate ratio and the exact amount of nitrate per cold pack. I had planned on dissolving both packs into the same 250ml of water, which would have allowed for a comfortable extraction from the adulterants with some immediate re-crystallizing on cooling. The remaining solution would later be used as the starting point to re-crystallize some already cleanish white prills prior to treatment with KOH.

First one pack was to be dissolved, and filtered. The filtrate was to be removed and then the second pack run through the same procedure with the same solution at a temperature greater then 60°C to insure complete removal of the nitrate. A safe and idiot proof extraction.

So, having set up everything I began by cutting open a cold pack, weighing the prills (150g) and slowly adding the dirty prills to ~80°C water while stirring with a glass rod.

Once the dirty prills where all in the beaker and about half dissolved, they surprised me by started to softly effervesce. I set the mixture in front of an extraction fan and stirred while adding warm water to further dilute the muddy mixture.

The smell suggested ammonia; pH paper confirmed. The mixture continued to emit strong ammonia fumes until it was cooled to “warm to the touch but not hot” and severely diluted. The pre-prill fluid volume was 250 ml, it was up to ~500ml afterwards and I’d no idea how much of that was water and how much was from the prills crude, my attention had been on monitoring whatever it was that was happening in the beaker.


The liquid that came from this was muddy and brown much like water in the bottom of a well agitated pothole. Its surface was free of any of the anti caking agent scum that other people have described when they dissolved clean prill cold packs. I transferred the mixture to a filtration funnel and sat back to watch.


The liquid came through a single paper very muddy and brown. Sand and larger grit where being effectively held in the funnel but fine silt was passing through the single paper, no surprises there. Oh wait.

Strange thing number two.

Eventually it became clear that the liquid being pulled through the funnel was settling into three layers in the flask. The bottom layer was made of insoluble sediment, the middle layer was a dark but translucent liquid and the top layer was a lighter grey-brown totally opaque liquid. The layer separations where very distinct.

The mixture had a homogenous (but unmeasured) temperature and did not show any tendency to form multiple liquid layers before filtration.

The layers vanished when the liquid was swirled and a little more water was added to wash out whatever salts where still locked in the filtrate/funnel. Once the filtrate was mostly dry I broke the vacuum, set the filtrate aside and ran the solution through the funnel a second time but now with three filters. This gave a clear almost silt free fluid, nothing unusual happened. The resulting solution was obviously far more dilute then the 250ml I had intended and was set-aside in a large flask.

Abandoning my original plan I added the second cold pack (146grams of dirty prills) into 300ml of 90°C water in an attempt to re-create the previous results under controlled conditions. The prills where almost fully dissolved this time before the fumes became noticeable. Testing showed ammonia, Ah ha! Pointless confirmation! I tested the pH of this solution, something I had neglected to do in the first case. With the prills mostly dissolved and the slight effervescence peaking it showed as being weakly acidic. I tested it again a few minutes later when the soluble portion was fully dissolved and it tested as being essentially neutral.

I filtered this mixture through a triple stack of filters from the start and was just about to add the last ~50 ml of muddy mix when a random flux in the home water pressure let water flow back from the aspirator into the flask diluting the contents 50/50 with tap water, ah life – such sweet sorrow. The liquid that had been pulled through the filter before this point was clean, clear and showed no sign of layering.

Satisfied that I was frustrated and sufficiently distanced from any explanation or desired result; I cleaned up, stored the solutions and had dinner.

The ammonia fumes perplex me; I’ve never experienced that before nor, to my knowledge, should I have without having boiled the nitrate solution. It was just like I had added a few flakes of KOH to a beaker of warm saturated ammonium nitrate.

To re-state/clarify, all glassware was scrupulously cleaned before use. The water was distilled and started at no more then 80°C the first time and 90°C the second time. The temperature of the water was to be allowed to fall with the dissolution of the ammonium nitrate in both cases.

I do not think that more then a few cc of gas were created in each of the reactions. Had the dissolving water started at room temperature I believe no pressure would have been generated, and no fumes observed, due to the increased solubility of the ammonia in cool water. It seems likely that had the cold pack been used it would have ended up with a elevated pH, assuming the cold pack water was neutral to start with.

I believe that the triple layer that I observed during the filtration of the first solution may have been caused by residual ammonia boiling out of the still warm solution while under vacuum. The escaping gas could have found nucleation points on the finer silt particles and lifted/held them close to the surface where gas was able to escape. I think that it is plausible that after liquid had been de-gassed it was able to settle forming the middle layer. I think that the formation of gas and consequent suspension of silt particles would explain the colour/opacity/layers. Is that reasonable? Thoughts?

As for the evolution of ammonia, I wanted to validate my assumption that the unexpected ammonia production was a product of some unknown in the dirty prills rather then a gap in my pre-search. I searched the web to confirm the observance of ammonia nitrates stability data in my procedure. Finding no deviations I prepared a final experiment to isolate and assign the deviated results to chemical prill contamination rather then the procedure.

I heated 100ml of distilled water to boiling, poured it into a beaker. For this experiment I added some of the white pure looking prills of ammonium nitrate from the cold packs mentioned earlier in the thread. It was added very slowly with continual stirring using a glass rod and watching for the formation of gasses. I achieved saturation with no sign or smell of gas evolution and no affect on the pH paper that had been surreptitiously used to verify the perceived lack of ammonia vapour.

When it seemed evident that this hot, saturated solution was indeed stable I added dirty prills from an already open dirty cold pack. The prills where stirred into the solution two or three at a time until between fifteen and twenty where in the beaker. Unmistakably tiny bubble trails formed and if I listened very carefully I could hear the prills softly bubbling at the bottom of the beaker. The solution tested as being very slightly acidic, and the air above it being very basic. With time the pH returned to neutral and the solution was discarded into remaining unfiltered solution from flooded filtration.



Right now I’m preparing to sacrifice a beer to Murphy and his mighty law while doing a further post mortem on this… fiasco… the simplest tasks are always the most complicated.


The reason I posted this somewhat rambling account is that it has made me question that the contamination of the nitrate is solely inactive dirt.

I would like to know just what it is that is causing the ammonium to off gas from the solution. I intend to try and find out for the sake of sheer curiosity, I found a paper on adulterating Ammonium Nitrate that suggests several possible additives.

“Ammonium nitrate: thermal stability and explosivity modifiers”
Jimmie C. Oxley, James L. Smith, Evan Rogers and Ming Yu
Chemistry Department, University of Rhode Island, Kingston, RI 02881, USA

http://www.sciencedirect.com/science/article/pii/S0040603101...


I’d love some ideas, suggestions or leads.

On an off topic line of curiosity, a number of local EMTs talk about stupid cases where people have decided that opening an activated cold pack and covering themselves in the cold pack solution was a logical step to increase the cooling solutions efficacy. Apparently not uncommonly this has resulted in rather bad chemical burns. The MSDS for ammonium nitrate clearly establishes the possibility of a chemical burn with prolonged skin contact but I can’t help but wonder if there is some free ammonium being generated which is partly to blame.


I hope this is the coherent and accurate post that it is in my head. I'm exhausted and going to go get on with the beer sacrifice to good old Murphy and his immutable law, I'll check it over again tomorrow.
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[*] posted on 14-6-2011 at 19:52


Here's some reading: http://www.efma.org/documents/file/Guidance_storage_Hot_Ammo...
Among other things, they say that ammonium nitrate solutions gradually lose ammonia during storage. Also N2O and NOx. Some ions can accelerate decomposition, as can acidic conditions (which they define as pH < 4.5).
Anyway, explaining the ammonia offgasing is a lot easier than making sense of the accompanying pH changes... maybe ammonium bicarbonate as impurity, making things more basic (neutral) as it passes into ammonium carbonate? The CO2 that offgases along with the NH3 might not show up in your pH testing of the air above the solution (I'm assuming you used pH paper).
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[*] posted on 15-6-2011 at 10:08


Thanks Bbartlog, I read through the link, it was very useful in figuring this out. I couldn’t find a smoking gun so I tried to back door the problem.

I started looking for places which made and sold ammonium nitrate in Canada and fluked on a Quebec company who sold bulk “Calcium Ammonia Nitrate”. I followed through on this and found that Rapid Aid uses this mixture for cold packs. On their website they have this

“Effective November 5, 2010, Rapid Aid Instant Cold Packs will no longer contain Ammonium Nitrate. The new chemical being used is Calcium Ammonium Nitrate, which is not a restricted chemical as it contains less than 28% nitrogen.”

And guess what? Rapid Aid supplies Shoppers Drug Mart who sells it under their Life brand.

All the cold pack bags say is that they contain ammonium nitrate. The actual mixture is by weight 78% ammonium nitrate, 20% dolomite and 2% Magnesium Nitrate.

Who knows what trace ions are lurking in the dolomite sludge.

http://www.rapidaid.com/products/

New cold pack MSDS
http://www.rapidaid.com/products/MSDS_CAN_V04.pdf
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Arthur Dent
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[*] posted on 15-6-2011 at 10:17


Quote: Originally posted by hyperkinetic  
...All the cold pack bags say is that they contain ammonium nitrate. The actual mixture is by weight 78% ammonium nitrate, 20% dolomite and 2% Magnesium Nitrate.


:o

Damn!
i'll have to investigate if my stock is composed of the old or the new packs. The Ammonium Nitrate I have is perfectly clean, pure white and dissolves completely without barely any turbidity...

...mmhhhhhh... (in the voice of Marge Simpson)

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cyanureeves
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[*] posted on 15-6-2011 at 11:06


dang it, i got one dirty ammonium nitrate package that was given to me and added it to my clean prills thinking it was just old. either way i'm hoping it wont affect my nitric acid distillation.
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LanthanumK
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[*] posted on 15-6-2011 at 11:40


Why don't you dissolve the whole set of prills in water and filter? This would work if the contaminant is insoluble.



hibernating...
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hyperkinetic
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[*] posted on 15-6-2011 at 12:03


Quote: Originally posted by mr.crow  

Do you think CAN could stand for calcium ammonium nitrate? That is also a fertilizer mix.



:(

You were dead on. ;)
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cyanureeves
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[*] posted on 16-6-2011 at 04:36
recrystalize


Quote: Originally posted by LanthanumK  
Why don't you dissolve the whole set of prills in water and filter? This would work if the contaminant is insoluble.
the nitrate did salt out first leaving a dirty liquid behind that i can discard or mix with sulfur and charcoal and burn it.
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[*] posted on 22-6-2011 at 23:28


Checked a little closer and the results are disappointing - For anyone wondering, WalMart's new brand is garbage - urea, NH4Cl and CaCl. Target and RiteAid both had ammonium nitrate packs, for ~5.50 and ~3.00 respectively, in 2-packs - However, opening up the box, a quick look and feel lead me to believe that these are half the size they used to be. The old nexcare packs I used to grab always had 150 grams in them, I'd estimate somewhere between 60-80 in the ones I checked out.

Still need to hit the dollar stores, but the findings so far don't look good. Has anyone else noticed that the packs that are out there seem to be smaller? I haven't bought one in ~4 years, but I seem to remember them being quite a bit more substantial...

...On the bright side, my K2CO3 experiment is looking good - Should be able to pull 1-2 lbs from the ash leachate after cleaning it up. Since it appears that a few of you are thinking in the same direction as me, failing ammonium nitrate, does anyone know of any calcium nitrate or "CAN" fertilizers by name in the US? Anything I could find at a "box store?"




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[*] posted on 2-9-2011 at 14:47


Content of instant cold pack`s has chanced in eu because some law in 2006. Last time when i purchase whole box there was paper inside box which was writted that content has chanced although behind pack`s label was writted ammonium nitrate and water. inside was something called nitrogenous salt? It was german made pack`s.I also find pack` with carbamide inside
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[*] posted on 2-9-2011 at 16:52


Blame meth cookers on that.

Using ammonium salts as a source of ammonia in nazi meth recipes surely played a role on why their sources are getting shut down.
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[*] posted on 2-9-2011 at 23:25


Ok I have heard many different reasons why content has chanced, here is few:
-content equals TNT
-airport security problems
-eu-law 1907/2006
That TNT excuse is nonsense wich we all now,but i don`t think cooking meth is a problem in europe,so it must be those other reasons
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