Sciencemadness Discussion Board - Cold pack disappointment

Cold pack disappointment

mr.crow - 21-5-2011 at 20:16

I used up all my home made KNO3 today lighting off smoke mixes for the Victoria Day holiday with the GF. To make up for this I already got some NH4NO3 cold packs to make some more.

The packs are mostly dirt with the solution resembling mud. Usually I get around 250g, but these measured 292g.

So it looks like the best Canadian source of ammonium nitrate is getting cut off

hkparker - 21-5-2011 at 22:36

Same here in the US, cold packs are mostly urea now, its hard to find the ammonium nitrate ones.

entropy51 - 22-5-2011 at 07:36

Quote: Originally posted by hkparker

Same here in the US, cold packs are mostly urea now, its hard to find the ammonium nitrate ones.

It may just be a local thing. NH4NO3 cold packs were rare here a few years ago, but now the local CVS pharmacy stores have loads of them. The contents are quite pure too.

mr.crow - 22-5-2011 at 08:06

Well its the same cold packs I used before and I think they still have ammonium nitrate. Usually there is a tiny amount of dirt that I filter out, now there is a 50mL layer of mud on the bottom of the beaker.

smaerd - 22-5-2011 at 17:02

I recently bought some in the US that was pure white, not grunge or dirt or anything.

mr.crow - 24-5-2011 at 09:55

I guess its hit or miss. There was indeed mud in it, a very fine sand. Sort of like clay. I filtered it out to get a slightly yellow solution. Then I mixed with KCl solution, boiled off some water, cooled, etc.

KNO3 crystals look like Superman's Fortress of Solitude

smaerd - 24-5-2011 at 11:18

If your looking for ammonia, then maybe diammonia phosphate at brewstores would work. If your looking for nitrates, stump removers have it right?

MagicJigPipe - 24-5-2011 at 12:28

I have found one stump remover that contained NaNO3. It was really expensive, too.

Up until about a year ago I could buy the NH4NO3 cold packs just about anywhere. I sure hope they aren't gone now. I should stock up on a few kgs the next chance I get.

Bot0nist - 24-5-2011 at 14:26

I am not sure if you have dollar stores in CAN, but I just went into Dollar Tree today and they had insta-cold compresses for a $1.20 usd and the ingredients listed are water and ammonium nitrate. I bought six packs. Just opened them and they contain an inner bag with water and the outer bag is filled with ~55 grams of pure white prills (little beads). Tested positive for both nitrate content and ammonia evolution and no insoluble(dH2O) impurities were observed. Prills were ground up (rolling pin), dehydrated in low heat, and then packaged in an airtight container to help with hygroscopy issues. I would post some pictures, but I am sure you all now what to look for. Just saying, keep looking. I live in a relatively large city in a conservative state(not sure if that matters) in the USA but have had no trouble finding reagents, even though many claim that things like toluene, glycerol, and other, once common OTC chemicals are becoming scarce. I just haven't seen it here. Maybe I'm just lucky.

cyanureeves - 24-5-2011 at 18:13

dollar general has them too for $1.50 and it weighed more than walmarts. it was my secret store but i will share because this place has parted with lots of info.

MagicJigPipe - 24-5-2011 at 20:11

Great. I hadn't thought about checking Dollar General and Dollar Tree again. I know they once had them but had just assumed they had gotten rid of them like everyone else. Kroger used to have them and so did Wal-Mart. I doubt they do anymore.

hyperkinetic - 25-5-2011 at 09:05

Shoppers Life brand cold packs still contain ammonia nitrate, some packs contain clean white pills with the odd discolored lump and other packs are much larger very dirty prills(also tiny pebbles! WTF?). Only some Shoppers carry cold packs and some that carry cold packs carry a brand name version and not the Life brand, the brand name ones are urea.

I bought some recently and after gutting them found that I had both the pure prills and the dirty prills. The solid volume for the two purities is roughly the same, the packs with the dirty prills felt heavier, but I did not have a chance to weigh them.

The packaging, bar code, manufacture information and cost is all the same so there is no way to tell them apart - unless you open a box and hold an individual pack up to a light.

Edit: Added picture. Nope picture to big. Fail. Resizing.

Edit2: De-fail.

[Edited on 25-5-2011 by Hyperkinetic]

[Edited on 25-5-2011 by hyperkinetic]

mr.crow - 25-5-2011 at 09:22

Quote: Originally posted by hyperkinetic

Shoppers Life brand cold packs still contain ammonia nitrate, some are clean white pills with the odd discolored lumps and others are much larger very dirty prills(also tiny pebbles! WTF?). Only some Shoppers carry cold packs and some that carry cold packs carry a brand name version and not the Life brand, the brand name ones are urea.

I bought some recently and after gutting them found that I had both the pure prills and the dirty prills. The solid volume for the two purities is roughly the same, the packs with the dirty prills felt heavier, but I did not have a chance to weigh them.

The packaging, bar code, manufacture information and cost is all the same so there is no way to tell them apart - unless you open a box and hold an individual pack up to a light.

Yes, those are the ones I am using. They are either reasonably clean or very dirty. Dirty ones were heavier.

So maybe check each box and buy the lighter ones? Like buying melons at a market, haha

hyperkinetic - 25-5-2011 at 16:28

Fantastic. I'll relish bouncing boxes of cold packs in each hand like melons, there goes the illusion of sanity.

I wish I had known that I had a pack of each kind of prill, before I slit them open so I could have made Quantitative measurements. I'll try and get another pack of each and measure the ingredients/purity.

It seems to me that the dirty prill Cold packs must contain substantially less nitrate then the clean prill packs. I don't appreciate paying almost 10 dollars for dirty fertilizer.

I'm going to have to start collecting night soil. I'll toss in a couple printouts of the nitrate regulations to give the bacteria something good to feed on, apparently they thrive on the excreta of the male members of Bos taurus.

Rogeryermaw - 25-5-2011 at 20:14

https://www.envirosafetyproducts.com/disposable-cold-packs.h...

i ordered 15 of these and they were perfect. clean white crystals, although a touch moist, that's not hard to fix. orders over 10 are 92 cents each.

here is another supplier carrying the same product in bulk but you have to request price quotes.

http://certifiedsafety.thomasnet.com/viewitems/certi-cool-tr...

[Edited on 26-5-2011 by Rogeryermaw]

Cold packs in cold Canada

hyperkinetic - 27-5-2011 at 06:12

Thank you Roger, but I’m very hesitant to try ordering ammonium nitrate across the border. My needs for it are very small and directly related to metallurgical pursuits, I would prefer a source of potassium nitrate or sodium nitrate but I have not been able to find them OTC.

I have a hypothesis on the nitrate adulterants. Under the existing laws any ammonium nitrate with a high purity is a restricted substance; subject to intensive scrutiny, record keeping and end use monitoring. (Oh noes! Evil people want to killlz uzz!!!

)

Restricted ammonium nitrate compounds are defined as;
“(a) ammonium nitrate in solid form at a concentration between 28 and 34% nitrogen;”

Relevant legislation lists no tolerances for defined purities of ammonium nitrate. The ban appears to be both blind and blanketing, the only exceptions to its scope are educational, government, and health institutions.

I suspect the adulterant is incinerated soil, which added as an inert material to reduce the total nitrogen value to below the restricted percentages.

This could mean the clean prills came from packages that were produced before February 2008.

While I can not identify the manufacturing dates from the Lot numbers on the cold packs, they are differently appended. The Lot number on the clean prills is followed by the letter "A" and the dirty prills followed by the letters "CAN".

I infer that the clean prills were manufactured in the United States by the letter 'A' while the dirty prills (CAN) where ether adulterated in Canada or fully synthesized in Canada.

Both packages do claim "Made in Canada" but my understanding is that this only means that the components were assembled in Canada.

The box of cold packs with the clean prills came from a pharmacy housed near a hospital. It would be reasonable to assume that their cold pack sales would have been very slow or not at all given the ready access to ice/cold packs from the hospital. The cold packs may also have been in a forgotten box, which was pulled from the shelves but now sold.

My suggestion would be to visit pharmacies near hospitals or even in hospitals and juggle any of the cold pack boxes they have out, maybe there are more of the clean prills sitting on forgotten shelves.

I find it unlikely that the clean prills are intentionally distributed or sold anymore given the scope of the restrictions placed on pure ammonium nitrate product.

mr.crow - 27-5-2011 at 06:45

Some muslims tried to buy tons of AN to build a bomb and got busted. They wanted to blow up the Toronto Stock Exchange building right across the street from where my dad worked at the time.

So of course they immediately put in laws to ban AN then other nitrates and chlorates. >: ( thanks a lot

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

Bot0nist - 27-5-2011 at 06:45

I understand your apprehension, but I imagine that ordering small amounts of NH4NO3 will not bring much suspicion.

Don't order 500kg and nitro-methane of course, but I bet a few ounces to a pound will not raise many eyebrows.

hyperkinetic - 27-5-2011 at 08:46

I do not know if the CAN stands for CAlcium Nitrate but it seems unlikely. The dirty prills produce a very cloudy solution in water, but the solution does not become noticeably more opaque with the addition of sulfuric. I will test them again when I have better filtering capacities and can achieve a clear solution.

Perhaps the ammonium nitrate is being produced from calcium nitrate, the import of which is not restricted.

As for terrorism and ammonium nitrate, the 2008 explosives act was by the governments admission and statements, derived from the 9/11 terrorist attacks with only lip service made to Toronto plot.

Mass purchases of ammonium nitrate were already being monitored and where used as a trigger point for the arrests of the Toronto bomb plotters. Before you begin blaming an entire religion for the restriction of a chemical you should take note that by your logic ammonium nitrate faces intense scrutiny and restriction because of the actions of a Christian terrorist.

The truth of the matter is that ammonium nitrate was raised into the public awareness as a result of the vivid demonstration of its powder during the Oklahoma bombing and it has suffered ever since, the religion of the individuals involved is of no consequence. It was restricted because of intense public chemophobia and ignorance.

@ Bot0nist – I agree in theory, I don’t think small amounts would ring to many alarm bells and I think it may even be okay legal to import an impure grade but I’d rather stay clear of potential spider webs. They tend to be sticky and it feels like there are more spiders every day.

Rogeryermaw - 27-5-2011 at 08:52

failing a good, clean source, you could always dissolve in water, filter, and re-crystallize.

hyperkinetic - 27-5-2011 at 09:07

Thank you Roger, my current plan of attack is to dissolve->filter-> recrystallize->add KCl->recrystallize and so on.

mr.crow - 27-5-2011 at 09:23

Its ok, I'm not actually ignorant. And yes their religion is important because it is so closely tied with their political views and motivations. Just like with McVeigh, as you mentioned, being pissed at the Waco Seige. Ignoring that would be like assuming a murderer never met his victim before and making up your own motive that sounds plausible. I believe normal Muslims are hurt the most by fundamentalists.

They were probably planning the law for a while and used it as a way to get it passed. Sort of like when another religiously oriented person lit his panties on fire in an airplane and now everyone gets to go through the naked scanners at the airport. Its been a long time since Oklahoma City and 7 years after 9-11 to ban something obviously used for explosives (in 2008). I think chemicals suppliers only started enforcing it as recently as this year based on experience with one of my sources.

Anyways sorry to get off topic and start an argument. I will look for the A cold packs next time I need some.

TheAlchemist - 27-5-2011 at 09:23

Blanket bans and restrictions placed on chemicals only make it harder for the decent, law abiding citizen (including well-intentioned hobby/home chemistry enthusiast) to acquire them. Determined terrorists and drug cooks will always be able to acquire the materials they need for their nefarious activities.
If one was desperate enough, they could obtain ammonium nitrate from the leachates of decomposing nitrogenous waste, like horse manure. In fact, this was successfully accomplished on a BBC educational science series called 'Rough Science'. Are the authorities going to make horse manure a restricted substance?
I personally have made pure chlorates from nothing more than potassium carbonate derived from the purified soluble extracts of wood ash, a chlorine gas generator from an adapted electrolytic cell containing concentrated brine, and a heat source for the disproportionation of hypochlorite. Are the authorities going to restrict the acquisition of pvc tubing, basic glassware, wood, table salt and batteries?
I must admit, as a home chemistry enthusiast, making your own chemical reagents is often far more satisfying than buying them OTC or from chemical suppliers. Making your own reagents gives you the opportunity to improve your practical technique, and learn more chemistry along the way!

[Edited on 27-5-2011 by TheAlchemist]

mr.crow - 27-5-2011 at 09:29

Quote: Originally posted by hyperkinetic

Thank you Roger, my current plan of attack is to dissolve->filter-> recrystallize->add KCl->recrystallize and so on.

Yes, filtering did remove all of the mud. The solution was only slightly cloudy/yellow. If you are feeling advanced you can filter it through celite or diatomaceous earth.

I don't recommend recrystallizing the NH4NO3 directly because of its extreme solubility. It did work but probably still has tons of water trapped in it.

The KCl method uses a large volume or water producing huge crystals. KNO3 has the perfect solubility curve for this.

Arthur Dent - 27-5-2011 at 10:14

The brand I buy at the dollar store in my area goes under the name:
AID+PLUS Cooling Instant Ice Pack. That's the good stock! The bag contains about 100 grams of Ammonium Nitrate

The prills are perfectly dry, small and snow white. Dissolved, it gives a clear solution. mixed with a bit of NaOH, it gives off a strong ammonia smell. Package contents states: Ammonium Nitrate, Water. The bag inside the box says "made in China"

I'll stock up on these because they seem to be the best source right now.

Robert

Rogeryermaw - 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.

ScienceSquirrel - 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!

Rogeryermaw - 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]

Rogeryermaw - 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.

hyperkinetic - 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

cyanureeves - 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?

sternman318 - 9-6-2011 at 10:07

Target brand ( Up & Up) instant cold packs contain ammonium nitrate, but it is pricy!

LanthanumK - 9-6-2011 at 10:31

If you want ammonium chloride, why not just react NH3 with HCl instead of NH4NO3 and KCl?

MrHomeScientist - 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.

hyperkinetic - 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

Rogeryermaw - 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&...

Intergalactic_Captain - 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...

hyperkinetic - 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.

Some interesting observations

hyperkinetic - 14-6-2011 at 19:02

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.

bbartlog - 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).

hyperkinetic - 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

Arthur Dent - 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.

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)

Robert

cyanureeves - 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.

LanthanumK - 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.

hyperkinetic - 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.

recrystalize

cyanureeves - 16-6-2011 at 04:36

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.

Intergalactic_Captain - 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?"

bonelesss - 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

simba - 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.

bonelesss - 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

Steve_hi - 3-9-2011 at 01:14

all this screweing around for ammonium nitrate !
I don't understand why you guys just don't order it.
In Canada I bought 500g ACS for 19.95 from NewHorizons in BC
all you have to do is fax 2 pieces of Photo Id.

bonelesss - 3-9-2011 at 01:37

Do you now what happened in Norway a few month ago?
In Nordic countries public officers keep eye on AN-fertilisers unless you are a farmer and still you need some kind of licence i quess.

Acetic Acid - 3-9-2011 at 10:05

You paid 19.95 for 500 grams of NH4NO3. That's a pretty good deal. However, in instant cold packs a few weeks ago, I paid $5.29 for two instant cold packs. They look very pure and the contents were around 150 grams each.

You can buy as many as you want and you won't be questioned about it.

Roger86 - 3-9-2011 at 10:19

Quote: Originally posted by Acetic Acid

You paid 19.95 for 500 grams of NH4NO3. That's a pretty good deal.

Actually in my country with 19 american dollars you could buy 40 kg bag of AN

Acetic Acid - 3-9-2011 at 10:19

Also, the same CVS had some (reusable) instant hot packs that contained hot-ice ready sodium acetate. I prefer to make it myself from cleaning vinegar and baking soda, but the packs are also an option.

Acetic Acid - 3-9-2011 at 10:20

What? Where??

Roger86 - 3-9-2011 at 10:46

In finland its sold at 'agrimarket' chain for around 16€ per 40kg bag.Also they sell KNO3 for 4€ per kg.But i dont believe finland is the only country what has cheap ammonium nitrate, go look for it as fertilizer, but to be noted they only sell in bulk.Smallest bag they sell in is 40kg, but if you have storage space, go for it :cool:

i did some research (actually very little) but in usa you should look this video

http://www.youtube.com/watch?v=VlBk_98uk_Y

Acetic Acid - 3-9-2011 at 10:52

Ah yes, economies of scale. Buying more is always better.

uchiacon - 3-9-2011 at 20:18

Guys, really? All this effort for potassium nitrate? It's a fertilizer for christ's sake, and I'm sure it's going to be harder to find ammonium ntirate than potassium, what with one being favoured by a certain minority that likes massacring scores for a political message...

It really isn't that hard to find potassium nitrate, lol.

Neil - 4-9-2011 at 07:02

CAN is designed to decompose on dissolving and heating while producing large amounts of filter clogging sludge via precipitation of magnesium hydroxide to make it difficult to filiter the ammonium nitrate out of it.

The magnesium nitrate is readily precipitated by the ammonium which leads to a decrease in pH as the magnesium precipitates out leaving it's nitrate in solution.

The decrease in pH makes the ammonium nitrate more liable to off gas ammonia which further allows the pH to drop until the carbonate begins to react which stabilizes the pH while pumping calcium and more magnesium into solution.

the stabilized lower pH causes the ammonium nitrate to remain unstabilized which allows more ammonia to leave the solution allowing more calcium into the solution.

A solution of nutral ammonium borate can be used as a stabilizer, CAN dissolves into a hot ammonium borate solution without off gassing ammonia and with reduced precipitation of magnesium hydroxide.

The formation of insoluble calcium borate occurs but this is helpful, preventing the formation of calcium ammonium nitrate and maintaining the ammonium nitrate.

Hot filter chill and collect crystals. No off gas and little waste. If ammonia starts to come out of solution add a bit more ammonium borate.

the KNO3 and potassium borates produces by adding KOH are easily separated leading to fairly pure KNO3.

KNO3, nitric, and KOH are often stocked by hydroponic shops, Sales of imported KNO3 are restricted in Canada, sales of produced in Canada KNO3 is much less restricted IIRC.

Sales of ammonia nitrate is banned in Canada except under strict circumstances if it contains greater then 28% nitrogen by weight IIRC. Purchasers need to be monitored aka on government watch lists.

Neil - 4-9-2011 at 07:15

Quote: Originally posted by uchiacon

...it's going to be harder to find ammonium ntirate than potassium, what with one being favoured by a certain minority that likes massacring scores for a political message...

No actually, it is banned because idiots keep on repeating stupid things like that without doing any fact checking.

Chordate - 11-9-2011 at 05:34

CAN, as far as I am aware, usually refers to the strong oxidant ceric ammonium nitrate, which is not what you are looking for, I'd wager.

Hennig Brand - 15-10-2011 at 05:52

This is an interesting thread.

I have had the same problem lately that some of you have been having. I have been getting cold packs at the local Walmart for the last few years and it has always been pure enough to do nitrations directly. It wasn't perfectly pure however, since when dissolved in water and filtered a small amount of insoluble scummy material could be seen left on the filter paper. The mass of slightly moist AN from one of these packs, (each box contained two packs), was usually around 80g.

Here is a picture of some of prills which I just took out of one of the more recently bought cold packs. I think I bought them ~ 2 months ago.

I weighed the brown prills and found that there is now ~ 50% more material by weight in the new packs.

A few months before this last time I also bought some and they were nice and clean.

BTW, this new material foams up a lot when mixed with acid. Probably is CAN (calcium ammonium nitrate).

The packaging is identical to what it was before, as far as I can tell. The package says, "Contents; contains ammonium nitrate and water".

[Edited on 15-10-2011 by Hennig Brand]

Steve_hi - 15-10-2011 at 06:03

I bought 25kg of 27-0-0 fertilzer just mix with hot water simmer a bit then ladle off the shit that floats to the top let it sit for a few hours decant off the good stuff throw out the shit in the bottom let the good stuff set for a few more hours the ladle it out because some more stuff will have sedimented to the bottom put it in the freezer to crystalize out, vacuum out the water with vacuum filtration let it dry and you will have a lifetime supply for 20$

Hennig Brand - 15-10-2011 at 06:17

Sounds fairly straight forward and a lot cheaper than obtaining AN from cold packs. I actually still have enough 34-0-0 to do me for a while, but I still like to experiment with chemicals from different sources. Another bonus of the old/pure cold pack AN was that it was actually quite a bit purer than the fertilizer grade 34-0-0 I have.

Another thing I just noticed, the product code on the new cold packs do end with CAN and the old ones end with A. Someone else already mentioned this, I was just reiterating.

Hennig Brand - 22-10-2011 at 09:08

I have found that it is a trivial process to purify the cold pack AN. The picture below shows fairly pure AN obtained by dissolving the dirty CAN in water and filtering through two coffee filters. There was still a trace of fine dirt that got through, but very, very little.

As someone already mentioned for best results filtering through something like diatomaceous earth would work well. I have done this before when trying to get graphite out of a sodium chlorate solution, and it does a very good job of filtering out fine particulate.

The filtered AN solution was put in a glass bowl on top of a small electric crock pot which was nearly full of hot water.This set-up was used to evaporate most of the water from the AN solution over night. The slightly damp AN from the evaporator was then put in an oven at ~105-110C for an hour or so to get it almost perfectly dry.

Like others I also noticed that there was a slight ammonia smell when the CAN was in solution. This is just the ammonium and the base reacting (acid/base reaction) giving off ammonia. This is not big deal, at room temperature and with CaCO3 as the base the reaction is very slow.

[Edited on 22-10-2011 by Hennig Brand]

Steve_hi - 6-11-2011 at 20:28

Hi I watched a Youtube on how to make sodium nitrate using NaOH and NH4NO3 Mine didn't turn to liquid as shown on youtube by just mixing the 2 reagents so I added a little water as he said I could I heated it to dryness and it turned to a fine powder I mixed a little with sugar and lit it it burned with a yellow flame so I guess it worked somewhat. I am wondering when you react chemicals this way how pure is the product especialy since Im only using technical grade reagents so i would have sodium nitrate and ammonium hydroxide isnt the ammonium hydroxide still mixed in with the sdium nitrate? how do i seperate it? and I just want to be sure this whats called a double displacement reaction?

http://www.youtube.com/watch?v=bvVozS7A8io&list=WL3B901E...

cyanureeves - 7-11-2011 at 05:16

heat will drive off the amonia but if it still smells then you probably can get more nitrate out of it.

Steve_hi - 7-11-2011 at 06:18

Thanks cyanureeves
So if the ammonia is driven off by the heat that leaves the OH ion hydroxide does this also decompose or get driven off by heat and if so which one leaves first the OH or NH4

Rogeryermaw - 8-11-2011 at 14:53

in the reaction between ammonium nitrate and sodium hydroxide, if you use water to dissolve the chemicals, that water will absorb the released ammonia and the hydroxide ions will be consumed in the formation of water. this reaction, however, forms its own water so none is really necessary. just use patience. if you do not use water then the off gassing of ammonia will be much more energetic as there is much less available water to absorb it. one mole each of the nitrate and the hydroxide will yield one mole each of sodium nitrate (s), ammonia (g) and water (l).

NH4NO3 + NaOH -> NH3 + NaNO3 + H2

elementcollector1 - 25-3-2012 at 21:21

Any brands at Walgreens that sell the AN cold-packs? I remember seeing some there but they wouldn't say the contents on the package.

vmelkon - 13-6-2012 at 13:41

Quote: Originally posted by Acetic Acid

You paid 19.95 for 500 grams of NH4NO3. That's a pretty good deal. However, in instant cold packs a few weeks ago, I paid $5.29 for two instant cold packs. They look very pure and the contents were around 150 grams each.

You can buy as many as you want and you won't be questioned about it.

I bought this
http://paramedic-canada.com/premiers-soins/chaud-froid/insta...

from Walmart for 2.38$. It says "fertilizer ammonium nitrate" but it looks very clean and I dissolved in water ---looks crystal clear. I added some H2SO4, no precipitate so there are no Ca++ ions. It contains 137 g.

It is possible that your Walmart won't have it and I have seen other packs from the same company that had urea instead of NH4NO3.

violet sin - 25-9-2012 at 22:59

@ rogeryermaw not being a jerk but.. you are missing something in your equation there.... you have a NO3- and a OH- radicals adding to 4 oxygen on left & only NO3- and some lonely H2 for a total of 3 oxygen on the right...

on another note,.. seems like you could use the NH3 waste from the alkali hydroxide route to alkali nitrates, for feedstock gas in making HNO3. by catalytic decomp to NO2 and subsequent absorption, no? maybe runn through a CaCl2 scrubber or cold catch to dry it. but if you were into that kind of thing could be nice to start with NH4NO3 and double(theoretically) your nitrate content. I mean if you were trying to mess around to get NH3 to try your catalyst any how why not get some NaNO3 you could also use to make acid or play with as is. I haven't bought any KOH yet so thats why I said sodium salt. red devil lye is readily available to me

just a thought, I haven't made many posts yet. So I hope this was on topic enough

[Edited on 26-9-2012 by violet sin]

Rogeryermaw - 25-9-2012 at 23:48

no you are correct. one mole each of ammonium nitrate and sodium hydroxide yields one mole each of sodium nitrate, ammonia gas and water. think i just forgot to type the last "O" at the right end of the equation.

[Edited on 26-9-2012 by Rogeryermaw]