Ammonium nitrate contamination

[max6333]

I was going for my first batch of AN from CAN and I dissolved a lot of it in boiling water but when I went to filtrate it, it just went trough the filter(i tried filterpaper,coffefilters,socks,kitchen towells) so the dust in it stayed and the ammonium nitrate crystalized out ( i didn't cool it so only a part of it crystalized) Now what i need help with is cleaning it, avoiding it getting dirty next time . (decantation is the only process how i succesfully got rid of the dust but cant do that because it cools and crystalizes)

[Differential]

By CAN, do you mean calcium ammonium nitrate, or calcium nitrate? If you add more water, the insoluble stuff will eventually precipitate without the AN crystallizing. If there's some Ca(NO3)2 still in solution, maybe try adding some ammonia solution - AN will stay soluble, and the calcium hydroxide formed will settle out. The nice thing about ammonia is, if you add too much, it still boils off.

 

Lab filter paper has the finest pores, and there are different grades available. If that doesn't work, coffee filters, socks, etc won't work - with the possible exception of high thread count pillow cases.

Edited February 10, 2015 by Differential

[FlaMtnBkr]

I assume he meant the non soluble contaminants were fine enough that it went through his filter material?

 

Since you want to filter it fast to keep it from cooling much and coming out of solution I'm not sure what the best process would be? The finer the filter the slower the flow rate for the same size filter area. Maybe multiple layers of filter material and vacuum filtering?

 

I can imagine a way to do it but without knowing the process and amount of particulate I don't want to mention it because it isn't common lab procedure and could be potentially dangerous.

[Differential]

For very fine particles, adding some chitin or bentonite slurry might help them settle faster. Works for wine, anyway. Or maybe a natural polymer - like lightly beaten egg whites, or gelatin. Egg whites were used in the old days to make coffee grounds settle if you didn't have a filter.

[Mumbles]

The ammonium hydroxide and calcium nitrate reaction is reversible, so it may not be the best route. The conditions which make calcium hydroxide easier to filter also tend to make the reaction go in reverse. You'd probably be better off finding ammonium sulfate.

 

Is there any reason you can't dissolve the CAN in room temperature water and filter/decant? From there with your particulate free solution you can go about doing your crystallization. You could also just filter into a hot container, or re-heat the filtrate.

 

Along the same lines as what Differential brought up, some filter aids could help. Celite or sand are common, and tend to have decent flow rates. One other trick is to just heat the solution up, let the dust settle, and allow it to crystallize as-is. From there you can suspend the dust or fine particulates with a non-solvent and flush them away. You wont get analytical purity product, but you're not exactly doing precise chemistry here anyway.

[pyrojig]

Mumbles that is a very well described process

 

. A-Sulfate is the better and cheaper salt to use for the double exchange. Working at rm temps is the key . One could let the solids settle , decant , then dry the cleaned up AN. OR, as Mumbles said, boil and let it crystallize in solution , as crystallization is a natural way of purifying . The clay and other crap should not get trapped in the crystals of AN as they form . It is very hard to remove all the CaNo3 out of the AN, as they share very similar qualities and like to host together . If the final salt is for gen. chemistry , it should be ok, and will work just fine for reactive targets . Too much trouble IMO to get a "cleaner " product. Unless you have lots of space and time to work with , it is not a enjoyable adventure.( unless your only after small amounts )

[mabuse00]

You do not need boiling water.

 

Just look how much nitrate your fertilizer should contain and dissolve the stuff in the according amount of tap water.

Stir it until all prills are broken into mush.

And then let it settle, a few days or even a hole week.

 

Ideally use an XXL version of this, or something with a similar shape - high and slim.

http://www.glasslaboratory.com/files/2245127/uploaded/GL-T25-1000%20Measuring%20Cylinder.jpg

 

Then you usually have a dirty layer on top and sludge at the bottom - and a crystal clear solution in between.

What I usually do is to take a hose and siphon the crystal clear brine away.

 

Now if you want high quality stuff, you can still filter that brine, I think celite is your best friend here.

 

 

Try not to stirr up anything from the ground. This stuff clogs your filter in no time and also IS very hard to filter out.

The foamy stuff from the layer on top is not so bad, it can be filtered out successful by a coffee filter.

[max6333]

There is no calcium nitrate in the CAN, at least thats what the previous threads i found say, the only problem is calcium and magnesium carbonate. It is to small and no filters can stop it(i tried egg whites , super small filters ... thats stuff just wont stay away) Question about the tap water solituion: Wouldnt I get much less of the AN out of it?( like 70%?)What Im gonna try is dissolving it in boiling water so that it can stay in solution after cooling down and then boiling down a part of it

Edited February 11, 2015 by max6333

[Mumbles]

Depends on the variety of CAN. Some has actual calcium nitrate. Some has carbonates. If you're boiling the carbonate stuff, you're going to be making calcium nitrate though. It should be easy to differentiate. One will have traces of insoluble material, the other will have 20 or 30%. Threads are meaningless when they don't reflect reality.

[max6333]

The guys who make the list of stuff the fertilizers contains dont know shi*, they say 13% nitrogen 13% ammonia (so i concluded 26% ammonium nitrate) there is no other nitrate mentioned.The dust is dolomite MgO CaO. On some other sheet its says its 27% nitrogen and now i know that nitrogen is actually AN because there is a second fertilizer that is 30% nitrogen but its called AN 30% so now i know nitrogen means AN (Unless its some other NO3 but I know kan is not because it says that the calcium is all in oxides)

Edited February 11, 2015 by max6333

[Arthur]

Due to the use of Ammonium Nitrate by people with adverse intent, additives are being put in deliberately to deter people making ANFO. Even the prill hardness now means that fertiliser grade doesn't take up oil as well as explosive grade.

 

Be very careful when using quoted mineral content. Read how the content is assayed and then quoted. For example KNO3 is assayed for Potassium as K20. But there is no actual K2O in there, it's how it's determined chemically

[max6333]

Since this fertilizer is made in my country not outside it I think they wouldnt mess me up because most explosives are legal here.No terrorism going on here.I am pretty sure that mine is pure AN because I've seen a few posts from people of my country saying that Can(we say KAN) is the best (idk why ,there are much bigger percentage fertillizers, maybe its the purest) And they have their guides wich are badly described and involve stinking your house up with ammonia

[Arthur]

Your country may be free of terrorism, but any source of AN will get used by terrorists anywhere. These changes to AN to ease it's use in fertiliser and make it's use in terrorism tend to be globally introduced under the auspices of the UN.

[max6333]

Got some more problems with drying it.When I put it in the oven on 120 C to dry it it all dissolves ass the temeprature is high again , and then its just basicly boiling it off slowly.(also why dont people just boil it off... whats up with all the crystalization)Another problem is that the water freezes when I go to cool it so I cant seperate the water and the crystalls(thats kinda my drying problem too , if i could mostly seperate it it would prolly be fine)

[FlaMtnBkr]

Dry it at a cooler temperature? Does the water vapor have a place to get vented out once it evaporates?

 

I think people crystallize it at a low temperature to help purify it. The other contaminants stay in solution and mostly AN comes out of solution so they can be separated.

 

Edit: instead of trying to freeze it, put it in an ice bath so you can get it right above freezing.

Edited February 12, 2015 by FlaMtnBkr

[max6333]

thanks for the tips, there is one weird thing going on tho, when I boil it so that crystals for on the sruface a bit and then cool it there is no water left... did the AN suck it up or what? Also when i get them out of solution they are fully wet right(after they crystalize)(by fully wet i mean they have sucked up all the water they can with their hygroscopiness) so drying them is nessisary ?Also how to know when they are fully dry?

[FlaMtnBkr]

I'm not sure I know exactly what you are asking but you will know when it's dry or if it has started to absorb water.

 

When it is dry it is nice and crunchy and it flows easily and breaks apart. When it starts to absorb water it loses that dry crunch and starts to stick together. It will keep doing this until it obviously has water in it and looks moist and eventually will turn into a puddle where it absorbs so much water it all dissolves into solution. You will be able to tell when it is dry once you mess with it some

 

You can also weigh it until it stops losing weight to know when it is completely dry.

[celia1095]

Anyone know this ?

How to protect concrete surfaces from corrosive attack of CAN fertilizer (calcium ammonium nitrate)?

When CAN absorbs moisture from atmosphere, it becomes extremely corrosive for concrete.

My mail: celia1095@qq.com

[OldMarine]

A good concrete sealant is the only option I can think of. The Thompson's products have served me well protecting concrete and aggregate over the years. There were no caustic or acid chems involved though.

[celia1095]

realized, thanks so much.