Preparation of Ammonium nitrate

[Desmikes]

Do you have to purify ammonium nitrate from 34-0-0 fertilizer in order to use it for ANFO? If so how long do you have to “bake” it after most of the water that was used for dissolving NH4NO3 was boiled off? I had it in the oven for about 4 hrs (220*F/115*C) and it still seemed damp. Is it possible to just let diesel + AN (in pellet or powder form) mixture sit for couple of days instead?

[kingspaz]

34-0-0 is greater than 90% ammonium nitrate which means you don't have to purify it. its the NPK system standing for nitrogen, phosphourous and potassium. the numbering shows it has no K or P in it only N which means it must be ammonium nitrate.

[Anthony]

Just heat it until its dry. The powder will often form a weak, crumbly cake. If you can brak up a piece and rub/crush it into powder with your fingers, it's plenty good to go.

[jfk]

ok, sorry to bring this thread back again, but i was just doing a search for one of your replies Anthony about AN Prills. i got mine from a hydroponics store - how should i go aobut pre paring them?

im only makin a small ammount of MEKP-AN would just grindin them up be suitable or would i have to wash them and oven dry them? (if so how shoudl i go about it>?)

[GibboNet]

I know you asked for anthony's help with this, but I'll give it a go, mostly because I want it to be confirmed for my own knowledge.

Firstly, it probably wouldn't matter which way you went about it, as long as your AN ended up dry. crushing it 'as is' means less fuss and bother with drying, which can be very time consuming. Dissolving and recrystalising it can be a pain in the messines, depending on how careful you are, but it can be a lot easier on the arms if you are thinking of hand crushing it, as the prills will reform as crystals after driving the water off them.

You don't need to go either way - whatever is easiest for you, because the result is the same both ways, assuming you do it correctly.

I used some AN from cold packs not that long ago, but in transporting them home in my backpack, the water packs in one (got two brands to see how much in each) had burst . At the time, (living with parents etc.) I had no way of oven drying it, so I simply put it in a wide glass jar, placed flyscreen over the top and left it in hot sun, taking it in and re-sealing it at night. after a couple of days I was left with the finest needle crystals on top of a cake of dried AN, which was crumbly to the touch, and powdered easily.

I have never got pure AN as prills, but if they are anything like other fertiliser prills, then they are very hard, coated, and would be very difficult to crush.

hope that helps.

EDIT: Desmikes says it can be placed in the oven for 4 hours at 115 degrees celcius, so I would reckon you could leave it in longer if need be. just check it regularly and move it around a bit to make sure it's getting dried evenly.

[Anthony]

Unless you're using the AN for a sensitive mix such as ANNM, where absolute dryness isn't critical, the AN will need to be dried after crushing.

Even being careful and crushing a little at a time, and placing the powder into a a sealed container the AN abosrbs moisture, leaving the finished powder damp to the touch. An hour in the oven at 100-120*C after powdering gives a nice bone dry product.

Crushing AN prills is a bitch, they're pretty hard and often fly out of the mortar. I usually watch TV whilst grinding. I can't do more than 200gm a day with my little mortar and pestle before my hands get sore.

Wetting and drying the prills befor crushing should make them easier to grind, but it's an extra step in the process.

[jfk]

i reckon these prills i got are a bit damp at the moment, they crush easy as.

i just finished my MEKP synth and got the AN ground it up shoved it in the oven @300 degrees for like 15 min.

all dry and crumbly now. gonna make some MEKP/AN soon, in a few hours when my HTMD cap synth is done

[Argy]

Personally i didn't succeeded to detonate ANFO made with 34-0-0 fertilizer with 40-50grams of AP... but i think it's clearly possible with a good booster (PETN / RDX for exemple)

[xyz]

You need several hundred grams of APAN to detonate ANFO, 50g of AP won't work

[Arthis]

Please not again on detonating ANFO here. There are endless threads about that.

Maybe a microwave would be enough to dry AN... in case you need some very fast.

jfk, your AN pills are easy to crush once dry ? Because when not dry it's pretty hard (you need a mixer, and I fucked my coffee crusher due to the AN humidity :( )

[Arthis]

Hey, you know the joke of the guy who wants to dry AN and put it in the oven at 220-230°C ?

I remember having read somewhere to let it at 300°C

I know this is stupid, but what can I do about it ? Think I'm gonna give HED myself... ;)