It is made synthetically by the oxidation of nitrogen from air, and also by the creation of the ammonia from air, and combining the two to make ammonium nitrate.

Since all ingredients come from air, there is no contamination in the product.

The 100% ammonium nitrate is typically made into little spheres, called prills, a bit smaller than a BB. These are then coated with something to reduce their ability to absorb moisture from the air.

Typical coatings are clay, wax, etc.

The prilled stuff in sacks is usually about 95% pure. The added coating does not hinder its use enough to worry about.

If you want to purify it to 100%, dissolve it and recrystalize it from solution.

The labor wasted doing this is not a good use of your time or effort.

What you want to ask for is prilled ammonium nitrate, 34 0 0 fertilizer.

It comes in 50 pound clear plastic bags usuallty with a flap on one corner that makes a pouring spout when unflapped.

It can be dried easily by laying a thin layer in sunlight for a hour or so, when the air humidity is below about 70% or so. When warmed it changes crystal type, and expands. when cool it contracts to a different crystal type. this change takes place around 85 F or so. (trying to remember all this). This change at normal environmental temps causes it to be hazardous to use in solid fuel boosters, for the packed fuel can crack, which will raise the burning rate enough to explode the booster. Since you can't easily tell if someone exposed it to +85 F somewhere since it was made, it becomes a bit risky to use such boosters.

The sensitivity of AN to initiation is considerably easier when its above that 85 F temp.

As you heat it even higher it gets easier to initiate.

In fires where it is molten, if flames break out that raise the pressure of the container above about 200 psi, it will initiate into detonation. This pressure only has to be present for a small fraction of a second, like in a localized "Puff off" for the initiation to begin, and once the detonation wave is created it will take along with it all other AN around it, and unless the amount is small, like in a half inch pipe or so, that wave will go till it consumes all that is present.

About drying it in a microwave...
The outside will appear cold, while the center melts, and this is NOT good. You could ruin the microwave if it decided to initiate. This is especially bad if the stuff is at all dirty with any combustible.

Don't use the microwave, nor even the oven. Choose a sunny day, and sun dry it, with a stir every now and then, and then pack it in a air tight container. Those little cobalt chloride moisture indicators that come in silics gell and turn blue when dry and pink with moist can be used to monitor its condition when stored.

It is hard to grind when dry for it is quite hard then. Above 85 F and dry it is easier to grind due to the crystal change. Best to grind it slightly moist, (very slightly moist) and then dry the powder. Let it exposed to air, and try grinding it and when its got enough moisture it will begin to grind much more easily. Dry the ground stuff in small batches, for it tends to cake up easily in larger batches. It must be stirred as it drys or it will cake.

posted January 04, 2000 08:11 AM            

Have a fine mesh strainer ready, pull out the stopper and jam the mouth of the bottle against the strainer. As the water drains out, it carries away the sludge and the prills stay in the bottle 'cause they're too big to fit through the strainer.

Dump the wet prills into a pyrex dish big enough to hold all of it. Something with a lot of surface area like a cake pan is best. Toss it into an oven set at 250 degrees F. Then check on it every 30 minutes to stir it up till it has crumbled into a flour fine powder. Pour immediately into a jar and cap while still hot.

AN is more sensitive to initiation while hot, but it needs something to initate it. I've made Nitrous Oxide from fertilizer AN that I've processed as described above. That involves heating it to 500 F and it didn't blow up.

Its known that if you take AN made slightly moist with water and pack it into a container (think pipe), you can make the AN much more sensitive to detonation by thermally cycling it with an oven. You put the container in an oven warmed at about 140 F for long enough for the contents to warm above 34 C (whatever that is in F) for 10 minutes. You then take it out and let it cool below 34 C, and then back into the oven. You repeat this process a few time.

What this does is generate microscopic air gaps in the AN crystals (cause by their changing crystal shape) that greatly increases the sensitivity. And sensitizers like NM can flow into these microgaps and be much more intimatly mixed with the AN resulting in greater performance.

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"The knowledge that they fear is a weapon to be used against them." www.50megs.com/nbk2000

posted January 04, 2000 07:04 PM            

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"The knowledge that they fear is a weapon to be used against them." www.50megs.com/nbk2000

posted January 05, 2000 02:11 PM            

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"The knowledge that they fear is a weapon to be used against them." www.50megs.com/nbk2000