We did have a Hackaday Prize entry a while back on improvements to the Haber process for producing ammonia, which curiously is the feedstock for commercial nitric acid production processes.

That's because it's synthetic, made by reacting ammonia with nitric acid, he says. Ammonium nitrate is made all over the world and is relatively cheap to buy. But storing it can be a problem ...

"Anhydrous" means "without water," making it different from aqueous ammonia, which is a solution of ammonia ... key component in the production of nitric acid, a precursor to many fertilizers ...