Making Fertilizer Less Explosive

Chemical company Honeywell makes enough ammonium sulfate each day to fill 50 railcars. Annually, that adds up to 190 million tons of the salt, which is a by-product of the company's caprolactam synthesis. With so much ammonium sulfate, Honeywell is always on the lookout for new ways to use the stuff. The company recently announced that it has developed a process to combine ammonium sulfate with ammonium nitrate to make a fertilizer that has significantly lower potential to be explosive than pure ammonium nitrate fertilizer, an attribute that would make it safer for farmers and potentially thwart terrorists. Ammonium sulfate nitrate fertilizers have been around for more than 100 years, but the Honeywell process makes a fertilizer that's far more homogenous, and therefore less explosive, than previous preparations. The fertilizer, known as Sulf-N 26, is described in U.S. patent 6,689,181. Invented by Honeywell scientists Ronald E. Highsmith, James A. Kweeder, and Steven T. Correale, it's a mix of (NH₄)₂SO₄, the double salts (NH₄)₂SO₄•2(NH₄NO₃) and (NH₄)₂SO₄•3(NH₄NO₃), and a trace of NH₄NO₃. Agronomic tests show that the material works just as well as conventional ammonium nitrate or ammonium sulfate fertilizers.