STABILIZED CAMMONIUM NITRATE AND PREPARATION THEREOF

1309612 Stabilized ammonium nitrate CHEMICAL CONSTRUCTION CORP 11 Jan 1971 [22 Jan 1970] 1317/71 Heading C1A Solid, particulate ammonium nitrate is stabilized against thermal shock at phase transition temperatures (e.g. 32‹ and 83‹ C.) by incorporating into the molten nitrate a small amount of a silicofluoride, a phosphate and a sulphate and solidifying said melt. The molten nitrate may contain up to about 5% wt. of water. Preferred silicofluorides are Na, K, Mg, Zn or NH 4 , preferred sulphates are NH 4 , Na, K or Ca and preferred phosphates are monoammonium, diammonium or trisodium and the preferred amount of each additive is up to 0À5 wt. per cent. The phosphate and sulphate may be added to the molten nitrate, or its precursor nitric acid, as phosphoric acid and sulphuric acid during production of NH 4 NO 3 and neutralized by addition of a base, e.g. NH 3 , NaOH, Na 2 CO 3 , KOH or K 2 CO 3 , in situ. The preferred method of solidifying the product is to spray it into an air stream.