Technology for production of granular porous ammonium nitrate

The physicochemical principles of the process were considered and a new technology for the production of granular porous ammonium nitrate was developed that is suitable for integration into the existing production of complex mineral fertilizers. The methods for preparation of porous ammonium nitrate were proposed and the effect of various additives on the strength of granules was investigated. The dependence of the sorption capacity of brand B ammonium nitrate granules, which contains 0.3–1.0% H2O, on the number of heating and cooling cycles was been studied. It was established that when the granules are heated to 1300C and cooled to 300C, the required liquid fuel sorption capacity, equal to at least 10 g/100 g, can be achieved in two heating and cooling cycles. When heating the granules to 900C and cooling to 300C, five heating and cooling cycles are required to achieve the same value of sorption capacity. The technology and the proposed flow diagram of fabricating granular porous ammonium nitrate based on the existing equipment for the production of complex mineral fertilizers was developed. The parameters of the process of obtaining a product that meets the requirements of the technical conditions were optimized. It was shown that the production of porous ammonium nitrate is possible by mixing an 82–84% solution of ammonium nitrate with phosphogypsum followed by granulation and drying in a drum granulator-dryer, classification and heat treatment of granules with a size of 1–3 mm. To obtain strong granules, sulfate-phosphate additives are introduced into the ammonium nitrate solution, the source of which is phosphogypsum, a waste product from the production of orthophosphoric acid. The suggested use of a two-section mixer for carrying out the interaction of an ammonium nitrate solution with phosphogypsum ensures the minimum mixing time of the reagents.