Technology for production of granular calcium-ammonium nitrate

Abstract

The article presents the technology for production of granular calcium-ammonium nitrate, which is suitable for implementation into the existing production of complex mineral fertilizers. The paper considers the physicochemical foundations of manufacturing calcium-ammonium nitrate and provides the calculations of the equilibrium constants of the reactions occurring at the temperatures of 25–1700С. A new process flow diagram was proposed. It was shown that the production of calcium ammonium nitrate as a valuable agrochemical fertilizer is possible by mixing of 82–84% ammonium nitrate solution with solid carbonate raw materials with further granulation and drying in a drum granulator and dryer. The work determines the conditions for the interaction of reagents making it possible to reduce the losses of nitrogen. The density of aqueous suspensions of chalk and the rate of its precipitation are established. The obtained results allow improving an industrial plant based on the existing equipment for the production of complex mineral fertilizers. The technological parameters for the preparation of the product are optimized to meet the requirements of technical conditions. During commissioning and stabilization of the technological regime, a product was obtained containing 25.9–27.8% of total nitrogen, 15.6–16.8% of CaCO3, 0.01–0.64% of Ca(NO3)2, and 0.32–0.75% of H2O with the following particle size distribution: 95.3–96.3% of 1–5 mm particle size, and 3.7–4.8% of particle size of less than 1 mm with a granule hardness of 30 N per granule.