Multilayer modified NH4NO3 granules with 3D nanoporous structure: Effect of the heat treatment regime on the structure of macro- and mezopores

The article is devoted to the investigation of the structure of macro- and mesopores on the surface and inside of modified NH
₄
NO
₃
granules. The main quality indicators of modified NH
₄
NO
₃
granules are presented and the relationship between the nanoporous structure of granules and the quality indicators is shown. Various thermodynamic conditions for obtaining a nanoporous structure of the surface and internal layers during the modification of granules are considered. The optimal regime for the uniformity of the temperature distribution in the vortex granulator is the regime of mixed motion of the drying agent. In this mode, mainly “modification” pores are formed, “mechanical” pores due to the absence of local overheating are practically absent. The nanoporous structure of multilayer granules, which are obtained using various types of humidifiers under the optimal thermodynamic mode of operation of the vortex granulator, is investigated. The results of the research make it possible to develop mechanisms for controlling the structure of granules during their modification due to the optimal selection of the humidifier. By varying the composition of the humectant in the production of multilayer granules, it is possible to achieve formation of mesopores inside the granule and macropores on its surface. This will allow the diesel fuel to easily penetrate into the granule volume and effectively stay there.