Hydrodynamic and Thermodynamic Conditions for Obtaining a Nanoporous Structure of Ammonium Nitrate Granules in Vortex Granulators

Abstract

The formation of the developed nanoporous structure on the surface and inside granules of customary ammonium nitrate, which is used as mineral fertilizers, expands the areas of its application due to the peculiar properties obtained. Single- and multilayer granules of porous ammonium nitrate (PAN) are used as a main component of the industrial explosive ANFO. Ammonium nitrate granules with a nanoporous organic membrane are successfully applied in agriculture. This paper presents the results of theoretical and experimental studies on the determination of the optimal hydro- and thermodynamic conditions for obtaining the PAN granules, including multilayer ones, in a vortex granulator. The nature and the configuration of pores depend on the type of the moisturizer, and hydro- and thermodynamic conditions for dehydration when PAN granules are produced in the fluidized vortex granulators. The studies conducted prove the influence of the thermal processing, the hydrodynamic regime of the apparatus, and its construction peculiarities (the workspace configuration, the way of creating the vortex motion of granules, etc.) on the qualitative and quantitative composition of PAN pores. The developed nanostructure surface of PAN granules (composed by micro-, meso-, and macropores) leads to the bigger amount of diesel fuel penetrated and bound while producing the ANFO. This brings better detonating and destructive properties of the explosives. The optimal hydrodynamic and thermodynamic conditions for obtaining a nanoporous structure of ammonium nitrate granules were determined.