Creation of Granular Composite Materials With Multilayer Structure

Abstract

Granular products are widely used in many industries for the production of catalysts in oil refining and organic synthesis, drugs, food products, fertilizer production, etc. The main advantages of granular products are ease of operation and storage. Depending on the morphological structure, the granules obtained as a result of the technological process are divided into one-component, single-layer, composite-coated granule, multilayer granule, frame granule, and combinations thereof. In this paper, we consider, as an example, the technological basis of granulation of aqueous solutions of ammonium sulfate with impurities of humates, calcium carbonate and other substances with the formation of multilayer composite granules in a fluidized bed granulator. The processes of dehydration and mass crystallization during granulation, namely the influence of the drying rate and impurities on the kinetics of the evaporation process of the dispersed heterogeneous solution on solid particles have been studied. In the process of mass crystallization, when the saturation concentration is reached by removing the solvent, the processes of nucleation and crystal growth occur with the formation of a crystalline framework of ammonium sulfate crystals between, which impurities of organic matter and other components are evenly distributed in the volume of the formed micro layer. It was confirmed that the obtained granules of the composite granular fertilizer have a composite multilayer structure with a uniform distribution of suspended particles in the volume of the granule. Bibl. 14, Fig. 4.