Investigation of Morphology and Composition of the Mineral Fertilizer Granules with Nanostructured Areas

The study of morphology, crystal structure, and elemental composition of controlled-release capsulated mineral fertilizers with nanoporous structure was provided in this work. Four types of fertilizers with nitrogen-containing core and phosphate-containing shell were proposed and analyzed. Various types of plasticizers were used for granulation. Cross-section of granule shelles and the interfaces between thee shell and core were analyzed. Samples with multiple types of core-shell were compared. The quality of nanoporous surface, the presence of shell defects, and features of the interface, particularly the quality of superphosphate shell attachment to carbamide core, were estimated. The presence of small nano-pores along the shell surface makes it possible to reduce the rate of dissolution of the fertilizer in the soil, create fertilizers with prolonged action and increase the uniformity of fertilizer, as well as to control the dissolution time by varying the shell thickness and the relative number of nanopores in the granule shell.