STUDY OF THE CAKING PROCESS OF THE NITROGEN-PHOSPHATE FERTILIZERS

Caking is one of the main reasons for the loss of quality of granular mineral fertilizers during storage and transportation. The mechanism of fertilizer caking is based on some cycles of its humidification-drying, leading first to the formation of a saturated solution between the particles, and then, when the sample dries, to the formation of solid salt bridges at the contact point. The paper presents an updated version of the method for determining caking based on GOST 21560.4-76. In order to simulate various conditions of fertilizer transportation (in sealed bags, so called big-bags, and for bulk transportation), two variants of test parameters were selected: in a drying cabinet and in a climate chamber. Ammophos, a granular nitrogen-phosphorous fertilizer, was selected as the object of the tests. The dependence of the absolute humidity in the intergranular space of the sample for each variant of the test is investigated. The dependence of caking on the test time was studied, it was shown that when tested in a climatic chamber, caking reaches its maximum values in about 4 hours. For the variant with holding in a climatic chamber, the dependence of caking on the load was studied. It was shown that the dependence has close to linear character. It was found that caking increases linearly with an increase in relative humidity in tested in the climatic chamber. For citation: Sokolov V.V., Kochetova I.M., Shestakov G.A., Mednikov I.S., Kolpakova N.V., Andrianova E.A. Study of the caking process of the nitrogen-phosphate fertilizers. ChemChemTech [Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol.]. 2025. V. 68. N 5. P. 49-55. DOI: 10.6060/ivkkt.20256805.9f.