RESEARCH OF THE PROCESS OF PRODUCING POTASSIUM SULFATE THERMOPHOSPHATES

Thermal phosphates play an important role in agronomy, especially in the context of improving soil quality and increasing the availability of phosphorus for plants. The process of sintering natural phosphates with alkalis allows to obtain fertilizers that have high digestibility and can be effectively used on acidic soils, which is an important aspect for agriculture in regions with similar conditions. In addition, the effect on the soil, similar to liming, emphasizes the versatility of these products. This makes them especially valuable for sustainable agriculture, where it is important not only to provide plants with nutrients, but also to maintain soil fertility. Traditionally, Na2CO3 or Na2SO4 is used to obtain thermal phosphate. During the decomposition of apatite with sodium sulfate, sulfate is reduced to sulfide, which then reacts with apatite, forming sodium phosphate and other products. This indicates the complexity of the process and the need to control the reaction conditions. For the efficient production of thermal phosphate, it is important to correctly calculate the ratio of components such as phosphorite (apatite), modifying additive and coal. Optimal proportions can significantly affect the yield of the final product. The process of obtaining thermal phosphates from natural phosphates such as apatite is a complex technological chain including heat treatment, chemical reactions and subsequent processing. Analytical studies of the feedstock and processed products were carried out using a desktop X-ray spectrometer to determine the elemental composition, the assimilable form of phosphorus was determined photometrically. In this work, phosphate limestone, potassium sulfate and activated carbon were used as feedstock. Apatite, which is part of phosphate limestone, has a unique structure and is in the form of finely disseminated and dispersed mineral. In this work, sulfate-potassium thermal phosphates were synthesized at a firing temperature of 10500, exposure time of 1 hour. The following optimal ratio was chosen: phosphorite: potassium sulfate: coal = 1:0.5:1. The content of total P2O5 = 3.47%, digestible form P2O5 = 1.07%. Further studies will be aimed at obtaining a rough concentrate with testing for obtaining thermal phosphates, thermal phosphoric acid, ammophos, precipitate. Thermal phosphates can be used on all types of soils and show good efficiency, especially on acidic podzolic soils. However, on chernozems and sierozems their efficiency may be lower compared to superphosphates. The digestibility of thermal phosphates depends on the fineness of grinding, and the most effective fraction is with a particle size of 0.075-0.105 mm.