Authors: M.M. Samadov, R.E. Azizov, F.V. Yusubov, Mammadova , S.G. Aliyeva, S.H. Javadova

Title of the article: Determination of phosphorus phase composition fertilizer produced by decomposition apatite concentrate with sulfuric acid in presence of intensifying additives

Year: 2024, Issue: 2, Pages: 14-23

Branch of knowledge: 2.6.7. Technology of inorganic substances

Index UDK: 661.632.2:631.841.1

DOI: 10.26730/1999-4125-2024-2-14-23

Abstract: The possibilities of improving the physicochemical properties of phosphorus fertilizer obtained using an intensifying additive, ammonium hydrogen sulfate, are being considered. The continuous progress of the chemical industry requires the creation of fundamentally new, more modern, economical and environmentally acceptable methods, as well as the intensification of existing classical processes for the production of mineral fertilizers. Therefore, carrying out theoretical and experimental research to develop highly efficient, resource-saving and environmentally friendly technological systems is one of the priorities of modern chemical technology and the relevance of solving these problems is beyond doubt. The purpose of this study is to determine the phase composition of phosphorus fertilizer obtained by the decomposition of fluorapatite with sulfuric acid in the presence of an NH4HSO4 solution and to determine the condition for increasing the solid phase in the reaction mass. Carrying out systematic theoretical and experimental studies of the process of decomposition of natural phosphates with sulfuric acid using the intensifying additive ammonium hydrosulfate and the processing of natural phosphates into phosphorus-containing fertilizers enriched with additional nutrients and the creation of new effective methods for producing mineral fertilizers seems to be a promising direction in the technology of mineral fertilizers. Determining the temperature and concentration conditions for the sulfuric acid decomposition of fluorapatite with sulfuric acid in the presence of ammonium hydrosulfate made it possible to clarify the features of the isolation and interconversion of calcium sulfate modifications. Based on experimental data on solubility in the CaO-P2O5-H2O system at a temperature of 100°C, a solubility diagram was constructed and the areas of crystallization of calcium and ammonium phosphates were determined. The optimal ratio of NH3:H3PO4, a slight increase in the mass of the solid phase and modification of the resulting product with an additional nutrient element - nitrogen, associated with the formation of ammonium dihydrogen phosphate crystals - were determined. It has been established that when choosing temperature and concentration conditions for sulfuric acid decomposition of natural phosphates in the presence of ammonium hydrogen sulfate, it is necessary to take into account the peculiarities of the release of crystals of calcium dihydrogen phosphates and ammonium dihydrogen phosphates into the solid phase, as well as the interconversion of modifications of calcium sulfate.

Key words: phosphorus fertilizers intensifying additives phase composition solubility isotherm nutritional elements

Receiving date: 01.01.1970

Approval date: 15.06.2024

Publication date: 01.01.1970

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