Production of products with fertilizing properties by mechanochemical activation of phosphogypsum and Karatau phosphorite

Abstract

The long-term use of phosphorous deposits in the Karatau basin has led to depletion of reserves of rich ores containing P₂O₅. Therefore, obtaining the necessary materials by methods of enriching the composition of phosphorites in the presence of reagents is an urgent problem. The aim of the work is to obtain a product with fertilizing properties by mechanochemical activation of a mixture of phosphogypsum and phosphorite Karatau based on acid salt. Obtaining the required product by mechanical activation of phosphate raw materials is of great scientific and practical importance. Therefore, it is very important to study the patterns of changes in the production of products with fertilizing properties by mechanochemical activation in the presence of phosphogypsum and phosphorite Karatau and acid salt (Na₂SO₄). A mixture of phosphogypsum and Karatau phosphorite was modified with acid salt with different ball sizes and a 10:1 mass ratio of the ball and mixture (phosphogypsum-phosphorite Karatau-acid salt). To determine the phase composition of modified phosphogypsum in the presence of an acid salt (NaHSO₄) of Karatau phosphorite and identify the resulting product, methods of X-ray phase analysis (XRF), scanning electron microscope (SEM), and energy dispersive analysis (EMF) were used. It was found that the optimal conditions for obtaining a product with fertilizing properties obtained by mechanochemical activation (MHA) from the Phosphogypsum-Karatau Phosphorite-NaHSO₄ (3:6:1) system are 20-minute processing in a planetary mill: P₂O_5total=55%, P₂O_{5 lem. acid}=44%, P₂O_{5 cite. sol.},=82%. X-ray phase analysis showed that silicon dioxide, sodium-calcium hydroxophosphate carbonate, calcium hydrophosphate with bicolecular water and sodium-calcium sulfate with tricolecular water and calcium hydrophosphate (CaPO₃(OH)·2H₂O) fertilizer with bicolecular water were formed as the reaction product. Phosphogypsum-Karatau Phosphorite - NaHSO₄ system (3:6:1) due to solid-phase processes occurring as a result of 20-minute MOSS, the results of scanning electron microscopic analysis clearly show structural changes in the initial sample. The particle sizes range from 0.5 microns to 10 microns. As a result of energy-dispersed spectroscopic analysis, it was found that the content of elemental phosphorus is 4.97%, oxygen is 46.87%. That is, the product obtained in the environment undergoes some changes.