The process of producing NP-fertilizers by nitric-sulfuric acid decomposition of phosphate rock (17.20% P2O5) under thickening slurry conditions has been studied. It was shown that the higher the recycle ratio, the lower the moisture content of the final product. Increasing the HNO3 dosage above 30% and H2SO4 above 70% is undesirable, as the product's moisture content exceeds 6.03% and it has increased acidity. To avoid issues during ammoniation, an optimal rate of nitric and sulfuric acid was proposed—73.5-91%, which produced products containing 9.34-10.61% -P2O5total; 3.04-4.54% N; P2O5 digestive:P2O5 total = 73.4-82.3%; pH = 3.3-3.6, and granule strength of 2.1-2.3 MPa. The process of producing NPK-fertilizers was also studied by adding nitrogen components such as K2SO4, KCl, and K2CO3 to the products of complete nitric acid decomposition of washed and dried concentrate (24.10% P2O5) and fine fractions (18.55% P2O5). The process includes decarbonization and decomposition of the phosphate raw material (simultaneously in one apparatus), neutralization to a pH not lower than 3.5, evaporation of the slurry to a density of at least 1750 kg/m3, the addition of potassium salts at N:P2O5:K2O ratios of 1:1:1, 1.5:1:1, and 1:1.5:1, product granulation, drying in the presence of recycle, and cooling.

Phosphorites of Central Kyzylkum and Karakalpakstan, inorganic salts, activation

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