Synthesis of NPK fertilizer from low-grade phosphate raw material

Abstract

The article presents the results of studies of the process of obtaining NPK fertilizer from low-grade phosphate raw materials with P2O5 of about 18%. Phosphate raw materials were leached with a mixture of nitric-phosphoric acids with the addition of potassium carbonate, which serves as a source of potassium in the final product. The main parameters determined were the content of the main nutrients P2O5:N:K2O, temperature and time of the leaching process. According to the graphical method, the “apparent” activation energy of the heterogeneous process is found, which is equal to 3.8 kJ/mol indicates the intradiffusion nature of the process. Methods of chemical analysis, scanning electron microscopy and XRD analysis were used for a comprehensive study of raw materials and final products.

Modelling mineral reserve assessment using discrete kriging methods

“…Content of useful components within the prospected cross-sections is identified according to the analysis of placer samples [49], [50]. If content of useful components, identified owing to the prospected cross-sections, extends to neighbouring subsoil then errors of their assessment occur [51]- [53]. Linear interpolation errors results from the fact that spatial content variability inherits more complex laws.…”