Advanced Technologies of Potash Fertiliser Production from Promising Raw Materials

Aims To propose a new method for producing ballast-free potash fertilisers from promising raw materials. Background Potash ores from Chelkar and Zhilyan deposits with huge reserves were not previously explored. In this study, promising previously unexplored potash ore deposits with huge reserves were examined. Chemical and mineralogical compositions of potassium rock from Chelkar and Zhilyan deposits were determined based on which carnallite nature of both salts was found. However, Chelkar salt also contains a large amount of impurities of sodium chloride and calcium sulphate, and Zhilyan salt is more concentrated in potassium, contains less halite and does not contain insoluble gypsum. For these salts, a method of incomplete dissolution for raw material enrichment in potassium was selected and validated. The process of subsequent processing of the enriched salt was investigated by means of nitric acid decomposition of this salt and two-stage crystallisation of target salts from the extract. Thermodynamic probability of the reactions’ occurrence confirms the formation of an equilibrium solution. We calculated the activation energy for the main reaction,which proves the inside-kinetic region of behavior. Objective To study kinetics and chemical equilibrium of nitric acid decomposition of potassium raw materials. Methods Processing of previously unexplored potash ores, IR, XRD, SEM, and spectrometric methods of analysis. Results Chemical and mineralogical compositions of potash rock from Chelkar and Zhilyan deposits were determined, and the main stages of their processing have been studied. Conclusion New effective methods for producing chlorine-free potassium and potassium-nitrogen fertilisers have been proposed, which are characterized by minimal water input and the absence of production waste. As a result, a method for producing ballast-free potash fertiliser was proposed, which was not previously used for other kinds of raw materials. This method allows us to not only enrich raw materials with the potash component, but also to separate an insoluble gypsum intergrown with other potash minerals in the ore composition. The use of traditional processing methods does not allow for obtaining a completely water-soluble fertiliser.