DEVELOPMENT OF TECHNOLOGY FOR PROCESSING THE CHELKAR DEPOSIT ORE INTO POTASSIUM FERTILIZERS

Abstract

Kazakhstan possesses significant reserves of potash ores located in the Caspian lowland. Chelkar deposit is one of the largest deposits. It is characterized by carnallite mineral content in the composition, which can serve as raw materials for potash fertilizer production. However, nowadays such production is absent, and the technology for obtaining potassium salts from domestic raw materials has not been also developed. At the same time, the agricultural demand for potash fertilizers is extremely high, which are still imported from Russia and Belarus. In this regard, we carried out a set of studies of Chelkar ore composition and methods of enrichment and processing this raw material to obtain chlorine-free water-soluble potassium and complex mineral fertilizers. The article presents the research results of processing washed potash ore.  Optimal enrichment mode was determined using the mother liquor to achieve natural salt maximum washing degree from sodium. The process of nitric acid decomposition of concentrated ore at a temperature of 50°C has been studied. Kinetics of ore decomposition has been preliminary studied. The optimal time for reaching equilibrium equal to 30 minutes and nitric acid concentration equal to 20% was established. To ensure high suspension filtration rate the washed non-calcined ore should be used. Mineral potassium-magnesium sulfate fertilizers were obtained by crystallization from nitric acid solution by a isothermal method and by drying the ammoniated solution. The developed technology is patented by a useful model "Method for processing potash ores to obtain potassium sulfate".