Experimental kinetic analysis of potassium extraction from ultrapotassic syenite using NaCl–CaCl₂ salt mixture

This kinetic experimental analysis reports on the application of a eutectic NaCl–CaCl2 salt system for the extraction of potassium from ultrapotassic microsyenite. The reaction parameters, time, temperature, salt composition, and salt to ore ratio, were systematically analyzed. It was found that a salt mixture increases the potassium cation extraction in comparison with using either pure NaCl or pure CaCl2. It was also found that adding CaCl2 into pure NaCl has a considerably stronger effect on increasing the potassium recovery than adding NaCl to pure CaCl2. The salt as a melting agent offers a reduction in the reaction temperature due to its lower melting temperature when compared to pure salts (NaCl or CaCl2). Approximately 70% of K+ in the deposit was extracted at 650 °C. Different characteristic methods have been used to understand the reaction mechanism of the salt mixture and ore, as well as to qualify and quantify the end product mineral phases.