Thermochemical and Experimental Kinetic Analysis of Potassium Extraction from Ultrapotassic Syenite Using Molten Chloride Salts

Abstract

This paper reports on the application of molten chloride salts, NaCl and CaCl₂, for extraction of potassium from Oxley rock (ultrapotassic microsyenite) mined in Western Australia based on both experimental kinetic and thermochemical analysis. The reaction parameters of temperature, time, and salt to ore ratio were systematically analyzed, and a potassium extraction of more than 90% and 87% using CaCl₂ and NaCl, respectively, was obtained. In this paper, thermochemical equilibrium models have also been developed which show excellent agreement with experimental data and also allow one to predict how the system deviates from equilibrium where the maximum potassium extraction can be obtained. Also, this study offers a potential comparison between the use of NaCl and CaCl₂ in terms of potassium extraction and reaction mechanism. Different mineralogical studies have been conducted to characterize the ore and also to understand the reaction principle of the ore with NaCl and CaCl₂.