Non-isothermal kinetic studies of rubidium extraction from muscovite using a chlorination roasting-water leaching process

Rubidium in muscovite was selectively extracted using a chlorination roasting-water immersion method. The experimental results revealed that the chlorination effects of this metal were best when the roasting temperature was 800 °C. After 30 min of water immersion, the extraction rate of rubidium was the highest (96.71%), and XRD and SEM-EDS were used to analyze the migration transformation of elements and the phase changes that occurred during the chlorination roasting process. Finally, the non-isothermal kinetics of the muscovite chlorination roasting process was investigated via TG-DTA. The results revealed that the most probable mechanism for this process in non-isothermal conditions was the 3-D diffusion (Z-L-T) model with the integral form with g(a) = [(1-α)-1/3–1]2. The activation energy was determined to be 216.92 kJ·mol−1. Furthermore, the kinetic equation for fitting the results was formulated.