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

摘要

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 degrees 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 (alpha) = [(1-alpha)(-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. (C) 2020 Published by Elsevier B.V.