Dissolution Behaviors of Trace Muscovite during Pressure Leaching of Hydrothermal Vein Quartz Using H2SO4 and NH4Cl as Leaching Agents

Dissolution behaviors of trace muscovite during pressure leaching of hydrothermal vein quartz using H2SO4 and NH4Cl as leaching agents have been studied by means of optical and electronic microscopes. Phase transformations of pure muscovite during calcination and the pressure leaching were analyzed by powder X-ray diffraction (XRD) and thermal analysis (TG-DSC), which are used for indirectly discussing dissolution mechanisms of the trace muscovite. Structure damages of trace muscovite are caused by calcination, and further developed during pressure leaching of the quartz sand using H2SO4 and NH4Cl as leaching agents. The trace muscovite is dissolved, and then efficiently separated from quartz sand by coupling effects of calcination and fluorine-free pressure leaching.