Thermal activation and alkali dissolution of silicon from illite

Abstract. TGA, DTA, FTIR, XRD and 29Si MAS NMR were used to investigate the thermal activation of illite. Illite experiences a series of thermal solid-state phase transformations. Dehydroxylation at 400∼700 °C forms dehydrated illite, which remains the layered framework of illite. From 700 °C to 1093 °C, Si–O tetrahedral framework remains unchanged. When heated above 1093 °C, the layer…