The DTA and TG analyses of clay and rock dust samples are shown in Fig. 4a and b. The endothermic peaks at around 459 °C, 580 °C, and 700 °C are attributed respectively to evolving dehydroxylation of illite clay, α → β quartz inversion, and CaCO3 decomposition. The effect of flux component such as K2O, Na2O and CaO can be seen when the clay started to have a reaction at around 700–900 °C. The total mass loss of clay sample was 13%. The DTA curve of rock dust (Fig. 4b) shows small endothermic effect at 577 °C due to the presence of quartz and weight of sample reduced by 1.5% when the temperature increased to about 700 °C.