Study of Structural Transformation and Chemical Reactivity of Kaolinite-Based High Ash Slime during Calcination

The transformation of kaolinite into metakaolinite by thermal activation to obtain highly active aluminosilicate is commonly known. In addition kaolin, the high content in coal mining waste another potential source for obtaining an precursor, thereby protecting environment and adding value industrial wastes. this paper, kaolinite-based ash slime (KAS) was calcined at temperatures ranging from 400 °C 1000 under air, N2, CO2 atmospheres, respectively. behaviors structural evolution each component KAS were analyzed analysis (TG-DSC), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), photoelectron (XPS). Moreover, chemical reactivity Al2O3 SiO2 evaluated HCl NaOH leaching methods. results show that applied study primarily consisted carbon, while minor mineral phases included quartz, calcite, pyrite. Additionally, during calcination dehydroxylation, sintering, formation mullite. Crystalline completely decomposed semicrystalline 600–800 °C, accounting increase reactivity. interlayer sintering recrystallization amorphous components led decrease after 800 °C. Furthermore, carbon are greatly affected atmosphere. presence reduced KAS.