Eco-friendly treatment of coal gangue for its utilization as supplementary cementitious materials

Using coal gangue (CG) as supplementary cementitious materials (SCMs) is believed to be one of the effective strategies for CG disposal. While the low reactivity of CG restricts its large-scale applications. To increase the reactivity of CG, wet-grinding treatment was conducted in this work. X-Ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) were used to characterize the milled CG. The results indicated that wet-grinding could significantly modify the CG structure, contributing to it reactivity increase when using as SCMs. Using the CG after wet-grinding as SCMs significantly accelerated the composites setting and compressive strength development, with the matrix of lower porosity. The compressive strength of CG/OPC composites increased by around 71% using CG12 as SCMs. [Display omitted] •Wet-grinding was used to increase the pozzolanic reactivity of coal gangue.•No aggregation phenomenon was noticed during the wet-grinding.•Using wet-ground coal gangue as SCMs significantly increased the compressive strength of cement composites.•All the cement composites present good immobilization capacity of heavy metals.