Alkali-activation potential of stone wastes

Abstract

The industrial processing of dimensional stones generates a significant amount of waste. According to the data released in 2020 by the nations with active dimensional stone industries, it is estimated that out of 316 million tons of dimensional stones extracted each year, 161.5 million tons end up as mining or quarry waste. These are dumped in open locations creating noxious conditions for mine workers, residents of nearby communities, and the environment. In the current work, an effort has been made to manufacture alkali-activated materials (AAM) using sandstone waste (SW) and marble stone waste (MW) obtained from Rajasthan (India). The primary precursor is SW, whereas MW is partially substituted as an admixture. The elemental composition of stone wastes was determined using X-ray fluorescence spectroscopy (XRF). Stone waste-based geopolymer composite was prepared using alkaline activating solutions sodium hydroxide (NH, NaOH) and sodium silicate (NS, Na2SiO3) and tested for mechanical and physical properties. Characterization and microstructural analysis of geopolymer composite was performed using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM) fitted with energy dispersive X-ray spectroscopy (EDS). The findings suggest that the developed geopolymer composite can be employed as a construction material that will improve the re-utilization of stone wastes, offering a workable solution to the challenges associated with their disposal.