Microstructural and Mineralogical Properties of Acid and Alkali Activated Coal Fly Ash

Abstract

Fly ash (FA), a coal combustion residue of thermal power plants has been regarded as a problematic solid waste all over the world. In this study FA samples were modified with NaOH and H2SO4. The mineralogical and microstructural characterization were carried out by means of X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM/EDS) and Braunauer-Emmett-Teller's multilayer adsorption theory (BET). Experimental data showed that cenospheres were dominated with quartz and mullite glasses with both amorphous and crystalline phases. The acid treatment increased Si/Al ratios by removing impurities and dealuminations but alkali treatment significantly increased total pore volume. The specific surface area of alkali and acid treated samples were found 6.9 m 2 g -1 and 2.1 m 2 g -1 respectively, while that of virgin material was 1.5 m 2 g -1 .

Wood biomass fly ash ameliorates acidic, low-nutrient hydromorphic soil & reduces metal accumulation in maize

“…Particles of submicrometre size were found adhering to larger regular spheres, and there were also some clumps or agglomerates of small particles. The morphology of broken microspheres resembled cenospheres (i.e., hollow lightweight microspheres with holes likely filled with gas) as well as planispheres and plerospheres (i.e., hollow, lighter microspheres filled with minute minerals, spongy, foam or additional porous matrix) as observed previously (Mondal et al, 2019;Carević et al, 2019).…”

Development and Characterization of a Novel Soil Amendment Based on Biomass Fly Ash Encapsulated in Calcium Alginate Microspheres

“…A relatively low peak intensity indicates that the hydroxyl groups are unlikely to bond to each other via hydrogen bonds [ 20 ]. Peaks of lower intensity are attributed to quartz (in the ranges 1603–1846 cm −1 and 760–801 cm −1 as well as 460 and 513 cm −1 ) [ 21 ], arcanite (990, 619, and 570 cm −1 ) [ 22 ], periclases (at 3770 and 459 cm −1 ) [ 23 ], and various aluminosilicates (915 to 554 cm −1 ) [ 24 ]. A series of bands characterized by very low intensities can be seen in the middle.…”