Synthesis and Characterization of Nano-Structured Fly Ash: A Waste from Thermal Power Plant

Abstract

In this work an attempt has been made to modify micro-sized fly ash into nano-structured fly ash using high-energy ball milling. The smooth, glassy, and inert surface of the fly ash can be altered to a rough and more reactive surface by this technique. Ball milling was carried out for a total duration of 30 h. A sample was removed after every 5 h of milling for characterization. The nano-structured fly ash was characterized for its crystallite size, lattice strain, and percentage crystallinity by X-ray diffraction. A steady decrease in crystallite size and increased lattice strain were observed with milling time; the crystallite size at 30 h milling time was found to be 23 nm, 21 nm, and 16 nm for quartz, mullite, and haematite, respectively. The percentage crystallinity was reduced from 63 to 38 per cent. The size, shape, and texture of the fresh and nano-structured fly ash were studied using scanning electron microscopy. The fresh fly ash particles were mostly spherical in shape. The particles milled for 30 h were irregular and their surface morphology was rough.