The effect of fluxing agent cations in fly ash-based glass on chemical stability

Recycling plays a key role in making the economy more efficient in terms of raw material usage. Coal fly ash (CFA), a by-product of coal combustion in thermal power plants, shares a chemical composition similar to some silicate glasses, making it a viable raw material for glass production. The paper presents the results of Na+ and Ca2+ ion incorporation into coal fly ash-based glass and its impact on chemical stability. The chemical resistance of the glasses was tested in distilled water, 0.01 mol/dm3 HCl, and 0.01 mol/dm3 NaOH. The concentrations of the elements in the solution indicate that the ion exchange process is the dominant dissolution mechanism for both glasses. Na-fly ash glass shows slightly lower stability in all solvents than Ca-fly ash glass. FTIR spectra show no change in the structure of the glasses after contact with solvents. The chemical stability of both glasses is satisfactory with a mass change of less than 1 %.