Synthesis of waste‐derived glass‐ceramics from MSWI fly ash and EAF dust: Kinetics of nucleation and crystallization

Abstract

The kinetics of crystal nucleation and growth critically affect the conversion of waste into high‐quality glass‐ceramics. This study investigates the effects of prenucleation treatment on the kinetic behavior of a waste‐derived glass‐ceramicsynthesized from a mixture of municipal solid waste incinerator fly ash and electric arc furnace dust. The crystallization kinetic parameters of annealed and prenucleated glass samples were determined by differential thermal analysis under nonisothermal conditions. Prenucleation experimental results revealed a temperature and time of maximum nucleation of 700°C and 30 min, respectively. Crystallographic and microstructural analyses revealed that the main crystalline phases were melilite and augite, with an equiaxed grain morphology, and were embedded in the glassy matrix. The activation energies (Ec) for the crystallization of the annealed and prenucleated glass samples, determined using modified Kissinger and Ozawa equations, were in the ranges of 367.4–395.2 and 199.8–214.6 kJ/mol, respectively. The Avrami constant (n) was 1.8 for the annealed glass and 1.5 for the prenucleated glass. These results confirm a significant difference between the Ec values of the annealed glass and prenucleated glass, suggesting that mixed ash‐based glass is suitable for use in the two‐stage crystallization thermal treatment adopted in this study. © 2012 American Institute of Chemical Engineers Environ Prog, 32: 480–488, 2013