EAFD-loaded vitreous and glass-ceramic materials

SiO2, Na2O and CaO were mixed and co-melted with electric arc furnace dust waste. The resulting vitreous materials, produced by quenching at ambient atmosphere, were transformed into glass-ceramics by two-stage heat treatment, under thermal conditions that were determined by differential thermal analysis. X-ray diffraction, scanning electron microscopy, energy dispersive spectrometry and transmission electron microscopy were employed to investigate the physical properties of all products. It was found that whilst wollastonite (CaSiO3) separates from the parent matrix as the dominant crystalline phase in all glass-ceramic products, the crystallization mode depends on the batch composition. Leaching tests evidenced that vitreous products were chemically durable. Devitrification did not significantly affect leach resistance so glass-ceramic materials retain the leach resistance that was achieved by vitrification.