Effects of nucleating agents on crystallization of arc-molten slag from incinerator fly ash

Glass-ceramics obtained from the electric arc furnace molten slag of incinerator fly ash was produced by applying nucleation and crystallization through heat treatment process. The effects of nucleating agent (TiO₂ and Cr₂O₃)on the crystallization kinetics and heat treatment schedule of the slag were investigated. The results show that the nucleating agents changed the crystallization phase and morphology of the obtained glass-ceramics. The optimum heat treatment schedule of the glass with TiO₂ was determined as nucleation at 952 K for 1.5 h and crystal growth at 1258 K for 1.5 h, while those values with Cr₂O₃ were estimated at 971 K for 2 h and at 1 238 K for 2 h. TiO₂ acting as nucleating agent could decrease the activation energy of the slag and shorten the total thermal treatment time in comparison with Cr₂O₃. The glass-ceramics obtained under the optimum heat treatment condition was environment-friendly and had remarkable physical/mechanical properties and chemical durability.