Ferro, M. C. a, M. H. V. a Fernandas, C. F. M. L. b Figueiredo, M. S. J. G. b Alendouro, and R. C. C. b Monteiro. "
Effect of TiO2 on the crystallization of fly-ash based glass-ceramics."
Materials Science Forum. 455-456 (2004): 831-834.
AbstractA batch of coal fly-ash, soda and lime was melted, quenched to a glass and then devitrified, by one-step heating cycles, forming coarse fibrous microstructures with pores and cracks, resulting in low strength materials. The crystallization behaviour of the based glass was further studied by adding a nucleating agent, TiC2. The resulting structural and microstrutural changes were investigated by differential thermal analysis, scanning electron microscopy, x-ray diffraction, dilatometry and density measurements. The results indicated that the addition of TiO2 could provide a finer grained microstructure, suitable for the production of structural materials.
Alendouro, M. S. J. G. a, R. C. C. a Monteiro, C. F. M. L. a Figueiredo, R. M. S. a Martins, R. J. C. a Silva, M. C. b Ferro, and M. H. V. b Fernandas. "
Microstructural characterization and properties of a glass and a glassceramic made from municipal incinerator bottom ash."
Materials Science Forum. 455-456 (2004): 827-830.
AbstractA glass was made using bottom ash produced by a Portuguese municipal solid waste (MSW) incinerator. The bottom ash was the single batch material used in the formation of the glass, which was obtained through a conventional melt-quenching method. The glass was then converted to glass-ceramic for further recycling to construction materials. After submitting the glass samples to several heat treatments, between 820 and 1050°C and during different times, it was verified that the optimum heat treatment schedule for the ceramization of the glass was at 1000°C for 10h, as confirmed by microstructural observation and by X-ray diffraction. The major crystalline phases precipitated in the glass-ceramic were wollastonite (CaSiO3) and diopside (Ca(Mg,Al)(Si,Al)2O6). Microstructural analysis of the glass-ceramic revealed that the crystalline phases were present as dendrites and fiber-like structures that were homogeneously distributed in the material. The glassceramic showed good mechanical properties with a hardness of 5.6 MPa and a bending strength of 101 MPa. This material had a density of 2.8 gcm-3 and a thermal expansion coefficient of 9.10-6°C-1. The glass and the glass-ceramic showed an excellent chemical stability against leaching in acidic solution and in alkaline solution. In summary, both the glass and the glass-ceramic have good chemical and mechanical properties and can, therefore, be applied as construction materials.