Crystalline phase control of glass ceramics obtained from sewage sludge fly ash

• Published in: Ceramics international Vol. 29; no. 2; pp. 223 - 227
• Main Authors: Park, Young Jun, Moon, Soon Ok, Heo, Jong
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 2003; Elsevier Science
• Subjects: Applied sciences; Building materials. Ceramics. Glasses; Chemical industry and chemicals; Cross-disciplinary physics: materials science; rheology; Crystal phases; D. Glass ceramics; Exact sciences and technology; Glass-based composites, vitroceramics; Glass-ceramics; Glasses; Materials science; Other industrial wastes. Sewage sludge; Other materials; Physics; Pollution; Sewage sludge fly ash; Specific materials; Wastes; D. Glass ceramics; Crystal phases; Sewage sludge fly ash; Combustion residue; Vickers hardness; Heat treatment; Waste treatment; Raw materials; Phase analysis; Fabrication property relation; Sewage sludge; Density; Fly ash; Upgrading; Thermal expansion coefficient; Chemical properties; Scanning electron microscopy; Crystalline phase; Crystallization; Mechanical properties; X ray diffraction; Microhardness; Physical properties; Tailings; Thermal properties; Bending strength; Incineration; Preparation; Waste reuse; Solid waste; Glass ceramics
• ISSN: 0272-8842; 1873-3956
• DOI: 10.1016/S0272-8842(02)00109-8

Different types of glasses and glass-ceramics were made using fly ash from sewage sludge incinerators. The optimum nucleation condition was heating at 760 °C for 1 h. Crystallization of the nucleated specimen in the region of 1050–1200 °C resulted in the formation of two crystalline phases, i.e. anorthite and diopside. The relative fractions of these two phases changed with crystallization temperature. Specimens heat-treated for 2 h at 1050 °C consisted mainly of diopside crystals with a minor proportion of anorthite. On the other hand, those heat-treated at 1150 °C were primarily composed of anorthite. Glass-ceramics containing large amounts of diopside (1050 °C/2 h) generally displayed better physical and chemical properties than their anorthite counterparts (1150 °C/3 h) due to the interlocking microstructure of diopside crystals.