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Incorporation of calcium in glasses: A key to understand the vitrification of sewage sludge
Author(s) -
Tarrago Mariona,
Royo Irene,
Martínez Salvador,
GarciaValles Maite,
Neuville Daniel R.
Publication year - 2021
Publication title -
international journal of applied glass science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.383
H-Index - 34
eISSN - 2041-1294
pISSN - 2041-1286
DOI - 10.1111/ijag.15920
Subject(s) - vitrification , materials science , sewage sludge , ceramic , glass recycling , indentation hardness , leaching (pedology) , mineralogy , glass ceramic , metallurgy , raw material , glass production , pyroxene , wollastonite , liquidus , basalt , sewage , waste management , environmental science , microstructure , geology , chemistry , geochemistry , soil water , olivine , soil science , andrology , engineering , medicine , organic chemistry , alloy
The quantity of sewage sludge generated daily by wastewater treatment plants represents a major environmental problem and a financial burden for plant operators. Valorization strategies focusing on reusing sewage sludge as a raw material are currently developed. Vitrification can help us reduce the volume of waste and binds the components in the structure of chemically stable glasses and glass‐ceramics. In this study, the vitrification of sewage sludge inside a basaltic rock has been simulated by producing glasses and a glass‐ceramic from basalt enriched in calcium that lie between the stability fields of pyroxene and melilite in the system CaO–MgO–SiO 2 –Al 2 O 3 . CaO addition causes the oxidation of the melt at above the liquidus, increases the crystallization temperature, decreases the melting temperature, and improves the microhardness of the glasses. Glass‐ceramic processes improves the properties of the Ca‐doped basalt glass. The microhardness of the glass (8.2 GPa) and the glass‐ceramic (8.6 GPa) and leaching tests (in the ppb range) place both the glass and the glass‐ceramics at the high end of the mechanical properties and chemical resistance of ceramic tiles for the building industry.