Study of Thermal Property of Glass-Ceramics Produced from Soda Lime Glass Waste by Single-Step Sintering Process

Soda lime glass (SLG) is one type of glass mainly used in beverage and food packaging industries. SLG has high potential as starting materials for glass-ceramics (GC) production as SLG consists of large proportion of silicate and has considerably low of melting temperature. In addition, large consumption of beverages and foods, SLG makes up a large bulk of the waste. Producing glass-ceramics (GC) from SLG is thus interesting. Processing of SLG to GC is strongly dependent on their thermal property. Before processing, thermal profile of SLG was analyzed by differential scanning calorimetry; crystallization temperature at 711 °C was identified at the heating rate of 5 °C/min. It was also possible to extract information about crystallization kinetic by applying the Kissinger and the Ozawa relations. It was found that crystallization activation energies were 365.06 and 381.60 kJ/mol, respectively. For the GC processing, SLG powder was mixed with precursors to the ratio of 60SLG-35SiO2-2TiO2-2ZnO-1CuO before sintering with single step method at 711, 800, 850, 900, 950, 1,000 °C. An analysis by XRD has shown that there were two phases; beta-quartz and beta-cristobalite, in the sintered samples. Different sintering temperatures have yielded different proportion of alpha-to beta-phases. SEM/EDX has also revealed uneven distribution of different oxides in the produced glass-ceramics.