Production of insulating glass ceramics from thin film transistor-liquid crystal display (TFT-LCD) waste glass and calcium fluoride sludge

Abstract

Abstract This study investigated the feasibility of producing insulating glass ceramic from thin film transistor-liquid crystal display (TFT-LCD) waste glass and calcium fluoride sludge by vitrification and ceramization processes. This study also explored the effects of MgO as a modifying agent on the flexural strength and dielectric constants. Five different mixing ratios of waste and MgO were analyzed. The major mixture composition is CaF2–MgO–SiO2–Al2O3. In the experiments, the initial glasses were obtained by vitrifying mixtures and then heating the initial glasses to produce glass ceramics. The mixture in which the proportion of TFT-LCD waste glass to calcium fluoride sludge was 7 to 3, with 5 wt% MgO added, underwent complete densification at a relatively low temperature (780 °C). Compared to other mixtures, its flexural strength (140 MPa) was higher, and its dielectric constant (6.4 at 1 MHz) was lower. With increasing MgO content, the initial glasses exhibited lower crystallization temperatures. The results also indicate that densification is considerably hindered by the onset of crystallization, resulting in a decrease in the apparent density and flexural strength. The results demonstrate that the TFT-LCD waste glass with calcium fluoride sludge as the fluxing agent and MgO as the modifying agent can be used as a raw material for producing insulating glass ceramics.