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

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 CaF 2 –MgO–SiO 2 –Al 2 O 3 . 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.