Glass-ceramics produced from thin-film transistor liquid-crystal display waste glass and blast oxygen furnace slag

This study employed waste glass from thin-film transistor liquid-crystal displays (TFT-LCD) and slag from a basic oxygen furnace (BOF) to produce CaO–MgO–Al2O3–SiO2 (CMAS) glass-ceramics through vitrification and further heat treatment of compacts of the obtained glass powders for densification and crystallization. CMAS glass-ceramics are known for their excellent mechanical and dielectric properties. MgO and Al2O3 were selected as modifying agents to ensure that the composition of the wastes featured these important characteristics. Our results indicate that a TFT-LCD waste glass to BOF slag ratio of 7:3 yields a glass-ceramic with a primary crystalline phase of anorthite (Al2CaSi2O8). The sample with 20 wt% MgO addition produced a glass-ceramic containing diopside (MgCaSi2O6), due to the presence of excess MgO. The densification of the sample with 20 wt% MgO saturated at 820 °C, resulting in a flexural strength of 140 MPa and dielectric constant in the range of 10–12 at 1 MHz, which satisfy the criteria for glass-ceramic insulation.