Development of High-Strength Glass–Ceramic Materials by Utilization of Slag Discharged from Steel-Making Industry in Korea

Every year 25 million tons of slag is generated as an industrial by-product by the steel-making industry in Korea. Using slag to manufacture high-strength glass–ceramic materials is increasingly becoming a feasible option, and recently several types of slag have been used in combination to manufacture glass–ceramic materials such as basalt-based glass–ceramics. Glass–ceramic materials with two different chemical compositions were prepared using Fe–Ni slag, basic oxygen furnace slag, dephosphorization slag, and fly ash by melting and casting and a subsequent heat treatment. X-ray diffraction analyses confirmed that clinopyroxene and CaAl₂SiO₈ were the primary phases in the formed glass–ceramics, while thermogravimetry and differential thermal analyses showed that their glass-transition points were 709–724 °C and crystallization temperatures were 888–918 °C. The morphologies and constituent components were also examined using field emission scanning electron microscopy and energy-dispersive X-ray spectroscopy. The stable phases were calculated as functions of the temperature using FactSage. Finally, the compressive strength, Vickers hardness, and wear rate values of the glass–ceramics were evaluated in order to elucidate their physical properties.