Vitrification of CO2-mineralized steel slag residual: A study on the formulation, high-temperature viscosity-component correlation and chemical durability of glass.

China’s extensive accumulation of steel slag not only occupies significant land resources but also poses risks to soil and groundwater quality. CO2 mineralization technology presents an effective strategy for detoxifying and repurposing steel slag, simultaneously generating valuable carbonates and facilitating carbon sequestration. However, the residual material resulting from CO2 mineralization of steel slag contains hazardous heavy metals and organic compounds, including amino acids that act as leaching agents. This study aimed to stabilize the CO2-mineralized steel slag residue through vitrification, transforming it into a stable glass matrix. Ternary glasses composed of CMSSR–SiO2–Al2O3 were synthesized at a melting temperature of 1300 °C. The glass-forming region was delineated within compositional boundaries of 45–77.5 wt% CMSSR, 22.5–40 wt% SiO2, and 0–15 wt% Al2O3. A representative set of formulations was selected to examine high-temperature viscosity, and a quadratic mixture model was developed to correlate component ratios with the temperature at which viscosity reaches 10 Pa·s. The leaching behavior of heavy metals was evaluated using an acid leaching protocol in accordance with Chinese national standards, with results indicating excellent chemical durability of the vitrified glasses.