Preparation of Glass‐Ceramics Based on Ti‐Bearing Blast Furnace Slag and Coal Fly Ash

ABSTRACT In this study, glass‐ceramics with ultrahigh mechanical strength were successfully prepared through the powder sintering method, using Ti‐bearing blast furnace slag (TBFS) and coal fly ash (CFA) as raw materials. To improve the sintering ability of high‐basicity metallurgical solid waste TBFS, this paper incorporated 30% CFA and achieved “cold adjusting” through high‐energy ball milling. In addition, the effects of TiO 2 content, sintering temperature, and durations on the densification process, crystallization behavior, microstructure, and mechanical properties of the glass‐ceramics were investigated. The results indicated that with increasing TiO 2 content, the linear shrinkage of the glass‐ceramic increased, and the grain size decreased significantly. Meanwhile, the microstructure became more uniform, and the mechanical properties markedly improved. However, a slight decline was observed when the TiO 2 content was further increased to 15%. When the TiO 2 content was 10% and 15%, a notable induced crystallization behavior was observed for Ti‐free phases, which exhibited a distinct preferred orientation. When TBFS with 10% TiO 2 and 30% CFA were sintered at 900°C for 1 h, the predominant crystalline phases were Ca 2 (Mg 0.5 Al 0.5 )(Si 1.5 Al 0.5 O 7 ) and Ca 1.00 Mg 0.39 Ti 0.35 Ti 0.13 Al 0.13 (Al 0.74 Si 1.26 )O 6 , with average grain sizes of 304 and 241 nm, respectively. The flexural strength reached 249.5 MPa, with acid and alkali resistance values of 98.18% and 99.78%, respectively. This study provided a solution for the ultralow‐cost preparation of ultrahigh‐performance glass‐ceramics directly using solid waste containing a glass phase, enabling high‐value utilization of industrial solid waste while reducing the demand for natural stone in the building materials industry.