<p>Smelting reduction offers a sustainable pathway for the zero-waste utilization of Ti-bearing blast furnace slag (TBBFS). Nevertheless, the downstream high-value application of the resulting Ti-Si-Fe alloy remains constrained by multiple challenges. In this study, TiB₂ powders were synthesized via a silicothermic reduction process, using the Ti-Si-Fe alloy as both the titanium source and in situ reductant. TiB₂ powders with minor TiC and SiFe phases were obtained at 1050&#xa0;°C in an argon atmosphere. The products exhibited porous morphologies, attributed to silicon dissolution and interfacial reaction between the molten phase and alloy. The addition of sodium oxysalts effectively adjusted the Na₂O/SiO₂ ratio, enabling the removal of sodium silicate via hot water washing. The byproducts are also potentially reusable in water glass production, improving the environmental compatibility of the process. The onset temperatures for reactions between Na₂B₄O₇ and different alloy phases were phase-dependent: 800&#xa0;°C for Ti₅Si₃, 900&#xa0;°C for TiSi and TiSi₂, and 1000&#xa0;°C for TiFeSi₂. The overall reaction followed an interfacial reduction mechanism. This work provides a new route for TiB₂ synthesis from low-cost raw materials, although further optimization is needed for phase purity, product separation, and process scalability.</p> Graphical Abstract <p></p>