Resourceful Utilization of Ironmaking Waste: Synthesis of Ti₅Si₃ Alloy from Titanium-Bearing Blast Furnace Slag

Abstract

Titanium-bearing blast furnace slag (TBFS), a byproduct of ironmaking processes, has long been discarded as waste, resulting in the squandering of valuable resources such as titanium. The recovery and effective utilization of TBFS hold immense significance and importance. This study reports a direct electrolysis method for synthesizing Ti5Si3 alloy from a TBFS/SiO2 mixture in molten CaCl2 at 950°C. A comprehensive investigation was conducted into the phase and morphological evolution during the electrolysis process, along with an analysis of the migration behavior of impurities such as Ca and Al present in TBFS. The synthesized Ti5Si3 alloy powder was systematically characterized and analyzed using scanning electron microscopy, transmission electron microscopy, and other techniques. The results reveal that the electrolysis process encompasses electrochemical deoxidation, in-situ alloying, and self-purification. Furthermore, this study achieved further purification of the Ti5Si3 alloy through vacuum laser rapid melting, effectively volatilizing and removing the residual impurity elements, resulting in an increase in the purity of Ti5Si3 alloy from 96.8% to 98.6%. The resultant Ti5Si3 alloy exhibits excellent corrosion resistance in phosphate buffer solution. In summary, this work provides a crucial technical paradigm and scientific theoretical foundation for the resourceful and value-added utilization of ironmaking solid waste, specifically TBFS.