Preparation of high-purity TiSi2 and eutectic Si-Ti alloy by separation of Si-Ti alloy for clean utilization of Ti-bearing blast furnace slag

Titanium-bearing (Ti-bearing) blast furnace slag is not only industrial waste but also an important Ti resource. However, the cleaning of Ti-bearing blast furnace slag for utilization is a difficult problem. In this study, a new process is proposed to prepare Titanium disilicide (TiSi2) and eutectic Si-Ti alloy (Si/TiSi2), using Ti-bearing blast furnace slag and low-purity Si as raw materials. Firstly, Titanium oxide (TiO2) in the Ti-bearing blast furnace slag was reduced by Si and an Si-Ti alloy was obtained. The obtained Si-Ti alloy was then separated into TiSi2 and eutectic Si-Ti alloy by directional crystallization. In addition, MgO, Al2O3 and graphite crucibles were used and their influences on the results were investigated to obtain the optimal reaction container to prepare high-purity TiSi2 and eutectic Si-Ti alloy. The results show that the separation of Si-Ti alloy using an MgO crucible as a reaction container has little influence on the purity of the TiSi2 (>98%) and eutectic Si-Ti alloy (>97%) and that most of the impurities could be eliminated from the bulk TiSi2 crystal and eutectic Si-Ti alloy. The results of this study provide a theoretical and experimental basis for the simultaneous preparation of TiSi2 and eutectic Si-Ti alloy materials and proposes a new approach for the comprehensive utilization of Ti-bearing blast furnace slag.

Automated summary

A new process was proposed to prepare high-purity Titanium disilicide and eutectic Si-Ti alloy using Ti-bearing blast furnace slag and low-purity Si. The obtained Si-Ti alloy was separated into TiSi2 and eutectic Si-Ti alloy by directional crystallization, with MgO crucibles found to have little influence on the purity of the products. This study provides a basis for the simultaneous preparation of TiSi2 and eutectic Si-Ti alloy materials from Ti-bearing blast furnace slag.