Selective extraction of titanium from Ti-bearing slag via the enhanced depolarization effect of liquid copper cathode

Ti-bearing slag (TiO₂>20 wt%) is a valuable titanium secondary resource. The extraction of titanium from the slag is difficult due to the complex composition and structure. Although molten oxide electrolysis is considered as a promising method, silicon will be preferentially electroreduced compared to titanium due to low theoretical decomposition voltage. In this work, a liquid copper cathode is used to selectively extract titanium from molten Al₂O₃-MgO-CaO-TiO₂-SiO₂ electrolyte. It is found that comparing to silicon, titanium can be preferentially reduced by one-step electron transfer due to the enhanced depolarization effect on a liquid copper cathode. So, Ti-Cu alloys are firstly obtained from molten Ti-bearing slag, and then Ti-Si alloys are co-electrodeposited in the molten oxide electrolyte with low TiO₂ content. It may be ascribed to the larger binding force between titanium and copper than that between silicon and copper. It provides an effective strategy for the separation of titanium from of Ti-bearing slag.