Green Recovery of Ti, W, and V From Spent V2O5-WO3/TiO2 Catalyst to Prepare W- and V-Containing Si-Ti Alloy

Spent V2O5-WO3/TiO2 catalyst (SVWTC) is considered hazardous waste and a valuable resource of Ti, W, and V. Herein, Ti, W, and V were recovered from waste via silicothermic reduction to prepare W- and V-containing Si-Ti alloys with potential applications. An optimal reduction slag system (CaO-SiO2-TiO2-20 wt pct MgO) and reduction temperature (1773K) were determined to ensure completion of the Si reduction of spent V2O5-WO3/TiO2. The effects of the reduction time (holding time) and basicity (CaO/SiO2 mass ratio) of the initial slag on the separation of the alloy and reduction of Ti, W, and V oxides were investigated. Extending the holding time and basicity of the initial slag improved the separation of the alloy from the residual slag and increased the extraction ratios of Ti, W, and V. The equilibrium time was determined as 6 hours, and the maximum extraction ratios of Ti, W, and V were 96.9, 95.5, and 93.6 pct, respectively. The corrosion of the refractory material during Si reduction was investigated and was controlled at 2.65 pct with high recovery of the oxides. No waste liquid was discharged, and the residual slag could be recycled. This study introduces a green and efficient method for recycling Ti, W, and V from SVWTC and provides a new method for preparing W- and V-containing Si-Ti alloys.

Automated summary

Ti, W, and V were recovered from waste V2O5-WO3/TiO2 catalyst via silicothermic reduction to prepare W- and V-containing Si-Ti alloys. An optimal reduction slag system and temperature were determined, and the effects of holding time and basicity of the initial slag on the separation of the alloy and reduction of Ti, W, and V oxides were investigated. The study provides a green and efficient method for recycling Ti, W, and V from waste catalysts and for preparing W- and V-containing Si-Ti alloys.