Leaching of spent selective catalytic reduction catalyst using alkaline melting for recovery of titanium, tungsten, and vanadium

Abstract

To develop a method for recovering titanium (Ti), tungsten (W), and vanadium (V) from a spent selective catalytic reduction (SCR) catalyst, leaching of the catalyst after alkaline melting was investigated. The spent SCR catalyst reacted with sodium carbonate (Na2CO3) at 1273 K. In water leaching, the influence of temperature, basicity, and solid/liquid (S/L) ratio (w/v) on the dissolution of the soda-melted catalyst was studied. The leaching efficiency of both W and V was larger than 99.2% at 303–373 K under 2–20% S/L ratio. In the subsequent HCl leaching, the influence of HCl molarity and temperature on the leaching was investigated. The critical concentration of HCl solution for obtaining a high leaching efficiency of Ti at 323–353 K under 10% S/L ratio was determined, and the correlation between the molarity and temperature was determined. The HCl leaching efficiency of Ti was 98.3% when an 8 M HCl solution was used at 353 K under a 10% S/L ratio for 3 h. Therefore, this study demonstrated an effective method for recovering Ti, W, and V from the spent SCR catalyst.