Recovery of V2O5 from spent SCR catalyst by H2SO4-ascorbic acid leaching and chemical precipitation

Abstract

Large amounts of spent selective catalytic reduction (SCR) catalysts were produced in industry after losing their activity. This study developed a clean and effective route of leaching and recovery of vanadium (V) from spent SCR catalyst. First, ascorbic acid (C6H8O6) as the adjuvant can enhance vanadium leaching in H2SO4 solution. The effect parameters of acid concentration, leaching temperature, leaching time and liquid-solid (L/S) ratio on the leaching efficiency of vanadium were investigated. Then, the enrichment of vanadium in the leachate to obtain the black cake was carried out through adjusting pH value. The effects of vanadium concentration and pH on the precipitation efficiency of vanadium were studied. Finally, after alkaline dissolution and oxidation of the black cake, ammonium chloride (NH4Cl) was selected and used as the precipitant to obtain the ammonium poly-vanadate (APV). The final product vanadium pentoxide (V2O5) was obtained through roasting APV at 550 ℃ for 1.0 h. The black cake, APV and V2O5 were analyzed by the characterization of XRD or XRF. This study may introduce a new perspective for the effective usage of vanadium from spent SCR catalyst.