Recovery and Separation of Vanadium and Tungsten from Spent SCR Catalyst by Hydrometallurgical/Hybrid Routes

One of the most harmful air contaminants is nitrogen oxides (NOX) produced usually in combustion processes. To reduce the effluents, the most effective technology to date is selective catalytic reduction (SCR) where nitrogen oxides are reduced into nitrogen to be released freely. Due to the increasingly strict environmental regulations, the demand for SCR catalystsSCR catalyst has increased, and inevitably, the necessity of disposal of those spent catalysts has increased accordingly. Most catalysts for stationary applications contain around 0.5–1.5% wt V2O5 and 7–10% wt of WO3 in a TiO2 glass fiber matrix, and due to the environmental burden of disposal and the necessity of finding secondary sources for vanadiumVanadium (V) and tungstenTungsten (W), the recyclingRecycling of spent SCR catalystSCR catalyst becomes a pressing issue for current research. During this investigation, different tertiary amines were used and compared to observe the effectiveness in the extractionExtraction of vanadiumVanadium and tungstenTungsten from spent SCR catalystSCR catalyst, the enrichmentEnrichment process was optimized and the loaded organic (9 times concentration) went through a crowdingCrowding process where vanadiumVanadium was replaced by tungstenTungsten to obtain highly pure tungstenTungsten loaded organic. The crowdingCrowding parameters such as crowdingCrowding agent, concentration, and pH were optimized.