Solvent Extraction Separation of Tungsten and Vanadium from Simulated Leaching Solution of Spent SCR Catalyst

It is of great significance for the resource utilization of spent SCR catalysts to separate tungsten and vanadium from leaching solutions. In this study, selective separation of vanadium from a mixed solution of tungsten and vanadium was investigated by solvent extraction using ammonium salts as extractant. The effect of different parameters including initial pH, phase ratio, temperature, and time was studied, respectively. The results demonstrated tungsten and vanadium mainly exist in the form of WO42- and V4O124- in solutions with pH ranging from 8.5 to 9.5 by simulation calculation. In addition, it was found that vanadium can be easily extracted over tungsten by methyl trioctyl ammonium chloride (Aliquat 336). More than 93.5% of vanadium was extracted, while most of the tungsten remained in raffinates under the optimal conditions (initial pH 8.4, 10 vol.% N263, contact time 30 min, temperature 25 degrees C and phase ratio (O/A) 1/6).