Novel Environmentally Friendly Leaching Process for Vanadium and Tungsten Recovery from Spent SCR Catalyst

Selective catalytic reduction (SCR) is the best technology to reduce the nitrogen oxides (NOx) emissions in industries. Due to the increasing demand and the limited lifespan of them, after deactivation, they usually end up in landfills posing a major environmental issue. 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 considering the necessity of replacing primary with secondary sources makes the recovery of vanadium and tungsten a major motivation for this research. During this investigation, spent SCR catalyst soda roasting process with dissolved NaOH compared with the traditional NaOH dry roasting and its influence in the subsequent water leaching was studied. With the ideal parameters obtained after optimization, there is a reduction of roasting temperature, leaching time, and the amount of silicon impurities leached alongside the title metals.