Extraction of Vanadium and Tungsten from Waste SCR Denitrification Catalyst by Alkaline Roasting and Water Leaching Process
The alkaline roasting and water leaching process was used to extract vanadium and tungsten from the waste SCR denitrification catalyst for the subsequent resource utilization of vanadium and tungsten.The effects of roasting temperature,roasting time,mass ratio of Na2CO3 to waste catalyst,water leaching temperature,and water leaching time on the leaching effect of vanadium and tungsten were investigated.The roasting mechanism was explored by XRD analysis of roasting products.The experimental results show that the suitable alkaline roasting and water leaching conditions for the waste SCR denitrification catalyst include roasting temperature 875℃,roasting time 1.5 hours,mass ratio of Na2CO3 to waste catalyst 1∶1,water leaching temperature 80℃,and water leaching time 2 h.Under these conditions,the leaching rate of vanadium and tungsten is 91.33%and 96.34%respectively.According to the results of XRD analysis,vanadium and tungsten are converted into easily soluble NaV6O15 and Na2WO4 respectively during the alkaline roasting process.After alkaline roasting and water leaching treatment,more than 90%of vanadium and tungsten enters the water leaching solution,while less than 2%of titanium enters the water leaching solution.
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