Experimental study on the resource recovery of TiO2 from waste flue gas denitrification catalyst
Alkaline leaching and acid washing at high temperatures were used to treat waste SCR catalysts.The leaching effect of alkaline and acid leaching on the components of catalyst and the influence law of temperature on their leaching behavior were studied.The results indicated that increasing the alkaline leaching temperature was beneficial for the leaching of V and W.The leaching rates of V and W were 82.38％and 74.92％at 210 ℃,respectively.The maximum leaching rate of impurities such as Al,Ca and Na could reach over 98％.High purity of TiO2 could be recycled and used for producing fresh catalyst.The catalyst structure was destroyed by alkaline leaching treatment at high temperatures,which was beneficial for the removal of the impurities in subsequent hydrochloric acid treatment and was better than direct acid washing.Na2TiO3 was generated in the alkaline leaching process at high temperatures,which reacted with hydrochloric acid and then hydrolyzed to form new TiO2 particles,forming more small pores and increasing specific surface area.
waste SCR catalystTiO2alkaline leaching at high temperaturesacid washingresource recovery
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