Patent attributes
A method for recovering rare earth compounds, vanadium and nickel from waste vanadium-nickel catalysts, comprising steps of: acid leaching, by soaking waste vanadium-nickel catalysts into a sulfuric acid solution and obtaining a mixture containing alumina silica slag; sedimentation, by filtering out the alumina silica slag from the mixture to obtain a filtrate, and then adding a salt into the filtrate to precipitate rare earth double salts followed by isolating a sediment of rare earth double salts and a liquid solution via filtration; and extraction, by providing and adding an alkali into the sediment of rare earth double salts followed by further soaking the rare earth double salts in an acid solution to precipitate rare earth oxalate or rare earth carbonate, and adding an oxidizer into the liquid solution to adjust the pH value thereof and then extracting vanadium and nickel from the liquid solution via an ion-exchange resin.
