Method for extracting valuable metal from fuel flying ash through wet processing

The invention discloses a method for extracting valuable metal from fuel flying ash through wet processing. The method includes the main steps that the fuel flying ash is fed into water, ammonium hydroxide is added to adjust the pH to 7-9, and then an oxidizing agent is added to oxidize vanadium into pentavalent vanadium; vanadium enters the solid phase, nickel is left in the liquid phase, filtration and separation are conducted, and filter liquor is discharged after nickel extraction, ion exchange and ammonium removal through alkalifying; and hot water is used for dissolving a vanadium-containing filter cake, and vanadium is deposited after filtration to obtain ammonium metavanadate crystals. The method is an environmental-friendly and economical vanadium and nickel extraction process.