To save resources with a device for capturing the flying ashes in the waste gases produced from an incineration furnace, etc., and separates and recovers lead compds. by adding an acid thereto by recovering the acid in the waste gases after the removal of the flying ashes and using this acid for the sepn. and recovery of the lead compds., thereby reutilizing the recovered lead and zinc.

After the waste gases produced from the melting furnace A are cooled by a cooling means 1, the capturing of the molten flying ashes and dust is executed by a dust collector 2. The device is provided with a flying ash treating system C consisting of a recovering system C1 for separating and recovering the lead compds. and a zinc recovering system C2 for separating and recovering the zinc compds. in order to recover the lead and zinc included in the molten flying ashes. The molten flying ashes are first put into a mixing tank 12 and are mixed with water 13 to form a slurry in order to allow the smooth extraction by the acid in the post stage. This slurry is introduced into an acid extracting tank 14 where the acid is added to the slurry and the precipitate (lead precipitate) is separated. The acid recovered by cleaning in a water cleaning column 3 is used as the acid to be added at that time.