Gas-Phase Treatment of Metallurgical Fly Ash in Nitrating Media to Increase the Recovery of Valuable Components Using the Example of Fly Ash Produced by MMC Norilsk Nickel

Abstract A new approach is proposed to increase the recovery of Ni and Cu from the fly ash formed by roasting the copper–nickel matte in the production of nickel at PAO MMC Norilsk Nickel. This approach is based on the gas-phase treatment of fly ash in the HNO 3 (vapor)–air or NO x –H 2 O(vapor)–air atmosphere with subsequent leaching of Ni and Cu with water. It is shown that nitrating media efficiently leach Ni and Cu from the bulk of the fly ash. It is determined that the pretreatment of the fly ash in a nitrating atmosphere at 70–150°C for 5 h makes it possible to reach the practically complete recovery of Ni and Cu with water (~100% of their total content in the fly ash). The recovery of Fe with water in this case does not exceed ~7% of its total content in the fly ash.