Production of steel in the electric arc furnace generates a dust by-product containing non-ferrous metals. EAF dusts are classified as hazardous wastes and are disposed in specialised landfills after stabilisation with hydraulic binder. The process studied in the Laboratory of Materials Electrochemistry consists in an hydrometallurgical treatment of waste based on selective leaching of zinc and lead. At first, a leaching is carried out with a chelating agent, the hydrogenonitrilotriacetate anion. The treatment of different EAF dust samples allows the total leaching of ZnO and PbOHCl. In all cases, solubilized iron level does not exceed 3% in mass. The recovery of metals is performed by precipitation of metallic sulphides with Na2S4. Metallic sulphides can be use in their own metallurgy as raw materials whereas the reagent can be recycled in the process. The leaching residues are inert according to the leaching procedure Afnor X31- 210, but contain important amounts of zinc under ZnFe2O4 form. The recovery of this element requires the destruction of the ferrite structure. For this, ZnFe2O4 is treated by FeCl3, 6 H2O at 150 °C. The whole zinc is extracted. Ultimate solid residues, iron concentrated and free from zinc can be oriented towards steel industry.