Abstract: The invention relates to a hydrometallurgical process for decontaminating soils 1 which are polluted with metallic elements, comprising a stage of basic leaching I so as to bring about the dissolution of the metallic elements to be removed, a cementation stage II bringing about the precipitation 6 of said elements in metal form, performed by electrochemical exchange with a zinc powder 5 produced by a stage of electrolysis III of the solution 7 originating from the cementation stage. In accordance with the invention a complementary addition of zinc is performed, preferably at the exit of the leaching stage in the form of a leachate 17 of waste from iron and steel manufacture, especially of dust 13 from electrical steel manufacture 15.