OXIDISING ELUTRIATION OF CONTAMINATED SLUDGE CONTAINING IRON WITH SEPARATION OF ZINC AND LEAD

摘要

Process for the separation of non-ferrous metals such as Zn and Pb from sludges containing iron, characterized by the following operating steps: a non-selective step of leaching sludges containing iron in an acid oxidizing medium at a pH of less than 2 in a reactor (10) to obtain a leached suspension; a first separation step during which the leached suspension is separated on a filter (6) into a solid fraction (16) and into a solution (20); an oxidation step (9) in which the solution undergoes oxidation by an oxidizing agent (21), causing the conversion of Fe ++ in the solution to Fe +++; reuse of the oxidized solution (4) in the leaching reactor (10), which causes precipitation of Fe +++ in the reactor and its elimination from the solution during the first separation step (16) while the acid bound under form of FeCl3 is recovered.