title: Leaching and selective copper recovery from acidic leachates of Três Marias zinc plant (MG, Brazil) metallurgical purification residues.
abstract: Zinc plant purification residue (ZPR), a typical Zn-hydrometallurgical waste, was collected from the Três Marias Zn plant (MG, Brazil). ZPR was characterized for its metal content and fractionation, mineralogy, toxicity and leachability. Toxicity characteristics leaching procedure (TCLP) and European Community Bureau of Reference (BCR) sequential extraction results revealed that this ZPR displays high percentages of metals (Cd, Cu, Zn and Pb) in the highly mobilizable fractions, increasing its hazardous potential. Bulk chemical analysis, pH dependent leaching and acid (H2SO4) leaching studies confirm that the ZPR is polymetallic, rich in Cd, Cu and Zn. The sulfuric acid concentration (1 M), agitation speed (450 rpm), temperature (40 °C) and pulp density (20 g L(-1)) were optimized to leach the maximum amount of heavy metals (Cd, Cu and Zn). Under optimum conditions, more than 50%, 70% and 60% of the total Cd, Cu and Zn present in the ZPR can be leached, respectively. The metals in the acid leachates were investigated for metal sulfide precipitation with an emphasis on selective Cu recovery. Metal sulfide precipitation process parameters such as initial pH and Cu to sulfide ratio were optimized as pH 1.5 and 1:0.5 (Cu:sulfide) mass ratio, respectively. Under optimum conditions, more than 95% of Cu can be selectively recovered from the polymetallic ZPR leachates. The Cu precipitates characterization studies reveal that they are approximately 0.1 μm in diameter and mainly consist of Cu and S. XRD analysis showed covellite (CuS), chalcanthite (CuSO4·5H2O) and natrochalcite (NaCu2(SO4)2(OH)·H2O) as the mineral phases. ZPRs can thus be considered as an alternative resource for copper production.
authors.affiliation: Université Paris-Est, Laboratoire Géomatériaux et Environnement (LGE), EA 4508, UPEM, 77454, Marne-la-Vallée, France; UNESCO-IHE Institute for Water Education, Westvest 7, 2611 AX, Delft, The Netherlands; Universidade Federal de Minas Gerais, NGqA-CPMTC, Instituto de Geociências, Av. Antônio Carlos, 6627, Pampulha, Belo Horizonte, MG, 31270-901, Brazil.
authors.forename: Manivannan
authors.initials: M
authors.lastname: Sethurajan
authors.affiliation: Université Paris-Est, Laboratoire Géomatériaux et Environnement (LGE), EA 4508, UPEM, 77454, Marne-la-Vallée, France.
authors.forename: David
authors.initials: D
authors.lastname: Huguenot
authors.affiliation: UNESCO-IHE Institute for Water Education, Westvest 7, 2611 AX, Delft, The Netherlands.
authors.forename: Piet N L
authors.initials: PN
authors.lastname: Lens
authors.affiliation: Universidade Federal de Minas Gerais, NGqA-CPMTC, Instituto de Geociências, Av. Antônio Carlos, 6627, Pampulha, Belo Horizonte, MG, 31270-901, Brazil.
authors.forename: Heinrich A
authors.initials: HA
authors.lastname: Horn
authors.affiliation: Universidade Estadual de Montes Claros, Solos e nutrição de plantas, Avenida Reinaldo Viana, 2630, Bico da Pedra, Janauba, MG, 39440-000, Brazil.
authors.forename: Luiz H A
authors.initials: LH
authors.lastname: Figueiredo
authors.affiliation: Université Paris-Est, Laboratoire Géomatériaux et Environnement (LGE), EA 4508, UPEM, 77454, Marne-la-Vallée, France. Electronic address: Eric.vanHullebusch@univ-paris-est.fr.
authors.forename: Eric D
authors.initials: ED
authors.lastname: van Hullebusch
mesh_terms: D001938:Brazil; D005591:Chemical Fractionation; D003300:Copper / Q000032:analysis* / Q000737:chemistry; D004787:Environmental Pollution / Q000032:analysis*; D006863:Hydrogen-Ion Concentration; D007220:Industrial Waste / Q000032:analysis*; D007700:Kinetics; D008669:Metallurgy; D019216:Metals, Heavy / Q000032:analysis* / Q000737:chemistry; D015032:Zinc / Q000032:analysis* / Q000737:chemistry
chemical_list: D007220:Industrial Waste; D019216:Metals, Heavy; D003300:Copper; D015032:Zinc
keywords: Fractionation; Selective recovery; Sulfide precipitation; Zn metallurgical residue; pH dependent leaching