title: Galena weathering under simulated calcareous soil conditions.
abstract: Exploitation of polymetallic deposits from calcareous mining sites exposes galena and others sulfides to weathering factors. Galena weathering leads to the formation of lead phases (e.g., PbSO(4), PbCO(3)) with a higher bioaccessibility than galena, thus increasing the mobility and toxicity of lead. Despite the environmental impacts of these lead phases, the mechanisms of galena oxidation and the transformation of lead secondary phases, under neutral-alkaline carbonated conditions, have rarely been studied. In this work, an experimental approach, combining electrochemical and spectroscopic techniques, was developed to examine the interfacial processes involved in the galena weathering under simulated calcareous conditions. The results showed an initial oxidation stage with the formation of an anglesite-like phase leading to the partial mineral passivation. Under neutral-alkaline carbonated conditions, the stability of this phase was limited as it transformed into a cerussite-like one. Based on the surface characterization and the formation of secondary species, the weathering mechanisms of galena in calcareous soil and its environmental implications were suggested.
authors.affiliation: Instituto de Metalurgia, Facultad de Ingeniería, Universidad Autónoma de San Luis Potosí, Av. Sierra Leona # 550, Lomas 2a. Sección, 78210, San Luis Potosí, S.L.P., Mexico.
authors.forename: René H
authors.initials: RH
authors.lastname: Lara
authors.forename: Roberto
authors.initials: R
authors.lastname: Briones
authors.forename: Marcos G
authors.initials: MG
authors.lastname: Monroy
authors.forename: Martine
authors.initials: M
authors.lastname: Mullet
authors.forename: Bernard
authors.initials: B
authors.lastname: Humbert
authors.forename: Manuel
authors.initials: M
authors.lastname: Dossot
authors.forename: Ghinwa M
authors.initials: GM
authors.lastname: Naja
authors.forename: Roel
authors.initials: R
authors.lastname: Cruz
mesh_terms: D004784:Environmental Monitoring; D007854:Lead / Q000032:analysis* / Q000737:chemistry; D008800:Mexico; D010084:Oxidation-Reduction; D012987:Soil / Q000737:chemistry*; D013440:Sulfides / Q000032:analysis* / Q000737:chemistry
chemical_list: D012987:Soil; D013440:Sulfides; C018391:lead sulfide; D007854:Lead