Aquatic Geochemistry

, Volume 12, Issue 3, pp 269–298

The Removal of Dissolved Metals by Hydroxysulphate Precipitates during Oxidation and Neutralization of Acid Mine Waters, Iberian Pyrite Belt

  • J. Sánchez España
  • E. López Pamo
  • E. Santofimia Pastor
  • J. Reyes Andrés
  • J. A. Martín Rubí
Article

DOI: 10.1007/s10498-005-6246-7

Cite this article as:
España, J.S., Pamo, E.L., Pastor, E.S. et al. Aquat Geochem (2006) 12: 269. doi:10.1007/s10498-005-6246-7

Abstract

This study examines the removal of dissolved metals during the oxidation and neutralization of five acid mine drainage (AMD) waters from La Zarza, Lomero, Esperanza, Corta Atalaya and Poderosa mines (Iberian Pyrite Belt, Huelva, Spain). These waters were selected to cover the spectrum of pH (2.2–3.5) and chemical composition (e.g., 319–2,103 mg/L Fe; 2.85–33.3 g/L SO4=) of the IPB mine waters. The experiments were conducted in the laboratory to simulate the geochemical evolution previously recognized in the field. This evolution includes two stages: (1) oxidation of dissolved Fe(II) followed by hydrolysis and precipitation of Fe(III), and (2) progressive pH increase during mixing with fresh waters. Fe(III) precipitates at pH < 3.5 (stages 1 and 2) in the form of schwertmannite, whereas Al precipitates during stage 2 at pH 5.0 in the form of several hydroxysulphates of variable composition (hydrobasaluminite, basaluminite, aluminite). During these stages, trace elements are totally or partially sorbed and/or coprecipitated at different rates depending basically on pH, as well as on the activity of the SO4= anion (which determines the speciation of metals). The general trend for the metals which are chiefly present as aqueous free cations (Pb2+, Zn2+, Cu2+, Cd2+, Mn2+, Co2+, Ni2+) is a progressive sorption at increasing pH. On the other hand, As and V (mainly present as anionic species) are completely scavenged during the oxidation stage at pH < 3.5. In waters with high activities (> 10−1) of the SO 4= ion, some elements like Al, Zn, Cd, Pb and U can also form anionic bisulphate complexes and be significantly sorbed at pH < 5. The removal rates at pH 7.0 range from around 100% for As, V, Cu and U, and 60–80% for Pb, to less than 20% for Zn, Co, Ni and Mn. These processes of metal removal represent a significant mechanism of natural attenuation in the IPB.

Keywords

acid mine drainageFe(III) hydrolysisschwertmannitemetal sorptionnatural attenuation

Copyright information

© Springer 2006

Authors and Affiliations

  • J. Sánchez España
    • 1
  • E. López Pamo
    • 1
  • E. Santofimia Pastor
    • 1
  • J. Reyes Andrés
    • 2
  • J. A. Martín Rubí
    • 2
  1. 1.Dirección de Recursos Minerales y GeoambienteInstituto Geológico y Minero de España (IGME)Rios Rosas 23Spain
  2. 2.Centro de Laboratorios y Técnicas de ApoyoInstituto Geológico y Minero de España (IGME)La Calera 1Spain