Tesis doctoral de Patricia Acero Salazar
Weathering of sulfidic waste resulting from mining activities is a major environmental problem. When exposed to air, these wastes may produce acid waters (ph typically between 2 and 4) with high concentrations of sulfate, iron and other potentially pollutant elements (acid mine drainage; amd). Sustainable amd remediation requires a previous knowledge and quantitative evaluation of weathering processes and their complex interactions. This thesis deals with some of the key processes and interactions. the main weathering process generating metal-bearing acid drainage is the dissolution of sulfide minerals. In the first part of this thesis, the dissolution kinetics in acid environment of three sulfide minerals (namely sphalerite; zns, chalcopyrite; cufes2, and galena; pbs) were studied by long term flow-through experiments. The influence of ph, dissolved oxygen and temperature on the dissolution rates was assessed. The three sulfides exhibited very different dependence on ph. In contrast to pyrite behavior, dissolution rates of sphalerite and chalcopyrite were found to be independent of dissolved oxygen and galena dissolution was only dependent on dissolved oxygen at ph above 2. Dissolution rate laws for these sulfide minerals were also proposed. These laws can be incorporated into reactive transport models, allowing the performance of more realistic calculations and predictions. the dissolution of pyrite and some other sulfides is oxidative and the availability of oxygen is a key factor in the generation of acid waters. Oxygen availability is enhanced in the vadose zone of mine tailings and related polluted soils. Therefore, the second part of this thesis was aimed at studying geochemical and thermohydraulic processes in the vadose zone. With this aim, unsaturated column experiments were carried out. Columns were forced to dry by heating and the evolution with depth of water content, temperature, porewater hydrochemistry and solid phases was examined at different
Datos académicos de la tesis doctoral «Weathering of sulfides and natural attenuation of acid mine waters«
- Título de la tesis: Weathering of sulfides and natural attenuation of acid mine waters
- Autor: Patricia Acero Salazar
- Universidad: Politécnica de catalunya
- Fecha de lectura de la tesis: 08/06/2007
Dirección y tribunal
- Director de la tesis
- Carlos Ayora Ibáñez
- Tribunal
- Presidente del tribunal: pierfranco Lattanzi
- josep María Soler matamala (vocal)
- Gimeno serrano María José (vocal)
- bernhard Dold (vocal)