Coupled fluid flow and chemical reactions in unsaturated pyrite tailings

摘要

Pyrite tailings columns were desiccated by heating and dismounted at sequential evaporation stages. Their pore waters and solid phases were interpreted by thermo-hydro-geochemical reactive transport modeling. Oxygen diffusion in the unsaturated zone leads to pyrite weathering and subsequent silicate dissolution.Evaporation at the top of the columns drove capillary upflow and mass transport to the surface, producing sulfate crusts. These crusts reduced column evaporation and promoted downwards water vapor flux. Water vapor condensed at depth resulting in dilution of pore waters.