Transport Properties Of Interfacial Si-Rich Layers Formed On Silicate Minerals During Weathering : Implications For Geothermal Purposes

Abstract

The dissolution of silicate minerals is of primary importance for various processes ranging from chemical weathering to co2 sequestration. Whether it determines the rates of soil formation, co2 uptake and its impact on climate change, channeling caused by hydrothermal circulation in reservoirs of geothermal power plants, durability of radioactive waste confinement glasses or geological sequestration of co2, the same strategy is commonly applied for determining the long term evolution of fluid-rock interactions. This strategy relies on a bottom-up approach, where the kinetic rate laws governing silicate mineral dissolution are determined from laboratory experiments. However, a long-standing problem regarding this approach stems from the observation that laboratory-derived dissolution rates overestimate their field counterparts by orders of magnitude, casting doubt of the accuracy and relevance of predictions based on reactive-transport simulations.