InterPore2026

Investigation of Pore-Scale Dynamics of Dissolution-Precipitation of Mineral Using Micromodels

19 May 2026, 15:05

1h 30m

Poster Presentation (MS20) Special Session in Honor of Jun Yao Poster

Speaker

Ziyou Zhu (南京大学)

Description

Understanding the reaction-transport mechanisms of fracture-matrix systems is critical for ensuring safe and permanent geological CO₂ sequestration. While prior studies mainly focused on the dissolution and precipitation patterns in advection-dominated flow paths, it remains unclear how reaction kinetics govern the spatial topology and co-evolution of the dissolution front, silicon-rich leached layer, and the precipitation front within diffusion-dominated dead-end pores.
To address this, we simulated diffusion-limited mass transfer within dead-end pores by developing a high-temperature and high-pressure microfluidic platform featuring a ‘main channel with lateral cavities’ design. Natural minerals (calcite, chlorite, and plagioclase) are immobilised within the cavities to investigate the impact of mineral heterogeneity and interfacial reaction differences on the coupling mechanisms between silicate dissolution and carbonate precipitation in diffusive regimes. The local Damköhler number (Da) is tuned by varying temperature and mineralogy, while maintaining constant geometry and flow conditions.
The dynamic evolution of mineral dissolution, growth of the silicon-rich leached layer, and secondary carbonate precipitation is quantified using in-situ optical microscopy and SEM-EDS to characterize the morphological evolution of reaction interfaces and identify the chemical composition of the secondary phases.
The results reveal two distinct evolutionary modes at different Da values. At low Da, the dissolution and precipitation fronts are strongly decoupled. A thick, silicon-rich leached layer forms on the mineral surface, acting as a diffusive barrier that retards cation release. Consequently, carbonate nucleation and growth away from the reactive surface as a pore-filling precipitation pattern that preserves the mineral reactivity. Conversely, at high Da, the dissolution and precipitation fronts transition to a coupled mode. Dissolved cations become supersaturated instantaneously at the mineral-solution interface, resulting in the precipitation front converging onto the dissolution front surface. This inhibits leached layer growth and forms a dense carbonate shell (‘armoring effect’), leading to premature passivation and blocking the reaction.
This study link Da to the topological transition of the ‘mineral-leached layer-precipitation’ structure. It elucidates the critical role of the leached layer in regulating reactive transport and precipitation distribution. Our findings suggest that manipulating reaction kinetics to induce precipitation migration into deeper pore spaces can mitigate the ‘armoring effect’, thereby enhancing the effective reaction volume and long-term stability of mineral carbonation for CO₂ storage.