Pore-Scale Modeling of Mineral Growth and Nucleation in Reactive Flow

Abstract

A fundamental understanding of mineral precipitation kinetics relies largely on microscopic observations of the dynamics of mineral surfaces exposed to supersaturated solutions. Deconvolution of tightly bound transport, surface reaction, and crystal nucleation phenomena still remains one of the main challenges. Particularly, the influence of these processes on texture and morphology of mineral precipitate remains unclear. This study presents a coupling of pore-scale reactive transport modeling with the Arbitrary Lagrangian-Eulerian approach for tracking evolution of explicit solid interface during mineral precipitation. It incorporates a heterogeneous nucleation mechanism according to Classical Nucleation Theory which can be turned “on” or “off.” This approach allows us to demonstrate the role of nucleation on precipitate texture with a focus at micrometer scale. In this work precipitate formation is modeled on a 10 micrometer radius particle in reactive flow. The evolution of explicit interface accounts for the surface curvature which is crucial at this scale in the regime of emerging instabilities. The results illustrate how the surface reaction and reactive fluid flow affect the shape of precipitate on a solid particle. It is shown that nucleation promotes the formation of irregularly shaped precipitate and diminishes the effect of the flow on the asymmetry of precipitation around the particle. The observed differences in precipitate structure are expected to be an important benchmark for reaction-driven precipitation in natural environments.

In Situ Observations of Barium Sulfate Nucleation in Nanopores

“…The SAXS data indicate that the phase that nucleates within the nanopores rapidly saturates and does not grow to large sizes, whereas barite growth in the intergranular micropores proceeds at rates consistent with other experimental studies. , This interpretation is consistent with recent results of pore-scale reactive transport modeling, which show that reactive species tend to be consumed by growth or nucleation at the entrance to the pore leading to low supersaturation states inside the pore. In addition, the nonbulk barite phase preferentially filled in the nanopores may limit barite growth, as heteroepitaxy between mismatched phase structures can result in self-limiting thin-film growth. , …”

Real-Time Atomic-Scale Structural Analysis Resolves the Amorphous to Crystalline CaCO3 Mechanism Controversy

“…To analyze the dissolution kinetics of the ACC in the experiment, we conducted reactive transport simulations using dissolFoam solver developed for dissolution and precipitation problems, which include a dynamic boundary between fluid and solid. , For detailed modeling parameters, see the Supporting Information.…”

Numerical Study of Mineral Nucleation and Growth on a Substrate

“…24 They found that at a high saturation index (SI), homogeneous nucleation prevented the formation of barite through heterogeneous nucleation (epitaxially grown rim) at pore scale. Work by Starchenko 25 incorporates probabilistic nucleation into the pore-scale model based on the arbitrary Lagrangian-Eulerian approach. The nucleation was implemented on explicit interfaces of solid particles in reactive flow.…”