Data_Sheet_1_Pore-Scale Modeling of Mineral Growth and Nucleation in Reactive Flow.zip

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.

对矿物沉淀动力学的基本理解在很大程度上依赖于对暴露于过饱和溶液中的矿物表面动态的微观观察。紧密结合的传输、表面反应和晶体成核现象的解卷积仍然是主要挑战之一。特别是，这些过程对矿物沉淀的纹理和形态的影响尚不明确。本研究提出了一种孔隙尺度反应传输模拟与任意拉格朗日-欧拉方法相结合的方法，以追踪矿物沉淀过程中显式固体界面的演化。该方法根据经典成核理论纳入了异质成核机制，该机制可开启或关闭。此方法使我们能够展示成核对沉淀纹理的作用，重点关注微米尺度。在本工作中，沉淀形成是在反应流中10微米半径的颗粒上进行的。显式界面的演化考虑了表面曲率，这在出现不稳定性的区域内对于此尺度至关重要。结果表明，表面反应和反应流体流对固体颗粒上沉淀形状的影响。研究表明，成核促进了不规则形状沉淀的形成，并减弱了流体对颗粒周围沉淀不对称性的影响。预计沉淀结构中的观察到的差异将成为自然环境中反应驱动沉淀的重要基准。