Abstract Solution flow profiles near a mineral surface can exert significant influences on the local thermodynamic driving force and, potentially, the rate-controlling kinetic mechanism of its dissolution or precipitation. These influences are investigated here both by in situ digital holographic microscopy of calcite in flowing pure water and by lattice Boltzmann reaction-transport simulations using close to the same macroscopic flow rates and sample geometry as the experiments. The measurements show that the median dissolution rate along the crystal surface decreases significantly with distance along the flow direction. At lower flow rates localized advancement of the surface, rather than retreat, is sometimes observed near the trailing edge of a macroscopic crystal, which suggests some precipitation even though pure water is injected near the crystal's leading edge. The simulations confirm that the lower rates are caused by an accumulation of dissolved species as the solution flows from the leading to the trailing edge. The experiments and simulations both indicate that the effect is lessened as the flow rate increases but never becomes negligible within the range of flow rates examined. This study implies that dissolution rates are significantly influenced by near-surface conditions even under relatively high flow rates where a surface process, not diffusion, controls the rate.

中文翻译：

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影响矿物溶解速率的水动力因素

摘要 矿物表面附近的溶液流动剖面可以对局部热力学驱动力产生重大影响，并可能对其溶解或沉淀的速率控制动力学机制产生重大影响。这些影响在这里通过流动纯水中方解石的原位数字全息显微术和使用与实验接近相同的宏观流速和样品几何形状的晶格玻尔兹曼反应传输模拟来研究。测量结果表明，沿晶体表面的中值溶解速率随着沿流动方向的距离而显着降低。在较低的流速下，有时会在宏观晶体的后缘附近观察到表面的局部前进，而不是后退，这表明即使在晶体前缘附近注入纯水，也会有一些沉淀。模拟证实较低的速率是由溶解物质的积累引起的，因为溶液从前缘流向后缘。实验和模拟都表明，随着流速的增加，影响会减弱，但在所检查的流速范围内绝不会变得可以忽略不计。该研究表明，即使在相对较高的流速下，溶解速率也受近表面条件的显着影响，其中表面过程而不是扩散控制速率。实验和模拟都表明，随着流速的增加，影响会减弱，但在所检查的流速范围内绝不会变得可以忽略不计。该研究表明，即使在相对较高的流速下，溶解速率也受近表面条件的显着影响，其中表面过程而不是扩散控制速率。实验和模拟都表明，随着流速的增加，影响会减弱，但在所检查的流速范围内绝不会变得可以忽略不计。该研究表明，即使在相对较高的流速下，溶解速率也受近表面条件的显着影响，其中表面过程而不是扩散控制速率。