Abstract Using kinetic Monte Carlo simulations and scaling approaches, we describe the far from equilibrium calcite dissolution in neutral to alkaline solution and in scales ranging from the molecule detachment from surfaces to that of crystalline grains. The parameters of the thermally activated model are calibrated by the velocities of terrace steps and densities of monolayer pits measured in atomic force microscopy works. The application to nanosized crystalline grains shows that they dissolve at room temperature with significant edge rounding, large rates compared to laboratory estimates, and activation energy equal to that of molecule detachment at kink sites. A different kinetic regime is predicted for grains with typical macroscopic sizes or for high temperatures, in which pit nucleation at flat surfaces and step retreat lead to more uniform dissolution. The extrapolation of high temperature simulation data to room temperature gives dissolution rate 0.3 - 1.4 μ mol/(m2s) and activation energy 64 ± 3 kJ/mol for macroscopic grains with various densities of surface steps. This rate agrees with the smallest values obtained in a recent compilation of laboratory data in alkaline conditions and the activation energy agrees with laboratory estimates. Grains with high densities of kink sites are shown to dissolve with rates ∼ 10 1 - 10 2 times larger; these estimates are used to predict the contribution of dislocations and explain the largest values of that compilation.

中文翻译：

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模拟中性和碱性溶液中方解石溶解的动力学

摘要 使用动力学蒙特卡罗模拟和缩放方法，我们描述了在中性到碱性溶液中远非平衡的方解石溶解，以及从表面的分子脱离到晶粒的范围的尺度。热激活模型的参数通过在原子力显微镜工作中测量的阶地台阶的速度和单层凹坑的密度来校准。对纳米尺寸晶粒的应用表明，它们在室温下溶解，边缘显着变圆，与实验室估计相比具有较大的速率，并且活化能与在扭结位置的分子分离时的活化能相等。对于具有典型宏观尺寸或高温的晶粒，预测了不同的动力学状态，其中平坦表面的凹坑形核和阶梯后退导致更均匀的溶解。将高温模拟数据外推至室温，对于具有各种表面台阶密度的宏观晶粒，溶解速率为 0.3 - 1.4 μmol/(m2s)，活化能为 64 ± 3 kJ/mol。该速率与最近在碱性条件下的实验室数据汇编中获得的最小值一致，活化能与实验室估计值一致。具有高密度扭结点的颗粒溶解速度大约是 10 1 - 10 2 倍；这些估计用于预测错位的贡献并解释该汇编的最大值。对于具有各种表面台阶密度的宏观晶粒，4 μ mol/(m2s) 和活化能为 64 ± 3 kJ/mol。该速率与最近在碱性条件下的实验室数据汇编中获得的最小值一致，活化能与实验室估计值一致。具有高密度扭结点的颗粒溶解速度大约是 10 1 - 10 2 倍；这些估计用于预测错位的贡献并解释该汇编的最大值。对于具有各种表面台阶密度的宏观晶粒，4 μ mol/(m2s) 和活化能为 64 ± 3 kJ/mol。该速率与最近在碱性条件下的实验室数据汇编中获得的最小值一致，活化能与实验室估计值一致。具有高密度扭结点的颗粒溶解速度大约是 10 1 - 10 2 倍；这些估计用于预测错位的贡献并解释该汇编的最大值。具有高密度扭结点的颗粒溶解速度大约是 10 1 - 10 2 倍；这些估计用于预测错位的贡献并解释该汇编的最大值。具有高密度扭结点的颗粒溶解速度大约是 10 1 - 10 2 倍；这些估计用于预测错位的贡献并解释该汇编的最大值。