Abstract The reaction kinetics of gypsum dissolution are important for establishing an optimum gypsum content in portland cement. In this paper, the temperature dependence of dissolution rates was measured by tracking changes in solution composition and surface area with time. The rate coefficient increases with temperature and the specific surface area decreases with ongoing dissolution. The dissolution rate depends on the solution's saturation index to an exponent of approximately 1.5. The apparent activation enthalpy is approximately 34 kJ mol−1, independent of saturation index and surface area, suggesting that dissolution is controlled by surface reaction rather than mass transport. The activation enthalpy is interpreted as the energy required to cooperatively break all the ionic bonds at occupied kink sites of the gypsum-water interface. Activation enthalpies similar in magnitude have been reported for other calcium salts, which may indicate that all of these processes involve breaking ionic calcium-oxygen bonds of similar strengths.

中文翻译：

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石膏溶解速率的温度依赖性

摘要 石膏溶解的反应动力学对于确定硅酸盐水泥中的最佳石膏含量很重要。在本文中，通过跟踪溶液组成和表面积随时间的变化来测量溶解速率的温度依赖性。速率系数随温度增加而比表面积随着溶解的进行而减小。溶解速率取决于溶液的饱和指数，指数约为 1.5。表观活化焓约为 34 kJ mol-1，与饱和指数和表面积无关，表明溶解受表面反应而不是传质控制。活化焓被解释为在石膏-水界面的占据的扭结点处合作破坏所有离子键所需的能量。