Kinetics of Dissolution and Crystal Growth of Silicates and Aluminosilicates in Aqueous Soultions at Low Temperatures

进一步研究了pH、温度、离子强度、催化/抑制和吉布斯自由能对硅酸盐和铝硅酸盐溶解和沉淀动力学的影响。我们将使用表面分析技术（特别是XPS， AES， SEM， AFM）检查反应矿物的表面，当结合使用流动反应器和柱式反应器从溶液化学中确定的速率时，将提供表面反应机制的信息。在较低温度下使用AFM和在热液温度下使用新的光学干涉测量技术对反应的矿物表面进行原位观察，将为传统动力学实验和非原位表面分析提供桥梁。关于矿物-流体相互作用动力学的新实验发现将与我们小组所做的广泛的分子物理学研究相结合，以确定控制地球化学过程的原子动力学。我们的实验工作继续在描述主要岩石形成硅酸盐和铝硅酸盐的溶解和沉淀速率作为G的函数方面处于领先地位，并且是第一个测量比石英更复杂的相的沉淀速率。在我们之前的工作中开发的非平凡全速率定律被证明是非常重要的，它成功地将实验速率数据应用于模拟现场案例，例如使用精确的二维水动力流体流动模型的委内瑞拉皮鸡果铝土矿床。随着本文所提出的工作的继续进行，实验、理论和模型的耦合将产生第一个从原子水平到野外环境的水岩相互作用的完全定量的物理和化学模型，这些环境包括动态沉积盆地的成岩作用或大型铝土矿床的化学演化。

Lasaga 9526794 It is proposed to continue the studies of the experimental determination of the dissolution and precipitation kinetics of silicates and aluminosilicates as functions of pH, temperature, ionic strength, catalysis/inhibition and the Gibbs Free energy of reaction. We will examine the surfaces of the reacted minerals using surface analytical techniques (XPS, AES, SEM, AFM in particular), which when combined with rates determined from solution shemistry using flow-through and column reactors will provide information on surface reaction mechanisms. In situ observations of reaacting mineral surfaces, using the AFM at lower temperature and new optical interferometric techniques at hydrothermal temperatures, will provide a bridge between the conventional kinetics experiments and ex-situ surface analysis. The new experimental findings on the kinetics of mineral-fluid interactions will be coupled with extensive molecular physics studies done in our group to ascertain the atomic dynamics governing geochemical processes. Our experimental work continues to lead the way in describing both dissolution and precipitation rates of major rock-forming silicates and aluminosilicates as a function of G, as well as being the first to measure precipitation rates in phases more complex than quartz. The non-trivial full rate laws that have been developed in our prior work are proving to be very important in successfully applying experimental rate data to model field cases, such as the Pijiguaos, bauxite deposit in Venezuela using accurate two-dimensional hydrodynamic fluid flow models. With the continuing work proposed here, the coupling of experiment, theory and models should result in the first completely quantitative physical and chemical model of water-rock interactions from the atomic level to the field setting under a wide set of geological environments including diagenesis in a dynamic sedimentary basin or the chemical evolution in a major bauxite deposit.