Transport of post-transition metals in hydrothermal fluids: thermodynamics from first-principles

自青铜时代以来，金属锡和铅一直具有至关重要的经济价值。近年来，周期表上的相邻元素Ga和In由于其在电子设备中的使用而变得需要。Sn、Pb、Ga和In一起被称为后过渡金属。这些元素具有不寻常的电子结构，它们的地球化学行为与Cu和Zn等金属不同。为了满足未来的需求，我们需要找到和评估这些金属的新资源。大多数金属矿床通常是由地壳深处的热液流体形成的。这种流体能够从大量岩石中提取微量金属，并将其浓缩成溶液。当热溶液冷却、减压或与矿物反应时，它们随后将溶解的金属沉淀为硫化物或氧化物矿物并形成矿床。然而，这种情况发生的化学过程通常是一个谜。高温高压下热液流体化学的实验研究是非常困难的。然而，我们可以使用基于量子力学的计算模拟来深入了解热液流体中发生的事情。我们现在可以确定金属是如何与溶解的配体如Cl-、HS-络合的，并完全从第一性原理推导出这些反应的平衡常数。这打开了一扇大门，对地壳中流体的化学和作用有了新的认识。本文提出的工作将这些方法应用于后过渡金属络合物与配体，如Cl-，HS-和F开发的矿物溶解度，可用于了解这些金属的矿床形成的热力学模型。

Since the Bronze age, the metals Sn and Pb have been of crucial economic importance. In recent years, the neighbouring elements on the periodic table, Ga and, In have come into demand because of their use in electronic devices. Together, Sn, Pb, Ga and In are referred to as the post-transition metals. These elements have unusual electronic structures and their geochemical behaviour is different from metals such as Cu and Zn. To meet future demand, we will need to locate and assess new resources of these metals. Most ore deposits of metals are usually formed by hydrothermal fluids deep in the Earth's crust. Such fluids are able to extract trace metals from large volumes of rock and concentrate them into solutions. As the hot solutions cool, depressurise or react with minerals, they will subsequently precipitate dissolved metals as sulphide or oxide minerals and form ore deposits. However, the chemical processes by which this happens is usually a mystery. Experimental investigations of the chemistry of hydrothermal fluids at high temperatures and pressures are very difficult. However, we can gain a great deal of insight on what happens in hydrothermal fluids using computational simulations based on quantum mechanics. We can now determine how metals are complexed by dissolved ligands such as Cl-, HS- and derive equilibrium constants for these reactions entirely from first-principles. This opens the door to vast new insights on the chemistry and role of fluids in the Earth's crust. The work proposed here will apply these methods to the post-transition metal complexes with ligands such as Cl-, HS- and F to develop a thermodynamic model of mineral solubilities that can be used to understand how ore-deposits of these metals form.