SusChEM: Indium in Magmatic-Hydrothermal Systems

21世纪的新技术，从液晶显示器到触摸屏和太阳能电池，都涉及到一些金属的使用，而这些金属在几十年前还不是地球上的主流资源。人类的创新为铟带来了新的用途，包括生产氧化铟锡（ITO），这是一种既导电又透明的物质。这些特性允许它作为智能手机、平板电脑和相关设备的触摸屏的主动组件使用。因此，从上世纪90年代到本世纪头十年中期，对铟的需求增长了三倍，而ITO在很大程度上要对这种需求增长负责。本文提出的研究不仅将提高我们对地球地壳中铟分布的认识，而且将有助于勘探新的含铟矿石，从而有助于为该国未来的铟需求提供帮助。铟的主要来源包括块状硫化物矿床、脉状矿床（包括与花岗岩有关的矿脉）和其他与花岗岩有关的矿床。铟最常从闪锌矿中回收，闪锌矿是一种硫化锌矿物。作为这项工作的一部分，将进行实验，以填补我们在次火山岩浆系统的结晶、水相和熔融相中铟分布的知识的关键空白，以及在成矿条件下铟与闪锌矿结合的热力学。研究结果将允许定量估计岩浆热液效率，铟可以从岩浆中取出，并纳入含闪锌矿的矿石。拟议的研究将允许勘探人员和研究人员测试关于高温含铟矿石形成的假设。本项目由NSF可持续化学、工程和材料（SusChEM）计划资助。

New technologies for the 21st century, with applications from LCD displays to touch screens and solar cells, involve the use of some metals that were not mainstream Earth resources just a few decades ago. Human innovation has led to new uses for indium, including the production of indium tin oxide (ITO), a substance that is both electrically conductive and optically transparent. These properties permit its use as the active component in the touch screens of smart phones, tablets, and related devices. As a result, the demand for indium increased three-fold from the 1990s to the mid-2000s, and ITO has been responsible for much of this increased demand. The research proposed herein will not only improve our understanding of the distribution of indium in the crust of the Earth, but will aid in the exploration for new indium-bearing ores, and thereby, help provide for the future indium needs of the country.The primary sources for indium include massive sulfide deposits, vein deposits including granite-related veins, and other granite-related deposits. Indium is most commonly recovered from sphalerite, a zinc sulfide mineral. As part of this work, experiments will be performed to close critical gaps in our knowledge concerning the distribution of indium among the crystalline, aqueous, and molten phases of sub-volcanic magmatic systems, as well as the thermodynamics of the incorporation of indium into sphalerite under ore-forming conditions. Results of the research will permit quantitative estimates of the magmatic-hydrothermal efficiency with which indium can be removed from magmas, and be incorporated into sphalerite-bearing ores. The proposed research will permit explorationists and researchers to test hypotheses for the formation of high-temperature indium-bearing ores. This project is supported via the NSF FY14 Sustainable Chemistry, Engineering, and Materials (SusChEM) initiative.