The nature of micro- and nanocrystalline weathering products of sulfidic ores rich in As and Sb

富含砷(As)和锑(Sb)的硫化矿石通常被开采，是许多重要金属、类金属和原材料的来源。采矿废物，无论是历史上、最近产生的，还是目前产生的，都是一个主要的环境负荷，尽管采矿和加工技术正在稳步改进。硫化矿石及其伴生的采矿废弃物与大气和水圈接触后，会发生风化、转化，并可能对环境造成污染。在这里，我建议研究富As和Sb矿石的精选风化产物的晶体结构和晶体化学。它们很常见，通常控制有毒类金属和金属的流动性和生物利用度。然而，它们的性质尚不清楚。在这项提议中，我们将针对Fe(III)-As(V)-S(VI)-H2O和(铜、锌、银、铋、铁)-Sb(V)-As(V)-H2O系统中的相。也就是说，我们将研究来自ROTGülden(奥地利)的砷酸铁钾石、方沸石和一系列以前未知的相。在后一系统中，我们将考察四方铅锌矿的风化产物。除了详细的光学显微镜和电子探针工作外，工作的重点是衍射技术：高分辨率粉末X射线衍射和电子进动衍射。特别是后一种方法，将被用来破译纳米级风化产物混合物的晶体结构。该项目将是纳米级自然风化产品的基准研究。虽然透射式电子显微镜在环境研究中已被广泛使用，但解决复杂纳米混合物中所有相的晶体结构的可能性确实是一场革命。它将为风化产物及其转化序列的详尽和完整的表征打开大门。

Sulfidic ores rich in arsenic (As) and antimony (Sb) are commonly exploited and serve as a source of many important metals, metalloids, and raw materials. Mining waste, either historical, recent, or currently produced, represents a major environmental load, even though the mining and processing technologies are steadily improving. Upon contact with atmosphere and hydrosphere, the sulfidic ores and the associated mining wastes weather, transform, and may pollute the environment. Here I propose to study crystal structures and crystal chemistry of selected weathering products of ores rich in As and Sb. They are common and often control the mobility and bioavailability of the toxic metalloids and metals. Yet, their nature is not known. Within this proposal, we will target phases from the systems Fe(III)-As(V)-S(VI)-H2O and (Cu,Zn,Ag,Bi,Fe)-Sb(V)-As(V)-H2O. Namely, we will study the ferric arsenates kankite, zykaite, and a suite of previously unknown phases from Rotgülden (Austria). From the latter system, we will inspect weathering products of tetrahedrite-tennantite ores. In addition to detailed optical microscopy and electron microprobe work, the focus of the work is in the diffraction techniques: high-resolution powder X-ray diffraction and electron precession diffraction. The latter method, in particular, will be used to decipher the crystal structure of the nanosized mixtures of weathering products. This project will be a benchmark study of nanosized natural weathering products. Although transmission electron microscopy has been used commonly in environmental studies, the possibility to solve crystal structures of all phases in a complex nanomixture is truly a revolution. It will open the door to an exhaustive and complete characterization of the weathering products and their transformation sequences.