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

富含砷（As）和锑（Sb）的硫化矿被广泛开发，是许多重要金属、类金属和原材料的来源。采矿废料，无论是历史的、最近的还是目前产生的，都是一个主要的环境负担，尽管采矿和加工技术正在稳步改进。硫化矿石及其伴生矿渣与大气、水圈接触后，会发生风化、变质，并可能污染环境。本文拟对富砷、锑矿风化产物的晶体结构和晶体化学进行研究。富砷、锑矿风化产物是一种常见的、经常控制有毒类金属和金属的迁移性和生物利用度的风化产物。然而，它们的性质尚不清楚。在这个提议中，我们将从系统Fe(III)-As(V)-S(VI)-H2O和(Cu,Zn,Ag,Bi,Fe)-Sb(V)-As(V)-H2O中瞄准相。也就是说，我们将研究铁砷酸盐kankite， zykaite，和一套以前未知的相从rotg<e:1> lden（奥地利）。从后一体系出发，考察四面体-钛矿的风化产物。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，将用于破译纳米级风化产物混合物的晶体结构。本项目将成为纳米级自然风化产品的标杆性研究。虽然透射电子显微镜已广泛用于环境研究，但在复杂纳米混合物中解决所有相晶体结构的可能性确实是一场革命。它将为详尽和完整地表征风化产物及其转化序列打开大门。

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.