Antimony weathering products in mine wastes: A case study in Pezinok (Slovakia)

锑被列为优先污染物;已知它有毒，而且可能致癌。然而，与它的地球化学表亲砷元素相比，这种污染物很少受到关注。在废弃的或活跃的矿区，原生锑矿物（主要是辉锑矿，Sb 2S 3）风化形成锑氧化物，富锑水合氧化铁，或释放锑到环境中。在这里，我提出了一个细致的研究，这一过程中的矿物产品相结合的互补散装和微量分析技术。我们研究的样品来自斯洛伐克一个废弃锑存款Pezinok附近的两个废物蓄水池。样品取自几个钻孔，代表了整个风化剖面的蓄水池，并在一个非常详细的调查方面的形态和迁移的As。在拟议的工作中，我们将确定通过X射线衍射和光学显微镜的钻孔样品的体矿物学。然后，通过电子探针分析选定的晶粒的化学成分，通过微衍射分析其晶体结构，并通过微X射线吸收（在Sb L，边缘）分析Sb的氧化态。合适的散装样品也将进行研究，这些是水合氧化铁材料与高达28.3重量%的As 2 O 5和2.7重量%的Sb。我们将进行大量的X射线吸收（XAS）实验在Sb K边缘，以确定这些样品中的Sb的局部环境。特别感兴趣的是协会或竞争的As和Sb的吸附位点时，它们同时发生在大量的。为了补充XAS实验并改善Sb形态的信息，我们还将尝试进行121 Sb穆斯堡尔实验。在项目结束时，我们将拥有一个完整的数据集的化学成分，晶体结构（或缺乏）的最重要的锑风化产物和化学状态的锑在其中。目前缺少此类信息，因为现有研究没有同时使用所有技术，或者从地球化学角度（例如，通过顺序提取）。

Antimony is classified as a priority pollutant; it is known to be toxic and probably also carcinogenic. Nevertheless, little attention is paid to this pollutant in comparison with its geochemical cousin, the element arsenic. At abandoned or active mining sites, the primary Sb minerals (mostly stibnite, Sb2S3) weather to form Sb oxides, Sb-rich hydrous ferric oxide, or to release Sb into the environment. Here I propose a meticulous study of the mineral products of this process by a combination of complementary bulk and micro-analytical techniques. The samples for our study come from two waste impoundments near an abandoned Sb deposit Pezinok in Slovakia. The samples were taken from several boreholes, representing the entire weathering profile of the impoundments, and investigated in a great detail with respect to the speciation and migration of As. In the proposed work, we will determine the bulk mineralogy of the borehole samples by X-ray diffraction and optical microscopy. Selected grains will be then analyzed by an electron microprobe for their chemical composition, micro-diffraction for their crystal structure, and micro-X-ray absorption (at the Sb L,,, edge) for the Sb oxidation state. Suitable bulk samples will also be studied; these are hydrous ferric oxide materials with up to 28.3 wt% As2O5 and 2.7 wt% Sb. We will perform bulk X-ray absorption (XAS) experiments at the Sb K edge to determine the local environment of Sb in these samples. Of particular interest is the association or competition of As and Sb for adsorption sites when they occur simultaneously in large amounts. To complement the XAS experiments and to improve the information on Sb speciation, we will also attempt to carry out bulk 121Sb Mössbauer experiments. In conclusion of the project, we will hold a complete data set on the chemical composition, crystal structure (or lack thereof) of the most important Sb weathering products and the chemical state of Sb within them. Such information is currently missing because the existing studies did not use all techniques simultaneously or they focused on the speciation of Sb from a geochemical point of view (e.g., by sequential extractions).