Environmental mobility of tin

锡的环境流动性

• 批准号: 450493115
• 负责人: Professor Dr. Juraj Majzlan, Ph.D.
• 金额: --
• 依托单位: Lehrstuhl Allgemeine und Angewandte Mineralogie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2020
• 资助国家: 德国
• 起止时间: 2019-12-31 至 2022-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/450493115?language=en
• 关键词: Environmental; mobility; tin

Environmental mobility of tin will be evaluated by the means of i) thermodynamic measurements and modeling, ii) chemical and structural investigation on weathering of primary tin sulfides in field settings, and iii) isotopic variations of Sn between primary sulfides and secondary oxidic materials. The thermodynamic measurements will consist of solution calorimetry (with resulting enthalpies of formation) and relaxation calorimetry (entropies) on a suite of tin hydroxides of the schoenfliesite group, □2(BSn)(OH)6, with B = Ca, Fe2+, Mg, Mn2+, Zn, Cu, and Fe3+. The data will be used to calculate solubility of these minerals under variable pH and to evaluate the saturation state of mine drainage waters with respect to these minerals. Weathered tin sulfides will be collected at selected field sites (historical mines) and investigated by polarized light microscopy, electron microprobe, micro-X-ray diffraction or transmission electron microscopy, in order to determine the nature of the secondary tin minerals. Limited preliminary work suggests that they may be close to the tin hydroxides of the schoenfliesite group. Weathering products of the associated primary minerals (e.g., pyrite, arsenopyrite) will be also analyzed for their Sn content, in order to evaluate tin mobility at the historical mining sites. Isotopic variations in Sn between the primary sulfides and secondary oxidic minerals have the potential to indicate geochemical processes in which tin is mobile and lost. Isotopic differences between the two reservoirs would indicate mobility of tin, even if not captured by the mineralogical investigation alone. The aim of this work is to predict mobility of tin at mining sites, in the presence of other metallic elements (Fe, Cu, Zn) which are able to form tin hydroxide minerals.

锡的环境流动性将通过以下方式进行评估：i）热力学测量和建模，ii）野外环境中原生锡硫化物风化的化学和结构研究，iii）原生硫化物和次生氧化物之间Sn的同位素变化。热力学测量将包括对一组软钾矾族的锡氢氧化物□2（BSn）（OH）6（其中B = Ca、Fe 2+、Mg、Mn 2+、Zn、Cu和Fe 3+）的溶液量热法（以及由此产生的生成焓）和弛豫量热法（熵）。这些数据将用于计算这些矿物质在可变pH值下的溶解度，并评估矿井排水沃茨相对于这些矿物质的饱和状态。风化的锡硫化物将在选定的现场（历史矿山）收集，并通过偏振光显微镜、电子显微探针、微X射线衍射或透射电子显微镜进行研究，以确定次生锡矿物的性质。有限的初步工作表明，它们可能接近于软锰矿族的氢氧化锡。伴生原生矿物的风化产物（例如，此外，还将分析锡矿（黄铁矿、毒砂）的锡含量，以评估历史采矿地点的锡流动性。原生硫化物和次生氧化物矿物之间Sn的同位素变化具有指示锡移动的和损失的地球化学过程的潜力。两个储层之间的同位素差异将表明锡的流动性，即使不是由矿物学调查单独捕获。这项工作的目的是预测流动性的锡在采矿现场，在其他金属元素（铁，铜，锌）的存在下，能够形成锡氢氧化物矿物。