Investigation of the Crystal Chemistry of Pb Uranyl Oxide Hydrate Minerals Using a CCD-Based X-Ray Area Detector

使用基于 CCD 的 X 射线面探测器研究 Pb 氧化铀水合物矿物的晶体化学

• 批准号: 9804723
• 负责人: Peter Burns
• 金额: $ 9.81万
• 依托单位: University of Notre Dame
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-10-01 至 2001-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9804723&HistoricalAwards=false
• 关键词: Investigation; Crystal; Chemistry; Pb; Uranyl

9804723BurnsHexavalent uranium (uranyl) minerals are common in the oxidized portions of U deposits, and are important for understanding water-rock interactions in U deposits, the mobility of actinides in the environment, the weathering of U mine and mill tailings, and the alteration of spent nuclear fuel in a geological repository. This study will focus on Pb uranyl oxide hydrate minerals that occur in the weathered portions of Precambrian U deposits, as well as in weathered mine tailings that result from the utilization of such resources. These structurally complex minerals contain several different sheets of uranyl polyhedra, with Pb cations and water molecules located in interlayer positions. Preliminary work has demonstrated that these minerals show considerable compositional variability within some of the structure types, and led to the hypothesis that anionic substitution in the sheets of uranyl polyhedra may be the charge-balancing mechanism that permits variation of the interlayer content. The Pb uranyl oxide hydrate minerals vandendriesscheite, fourmarierite, curite, richetite, sayrite, and wlsendorfite will be investigated using extensive crystallographic studies, microprobe analysis, and the synthesis of mineral analogues. These studies will provide the details of the crystal-chemical variability of these complex minerals. The results of the investigations will be used to extend the structural hierarchy of uranyl minerals, and to develop an understanding of the relationship between the structures and paragenesis of these and other low-temperature minerals.

9804723Burnshexavalent铀（铀酰）矿物质在U沉积物的氧化部分中很常见，对于理解U沉积物中的水摇滚相互作用至关重要，阳离子的迁移率在环境中的迁移率，U地雷和磨坊量的风化以及在地质恢复中消费的核燃料的改变。这项研究将重点关注在前寒武纪U沉积物的风化部分以及由于利用此类资源而导致的风化矿山尾矿中发生的PB铀酰氧化物水合物矿物质。这些结构上复杂的矿物质包含几片不同的铀酰聚乙烯，PB阳离子和水分子位于层间位置。初步工作表明，这些矿物质在某些结构类型中显示出很大的组成变异性，并提出了以下假设：铀酰聚合物纸中的阴离子取代可能是允许层中层含量变化的电荷平衡机制。将使用广泛的晶体学研究，微探针分析和矿物类似物的合成研究，将研究PB氧化物水合物矿物矿物vandendriesscheite，Fourmarierite，Curite，Richite，Sayrite和Wlsendorfite。这些研究将提供这些复杂矿物质的晶体化学变异性的细节。研究结果将用于扩展铀酰矿物的结构层次结构，并发展对这些结构与这些低温矿物质的结构之间的关系的理解。