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.

燃烧六价铀(铀酰)矿物普遍存在于铀矿床的氧化部分，对于了解铀矿床中水-岩相互作用、环境中鳗系元素的活动性、铀矿尾矿和选矿尾矿的风化以及地质储存库中乏核燃料的变化具有重要意义。这项研究将侧重于前寒武纪铀矿床风化部分以及利用这些资源产生的风化尾矿中出现的铅铀酰水合物矿物。这些结构复杂的矿物含有几种不同的铀酰多面体，铅阳离子和水分子位于层间位置。初步工作表明，这些矿物在某些结构类型中表现出相当大的成分变化，并导致假设，铀酰多面体片层中的阴离子取代可能是允许层间含量变化的电荷平衡机制。将利用广泛的结晶学研究、显微探针分析和矿物类似物的合成来研究铅铀酰水合物矿物Vandriesscheite、Farierite、Curite、Richeite、Sayite和wlsdorfite。这些研究将提供这些复杂矿物的晶体化学可变性的细节。研究结果将用于扩展铀酰矿物的结构层次，并加深对这些矿物和其他低温矿物的结构与共生关系的理解。