Galindo C, Mougin L, Fakhi S, Nourreddine A, Lamghari A, Hannache H
Institut Pluridisciplinaire Hubert Curien, 23, rue du Loess BP28, 67037 Strasbourg Cedex 2, France.
J Environ Radioact. 2007;92(1):41-54. doi: 10.1016/j.jenvrad.2006.09.005. Epub 2006 Nov 13.
Attention has been focused recently on the use of Moroccan black oil shale as the raw material for production of a new type of adsorbent and its application to U and Th removal from contaminated wastewaters. The purpose of the present work is to provide a better understanding of the composition and structure of this shale and to determine its natural content in uranium and thorium. A black shale collected from Timahdit (Morocco) was analyzed by powder X-ray diffraction and SEM techniques. It was found that calcite, dolomite, quartz and clays constitute the main composition of the inorganic matrix. Pyrite crystals are also present. A selective leaching procedure, followed by radiochemical purification and alpha-counting, was performed to assess the distribution of naturally occurring radionuclides. Leaching results indicate that 238U, 235U, 234U, 232Th, 230Th and 228Th have multiple modes of occurrence in the shale. U is interpreted to have been concentrated under anaerobic conditions. An integrated isotopic approach showed the preferential mobilization of uranium carried by humic acids to carbonate and apatite phases. Th is partitioned between silicate minerals and pyrite.
最近，人们的注意力集中在使用摩洛哥黑色油页岩作为生产新型吸附剂的原料，以及将其应用于从受污染废水中去除铀和钍。本工作的目的是更好地了解这种页岩的组成和结构，并确定其铀和钍的天然含量。对从摩洛哥蒂马赫迪特采集的黑色页岩进行了粉末X射线衍射和扫描电子显微镜技术分析。发现方解石、白云石、石英和粘土构成了无机基质的主要成分。也存在黄铁矿晶体。进行了选择性浸出程序，随后进行放射化学纯化和α计数，以评估天然存在的放射性核素的分布。浸出结果表明，238U、235U、234U、232Th、230Th和228Th在页岩中有多种赋存方式。铀被解释为在厌氧条件下富集。一种综合同位素方法表明，腐殖酸携带的铀优先迁移到碳酸盐和磷灰石相中。钍则分布在硅酸盐矿物和黄铁矿之间。
