黔西上二叠统宣威组粘土岩中铌的赋存状态研究

近年来，在黔西玄武岩古风化壳型沉积岩(宣威组底部粘土岩)中发现Nb富集现象，Nb含量在数百μg/g。按我国风化壳类型Nb矿床所要求的工业品位(160~200μg/g) 预测，贵州西部潜在铌资源量在100万吨以上。该区域Nb矿化层分布广，被视为一种新型Nb资源。该类型Nb资源具有重要的理论意义和开发利用潜力。已有研究探讨了铌的地球化学特征、物源、富集条件等，缺少专门针对铌赋存状态的系统研究。虽然发现部分含Nb钛矿物，但钛矿物含Nb量，无法与整个样品Nb的总量匹配，此外，主要组成矿物粘土矿物是否含有吸附态的Nb等科学问题缺少深入研究。本项目拟从Nb和粘土矿物的吸附机理、含铌矿物矿物学特征与Nb类质同象替换之间的联系、分选富集副矿物及纳米细微矿物中查找含Nb矿物等方面着手，借助EPMA、FIB、SEM-SAED、TEM-EDS、LA-ICP-MS等微区分析方法，开展系统研究，查明Nb的赋存状态与分布规律。

Recently, anomalous enrichment of rare element NIOBIUM was found in the claystones at bottom of Late Permian Xuanwei Strata, Western Guizhou, southwest China. According to the National standard for Nb deposit of type of weathering crust, 160~200μg/g for (Nb,Ta)2O5 in the sample can meet its industrial requirements. Thus, it is predicted that the resource of Nb in Western Guizhou can be more than one million tonnes of Nb2O5. Geochemical characteristics, origin and enrichment environmental conditions of Nb have been widely reported, while seldom research focus on the occurrence statements of Nb in the mentioned claystones. Ti-bearing minerals in the clay rock was considered the source of Nb, however, it is known that Ti-bearing minerals might not the only phase which provides Nb, especially for the samples that contain very less titanium and high niobium. More systematic research works are necessary and more attentions should be paid for that. This project would conduct researches on the adsorption mechanism and relationship between clay minerals and niobium, mineralogical characteristics of Nb-bearing mineral and isomorphic replacement. Relative accessory minerals and nano-scaled fine minerals in the claystones would be enriched or separated using chemical treatment for identification of Nb- containing or not. Modern analytical methods, such as EPMA, FIB, SEM-SAED, TEM-EDS and LA-ICP-MS, would be used for the research process to release the distribution and occurrence state of niobium in the clay rocks from Late Permian Xuanwei Strata, Western Guizhou.