论文部分内容阅读
采用仪器中子活化分析法(INAA)测定了华北晚古生代石炭纪-二叠纪58个煤及煤层夹矸和顶底板样品的稀土元素含量。通过对稀土元素地球化学特征的研究表明,华北晚古生代煤中稀土元素总量绝大多数变化于30×10~(-6)～80×10~(-6)之间,平均为56×10~(-6),属正常水平;靠近物源区的华北北部太原组比远离物源区并且受陆表海影响的华北南部太原组更加富集稀土元素;稀土元素总量还受煤中灰分所影响,与煤的灰分产率成正相关关系,尤其与<2μm的粘土矿物密切相关。这证明稀土元素在煤中的聚集过程中陆源物质起重要作用。煤中LREE明显富集,LREE/HREE一般在2～8之间,与高灰低硫煤相比,低灰高硫煤中其比值较低,该比值在顶底板岩石中达12以上,在黄铁矿结核中最高,达21,表明受海水影响的还原环境中HREE与有机质更具亲和力。稀土元素中普遍存在Eu亏损现象。在整个华北地区,正常煤层内的稀土元素分布模式十分相似,表明在华北晚古生代石炭纪-二叠纪成煤期间,保持有相对稳定的陆源物质供应。在低灰煤中,稀土元素主要由细粒的吸附灰分和生物灰分所承载,有机物质同时也吸附了一定比例的REE。受岩浆活动影响的煤其稀土元素总量最高,岩浆物质加入可以促使煤中稀土元素增加,并会导致稀土元素分布模式出现异常,同时常伴随有如U、W和A
The content of rare earth elements (REE) in 58 coal and coal seams and roof and floor samples from the Late Paleozoic in North China was measured by instrumental neutron activation analysis (INAA). The study on the geochemical characteristics of rare earth elements shows that the vast majority of the total amount of rare earth elements in coal from the Late Paleozoic in North China changed from 30 × 10 -6 to 80 × 10 -6 with an average of 56 × 10 ~ (-6), which belongs to the normal level. The Taiyuan Formation in North China and North China near the provenance area is more enriched in rare earth elements than the Taiyuan Formation in the southern part of North China, which is far away from the provenance area and influenced by land surface sea. The total amount of rare earth elements is also affected by ash in coal , And coal ash production rate is a positive correlation, especially with <2μm clay minerals are closely related. This proves that terrestrial materials play an important role in the process of the aggregation of rare earth elements in coal. LREE in coal is obviously enriched with LREE / HREE ranging from 2 to 8 generally. Compared with high-ash and low-sulfur coal, the ratio of LREE to low-ash and high-sulfur coal is relatively low, which is above 12 in top and bottom rock. Pyrite nodules in the highest, up to 21, indicating that HREE is more affinity with organic matter in the reducing environment affected by seawater. Eu depletion is common in rare earth elements. Throughout North China, the distribution pattern of rare earth elements in normal coal seams is very similar, indicating that during the Late Paleozoic Carboniferous-Permian coal formation in North China, a relatively stable terrigenous supply was maintained. In low-ash coal, rare earth elements are mainly carried by fine ash adsorbed ash and bio-ash, and organic matter also adsorbs a certain proportion of REE. Coal affected by magmatic activity has the highest total amount of rare earth elements. The addition of magma can promote the increase of rare earth elements in coal and lead to the abnormal pattern of rare earth elements distribution, often accompanied by such as U, W and A