煤矿区中铅的环境地球化学研究

发布时间：2018-04-22 11:46

本文选题：铅 + 煤　；参考：《中国科学技术大学》2015年博士论文

【摘要】：自1970年以来铅由于其潜在环境危害性及生物累积性引起了人们广泛的关注和研究。铅,作为煤中常见的微量元素之一,在煤炭的开采、存放、选洗及燃烧过程中,大量释放到环境中,从而给环境带来危害。本文在研究煤中铅的丰度与分布、赋存状态、富集成因的基础上,以安徽淮南矿区为例,系统地研究了煤矿区环境中铅的地球化学行为。在充分调研国内外文献的基础上,采用加权均值统计法,计算得出中国煤中铅的平均值为13.0μg/g,不同成煤区域中Pb的含量差异较大,根据煤中Pb含量的不同,划分出低铅煤(Pb20μg/g),中铅煤(20μg/gPb40μg/g),高铅煤(Pb40μg/g)三个不同的分级标准；且煤中的铅含量与成煤时代和煤级密切相关,其中晚三叠世煤和高煤阶煤中的铅含量较高,推测与区域的地球化学差异和后期的地质演化及岩浆热液活动有关；煤中的铅主要与硫化物矿物相结合,尤以方铅矿形态存在较为常见；在煤炭燃烧或者热解的过程中,煤中铅部分迁移释放到大气当中,部分铅会富集在固体残留物(底灰和飞灰)中。以安徽淮南矿区为例,探讨了煤炭开采过程中中铅的环境地球化学。在分析Pb的矿区表生环境中的含量分布基础上,对Pb的环境危害进行评价分析。该煤矿区土壤中铅的平均含量为28.3mg/kg,与煤矸石中的铅含量相当(29.2mg/kg);煤矸石可以通过雨水淋溶到土壤环境中。在矿区土壤中采集的动物样品(蚯蚓)中Pb的含量较高,而矿区塌陷湖水样中的含量较低,这说明铅通过土壤迁移到蚯蚓体内,而水体受其影响较小。对矿区农作物中Pb的含量研究发现,小麦根部的含量高于在茎、叶、壳中的含量,在籽实中富集,且超出了国家对食品中铅含量的限定(GB2762-2012)。在水稻和黄豆体内,大部分铅被固定在根部,其次是茎和壳。在三种作物当中,小麦对铅具有更高的吸收能力。鉴于鲫鱼肉中的铅含量水平在污染物限量范围内,塌陷湖水体中养殖的鲫鱼被认为是适于食用的。通过对每日摄入量和总危害商的计算,证明了矿区居民食用矿区生产的农产品暂时是没有较大的风险的。
[Abstract]:Lead has attracted extensive attention and research since 1970. Lead, as one of the most common trace elements in coal, has been released into the environment in the process of coal mining, storage, washing and combustion. This paper studies the abundance and distribution of lead in coal. Based on the occurrence and enrichment causes, the geochemical behavior of lead in coal mining area is systematically studied in Anhui Huainan mining area as an example.
On the basis of full investigation and investigation of domestic and foreign literature, the average value of lead in Chinese coal is 13 g/g, and the content of Pb in different coal forming regions is different. According to the different content of Pb in coal, three different grades of low lead coal (Pb20 mu g/g), medium lead coal (20 u g/gPb40 mu g/g), and high lead coal (Pb40 u g/g) are classified. The lead content in coal is closely related to the coal age and coal grade, in which the lead content in the late three strata and the high rank coal is higher, which is presumed to be related to the regional geochemical differences, the later geological evolution and the magmatic hydrothermal activity; the lead in the coal is mainly combined with the sulfide minerals, especially the galena form. In coal combustion or pyrolysis, some of the lead in the coal migrate to the atmosphere, and some lead will accumulate in solid residues (bottom ash and fly ash).
Taking Huainan mining area in Anhui as an example, the environmental geochemistry of lead in the process of coal mining is discussed. On the basis of the analysis of the content distribution in the epigenetic environment of the Pb mining area, the environmental hazards of Pb are evaluated and analyzed. The average lead content in the soil of the coal mine area is 28.3mg/kg, which is equal to the lead content in the coal gangue (29.2mg/kg); the coal gangue can be used. In the soil environment, the content of Pb in the soil collected in the mining area is higher, but the content of the subsidence lake water in the mining area is low, which indicates that the lead is migrated through the soil to the earthworm, and the water body is less affected by it.
The content of Pb in the crops of the mining area showed that the content of wheat roots was higher than that in the stems, leaves and shells, enriched in the grain, and exceeded the national limit on the content of lead in food (GB2762-2012). In the rice and soybean, most of the lead was fixed in the root, followed by the stem and shell. Among the three crops, the wheat had more lead to lead. In view of the level of lead content in Carassius carp meat within the limits of pollutants, the Carassius carassius cultivated in the collapsed lake water is considered to be suitable for food. By the calculation of daily intake and total harm, it is proved that the agricultural products produced in the mining area of the mining area are temporarily without greater risk.

【学位授予单位】：中国科学技术大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：X752;X142

【参考文献】