准格尔矿区主采煤层中铅和硒的异常高值与成因研究

Analysis of Anomalous High Concentration of Lead and Selenium and Their origin in the Main Minable Coal Seam in the Junger Coalfield

为了研究内蒙古准格尔主采煤层中铅和硒的异常,运用电离耦合等离子体质谱(ICP-MS)、仪器中子活化分析(INAA)、带能谱仪的扫描电镜(SEM-EDX)和光学显微镜对主采煤层中铅和硒的含量、赋存状态和地质成因进行了研究.实验结果表明,准格尔矿区主采6号煤层中铅和硒的质量分数均值分别为35.7×10-6和8.2×10-6,明显高于华北煤、贵州煤、中国煤和美国煤的算术均值,其富集系数分别高达2.4和68.1,铅和硒在该煤层中显著富集;铅和硒主要赋存在方铅矿、硒铅矿和硒方铅矿中,这3种矿物以植物胞腔充填形式出现,属于化学沉积成因.

The concentration, occurrence, and geological origin of lead and selenium in the main minable coal seam from the Junger coalfield were studied using inductively coupled plasma mass spectrometry （ICP-MS）, instrumental neutron activation analysis （INAA）, scanning electron microscope equipped with an energy-dispersive X-ray spectrometer （SEM-EDX）, and optical microscope. The results show that the average concentrations of Pb and Se are as high as 35.7μg/g and 8.2 μg/g, respectively, which are much higher than those of coals from North China, Guizhou, China, and USA. In addition, their enrichment factors are up to 2.4 and 68. 1, respectively. Lead and selenium are significantly enriched in the seam. Lead and selenium mainly exist in galena, clausthalite, and selenio-galena which occur as cell-filling of coal-forming plants and are of chemical-sedimentary origin.