沁水盆地晚古生代煤中硫的地球化学特征及其对有害微量元素富集的影响

煤中硫是多种有害微量元素的重要载体。基于形态硫分析、电感耦合等离子质谱及X射线衍射等方法分析沁水盆地晚古生代煤中硫和有害微量元素的分布规律，探讨了煤中硫对有害微量元素富集的影响，运用带能谱的扫描电镜和光学显微镜划分煤中硫化物的微观赋存特征。结果表明，沁水盆地煤中硫整体上以有机硫为主，平均占全硫的78%，只有在太原组个别高硫煤中以黄铁矿硫为占优势。显微镜和扫描电镜下可识别出煤中黄铁矿的微观赋存状态包括莓球状、薄膜状、晶粒状、结核状、团窝状黄铁矿和细粒黄铁矿集合体，白铁矿的微观赋存特征包括聚片状、板状和矛头状白铁矿，部分白铁矿与黄铁矿共生。沁水盆地煤中有害微量元素含量整体较低，黄铁矿是有害微量元素As、Se和Hg的重要载体，而有机硫决定了煤中U的富集。研究认为，成煤时期海水对泥炭沼泽的影响导致太原组煤中全硫和黄铁矿硫较高，太原组煤中硫的来源具有多样性，煤中黄铁矿具有多阶段演化的特点。

Geochemistry characteristics of sulfur and its effect on hazardous elements in the Late Paleozoic coal from the Qinshui Basin

Sulfur in coal is the main carrier of many hazardous trace elements. Based on sulfur form analysis, inductively coupled plasma mass spectrometry and X ray diffraction, the distribution of sulfur and hazardous trace elements in coal from the Qinshui Basin were analyzed and the influence of sulfur on hazardous trace elements was discussed. The occurrence modes of sulfide in coal were identified under microscope and scanning electron microscope with X ray energy dispersive spectrometer (EDX). The results show that organic sulfur is the main type of sulfur in coal, accounting for 78% of total sulfur. Pyritic sulfur only dominates in some high sulfur coals of the Taiyuan Formation. The microscopic occurrence modes of pyrite mainly include framboidal pyrite, thin layer pyrite, euhedral crystals, nodular pyrite, massive pyrite and fine grained pyrite accumulations, and the occurrence modes of marcasite mainly include polysynthetic marcasite, plate marcasite and spearhead marcasite, some of which co exist with pyrite. Hazardous trace elements in coal from the Qinshui Basin are low and will not affect the environment during coal mining and coalbed methane development. Pyrite is the main carrier of As, Se and Hg, while organic sulfur determines the content of U in coal. It is suggested that the influence of seawater during and after peat swamp stage is the key reason for high total sulfur and pyritic sulfur in coal of the Taiyuan Formation. Sulfur in coal of the Taiyuan Formation has diverse sources and pyrite in coal of the Taiyuan Formation is characterized by multi stage evolution.