Relationship between Thermal Metamorphism of Coal and the Periodic Variation Law of Geochemical Behavior of Elements:A Study on the C2 Coal Seam in the Fengfeng Mining Area of the Handan Coalfield in Hebei,China

This study highlights the response of the periodic variation of the geochemical behavior of elements to the thermal metamorphism of coal by considering the differentiation mode and differentiation degree of elements of the C2 coal seam in the Fengfeng mining area of the Handan Coalfield in Hebei,China.The periodic variation of the geochemical behavior of elements was observed to change towards a certain direction as the degree of metamorphism of a geological body increased.Based on the coincidence degree(or similarity degree)between the geochemical behavior of elements and periodic variation of elements,the 57 elements in this study were divided into two levels.The periodic variation of the geochemical behavior of first-level elements was largely synchronous with that of their first ionization energy,suggesting that only one differentiation mode exists and the elements are mainly inorganically associated.The differentiation mode of the second-level elements deviated to a certain extent from their first ionization energy;the larger the deviation,the more complicated and diverse was the differentiation mode.Among the second-level elements,the grade of coal metamorphism has evident and intuitive effects on the proportion of elements with particular structural features,such as the 4q+3 type of elements and the odd-odd elements.In addition,the distribution of elements in organic and inorganic matter within coal are subject to the structural features of the elements.The differentiation mode and differentiation intensity of elements could be characterized by the hierarchical parameter and differentiation intensity.The hierarchical parameter and differentiation intensity of certain elements showed a good positive or negative correlation with R_(max) in coal.The 57 elements in this study were quantitatively ordered according to the degree of magmatic hydrothermal fluid influence and thermal metamorphism of coal through graphs depicting the goodness of fit,correlation coefficient with R_(max),and differentiation intensity.The results of this study are consistent with the results of previous field research,illustrating the scientific significance and application value of this study on the periodic variation of the geochemical behavior of elements.

河北峰峰矿区煤中微量有害元素的赋存与分布

运用仪器中子活化分析、电离耦合等离子体原子发射光谱、带能谱仪的高分辨率扫描电镜以及逐级化学提取对河北峰峰矿区不同煤阶的煤中微量有害元素进行了测定,发现该矿区煤中微量有害元素含量均值与华北地台晚古生代煤的均值相比,As(3.21μg/g),Br(13.01μg/g),Co(6.21μg/g),Cu(31.29μg/g),Mo(3.63μg/g),Rb(7.73μg/g),Sn(9.60μg/g),W(1.62μg/g)等元素的含量偏高;该矿区不同变质程度煤中微量有害元素的含量不同,在明显受岩浆热液影响的无烟煤中As,Co,Cu,F,Fe,Mo,Ni,U,Zn含量较高;岩浆热液形成的方解石和黄铁矿脉是峰峰矿区无烟煤中Zn,As,Mo,Cu,Ni,Co等微量有害元素富集的主要载体。燃煤产物特别是飞灰中As(9.10μg/g),Co(10.55μg/g),Cr(58.18μg/g),Mo(13.95μg/g),Se(4.25μg/g),Th(34.50μg/g),U(7.65μg/g)的含量和原煤相比普遍较高,对它们的赋存状态及其对环境和人体健康的危害值得深入研究。

梅田矿区岩浆热变煤中微量元素分布特征

梅田矿区主采煤层———龙谭组１２ 号煤层主要是受矿区北部骑田岭花岗岩侵入体影响的典型岩浆热液变质无烟煤，煤的变质指标如挥发分（Ｖｄａｆ）和镜质组反射率Ｒｏ（ｍａｘ）等与岩体有密切关系。本次研究按距离岩体由近而远采集了一系列煤样，运用中子活化（ＩＮＡＡ）和微区分析等测试手段研究了样品中近４０ 种微量元素的分布特征，结果表明：（１）Ａｓ、Ｃｄ 、Ｈｇ 、Ｐｂ、Ｓｅ 等对人体有毒元素在煤中的质量分数较地壳克拉克值高数倍至数十倍，灰基质量分数则高数十至数百倍；（２） 绝大多数元素的灰基质量分数较植物灰和粘土＋ 板岩样中的质量分数高；（３）Ｃｅ、Ｃｒ、Ｅｕ、Ｈｆ、Ｋ、Ｌａ、Ｌｕ 、Ｎａ、Ｎｄ 、Ｎｉ、Ｒｂ 、Ｓｃ、Ｔｈ 、Ｕ、Ｗ、Ｙｂ 等元素的质量分数随离岩体距离的增大而有逐渐降低的趋势，而Ｃｄ、Ｃｕ 、Ｈｇ、Ｐｂ、Ｓｂ、Ｓｅ 等元素则逐渐增高。微量元素的这种分布特征与岩浆热液作用的阶段性有密切关系。

660MW燃煤锅炉细微颗粒物中次量与痕量元素的分布特性

应用承重撞击器(DGI)采样系统在南昌某电厂2#锅炉电除尘器前进行颗粒物采集,并同时采集了原煤样和底灰样。对飞灰的质量粒径分布、底灰和飞灰中次量与痕量元素的分布特性进行了分析。结果表明PM1.0和PM2.5质量分别占PM10质量的16.0%～17.4%和46.9%～50.6%;Na、Mg、P、S主要富集在亚微米颗粒物中,Al、Si、Ca、Ti、Fe、K主要富集在超微米颗粒物中;随着颗粒物粒径的减小,As、Cd、Cr、Pb的浓度逐渐增大,且在亚微米颗粒物中的增幅大于超微米颗粒物,Mn在各级颗粒物中浓度相近;As、Cd、Cr、Pb大量富集于亚微米颗粒物之上,Mn在各级颗粒物中富集特性无明显差异,且各痕量元素挥发特性存在以下规律:As>Cd>Cr>Pb>Mn;文中给出了无控制条件下痕量元素的排放因子,PM1.0中各元素排放比例存在以下规律:As>Cd>Cr>Pb>Mn。

煤中有害物质及其对环境的影响研究进展

综述了煤中有害物质的种类、分布赋存特征及对环境的影响研究进展。探讨了煤中黄铁矿的形态、世代交替、有机硫的结构及煤中硫的地质成因。阐述了煤中微量元素的种类、地质分布、赋存状态、迁移聚集机制及其环境危害。并对煤及燃煤产物中多环芳烃的种类、赋存规律及对环境和人类健康的危害进行了详细阐述。最后指出了煤中有害物质研究中存在的问题与发展趋势。

燃煤电厂煤粉炉及CFB锅炉PM_(2.5)产生及排放特性的现场实验研究

采用稀释采样方法对一台220 MW煤粉炉(锅炉A)及一台300 MW的CFB锅炉(锅炉B)电袋复合式除尘器前后PM2.5进行现场采样。通过ELPI测定PM2.5的粒径分布;采用SEM分析PM2.5的显微结构;采用EDX及ICP-OES分别对分级PM2.5中次量及痕量元素含量进行了检测。结果表明,锅炉A和B除尘前后对应的PM2.5粒数及质量浓度分布均不同;锅炉A和B产生的PM2.5分别以较为光滑球形和不规则形状为主,锅炉A除尘后PM2.5呈表面粗糙球形,锅炉B除尘后PM2.5单颗粒形貌特征不变;锅炉A和锅炉B产生的PM2.5除尘前后在各粒径段中Si、Al、Fe、Ca和Mg含量基本一致,As、Cd和Se含量随着粒径的减小而增大;除尘后锅炉A产生PM2.5中As和Se含量增加,且在亚微米PM2.5中As和Se含量的增加更明显,锅炉B除尘后PM2.5中As和Se含量基本不变。