本文简要综述了煤中汞的分布规律、赋存状态、成因及燃烧过程中迁移转化和对环境的影响。

obtained by ashing of the coal under 850℃. Comparative-leaching experiments were carried out on each fraction under various pH conditions. A mathematical model for leaching of trace elements has been developed and leaching intensity (I1) has been calculated for each element. The results show that pH of the solution, leaching time, and particularly, properties and occurrence of the elements, have a strong influence on leaching behavior.

研究了山西神头电厂炉前煤(C)、炉前煤实验室高温灰化灰(HA)、飞灰(FA)和底灰(BA)中砷的分布, 用用X射线衍射以及光学显微镜分析和观察了样品中矿物组成, 并用逐级化学提取方法研究了砷在它们中的赋存状态. 研究表明, FA中砷含量最高,BA的砷含量最低; 燃煤产物中50%以上的砷进入玻璃质硅酸盐相或莫来石矿物晶格, 20%～30%与碳酸盐和铁锰氧化物结合,15%～20%的砷呈水溶态和可交换态; 因为水溶态和可交换态的砷容易进入水环境中, 所以, 对电厂燃煤产物中砷对水环境的潜在危害应予以重视.

In this paper, geochemical characteristics of rare earth elements (REE) in acid mine drainage (AMD) from the Sitai coal mine of Shanxi Province, North China were investigated by determining concentrations of dissolved REEs and major solutes in the AMD samples, concentrations of REEs in the AMD precipitate samples and country rock samples (mudstone and coal), and modeling REEs species in the AMD. The results show that AMD in the Sitai coal mine have high REEs and SO42− concentrations in comparison with several terrestrial waters worldwide. The REE speciation modeling indicates that sulfate complexes (LnSO4+, >60%) and free metal species (Ln3+, 20%–40%) are dominant REEs species in the AMD. AMD of the Sitai coal mine also shows a middle REE-enriched NASC (North American Shale Composite)-normalized pattern. The authors suggest that both REE sulfates (LnSO4+) in the AMD and country rock of coal measures are possible reasons for middle REE-enriched NASC-normalized pattern of the Sitai coal mine AMD. Further work on the AMD precipitates is needed to obtain more information on the origin of the middle REE-enriched NASC-normalized patterns.

The concentrations of forty-five elements in 137 Chinese coals collected from the main coal fields and representing the main coal-forming periods were determined using instrumental neutron activation analysis (INAA), atomic absorption spectrometry(AAS), inductively coupled plasma atomic emission spectrometry(ICP-AES), and atomic fluorescence spectrometry(AFS). Among the elements determined are the following minor and trace elements which are important to environmental protection and human health: As, Cd, Pb, Hg, Se, Mn, Ni, Cu, Zn, Sb, Co, Mo, F, Cl, V, Ba, U and Th. The ranges and means of concentrations of these elements are given. Comparison with world averages and geometric means of concentrations in American coals shows that the concentrations of most elements are higher in Chinese coals. However, it is necessary to point out that although the samples are representative, the number of samples is small. Hence, these are only preliminary results. Finally, five major genetic types of enrichments of minor and trace elements in Chinese coals are proposed on the basis of Chinese coal geology, namely, source-rock-controlled type; sedimentation-controlled type; magmaticrhydrothermal-controlled type; fault-controlled type; and groundwater-controlled type.

测定贵州兴仁、兴义晚二叠世6个高砷无烟煤样品中As含量为94.1μg·g-1～3.2%,Sb含量为8.1～120μg·g-1.对样品的矿物学研究表明，未发现任何含As或As的独立矿物，As是赋存在煤有机组分中，应用同步辐射X射线吸收精细结构仪测定样品中As的结构发现，赋存在高砷煤有机组分中的As与O配位，除在1个样品中As与3个O配位外，在其余样品中As均与4个O配位。因此，高砷煤中的As不是赋存在硫化物矿物中，而是赋存在砷酸盐或亚砷酸盐相中，且主要是砷酸盐相。

本文给出了煤中有害微量元素的定义，即煤中含量小于1.0%的有毒元素、致癌元素、腐蚀性元素、放射性元素以及其它对环境有害的元素等。根据我国环保要求，提出当前应重视的有害元素，共22种。作者还讨论了煤中有害微量元素对环境的危害以及国内外对煤中微量元素的研究现状和存在的问题。

Concentrations of rare earth elements (REE) in Jurassic coal of YanAn Formation from Dongsheng coalfield located in the northeast of Ordos basin were determined by instrumental neutron activation analysis (INAA). Curves of distribution pattern of REE were drawn, and many geochemical parameters were calculated. The result shows that 1) The contents of REE in Jurassic coal with low ash and sulfur are lower than those of Carboniferous and Permian coal from the Basin of North China ; 2) Inside the Dongsheng coalfield, coal from the north has higher contents of REE than that form the south because the north is near the area of source rock which is the main supplier of REE, while the south is far away from the area of source rocks ; 3) Although Jurassic coal in Dongsheng is the low-ash coal with less than 10 %, the contents of REE are stillproportional to ash yield of ash and SiO2 contents. 4) Although the J urassic coal in Dongsheng were deposited in oxidative continental environment of river-lake, Eu depletion of REE in coal commonly exists, and positive abnormity of Ce dose not exist. This reflects the REE distribution pattern of REE in source rock of continental area ; and 5) Compared with other rocks, coal shows extremely complexity of distribution pattern of REE, which is the result of continuous alteration and redistribution of matter in coal occurred in open basin system.

以水化学数据为依据,应用相关分析,结合地质、水文勘探资料,对煤矿酸性矿排水(AMD)的水化学特点及其成因进行了研究。煤矿AMD在一定的物质条件和环境条件下形成,只要条件适宜,不管是高硫煤还是低硫煤均可产生酸性水;低pH、高Eh、高TDS及高硬度是煤矿AMD的重要特征,水中的SO42-与其EC之间以及Fe3+/Fe2+比值与其Eh值走势具有良好的一致性,水中微量元素及重金属来源较复杂,如Ni、Cu、Co 、Zn等来源于黄铁矿的氧化溶解,但Pb、Sr等主要来自AMD对煤系地层中煤及岩石中矿物的淋滤作用。

砷是煤中常见的有害微量元素,由于其丰度较低,定量研究其赋存状态一直很困难。近年来,采用逐级化学提取实验方法对煤中不同赋存状态的砷进行了定量研究,综合分析这些研究可得出以下结论: ①煤中砷的赋存状态包括硫化物态砷、有机态砷、砷酸盐态砷、硅酸盐态砷、水溶态和可交换态砷。总体上,硫化物态砷> 有机态砷> 砷酸盐态砷> 硅酸盐态砷> 水溶态和可交换态砷,但在不同的煤样品中,也表现出较大的差异性。②一般而言,煤中大部分砷存在于含砷黄铁矿中,含砷黄铁矿中的砷含量与黄铁矿的成因或类型有关。煤中的砷酸盐态砷主要与铁氧化物和氢氧化物共生;硅酸盐态砷主要进入粘土矿物晶格。③在砷含量较低的煤样品中,有机态砷含量较高,其中在褐煤和低煤级烟煤中,可提取出与腐殖酸和富里酸结合的砷。当前还难以确认有机态砷的化学结构。④贵州特高砷煤中砷的赋存状态较为复杂,在某些样品中与氧结合的有机态砷为主要的赋存状态。