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淮北煤田煤中汞的赋存状态 总被引：6，自引：0，他引：6
系统采集淮北煤田10、7、5、4和3煤层的29个煤样品, 采用逐级化学提取方法研究了煤中汞的赋存状态, 根据提取步骤和汞的特性, 将煤中的汞分为水溶态、离子交换态、有机态、碳酸盐结合态、硅酸盐结合态和硫化物结合态, 利用Flow Injection Mercury System(FIMS)分析了样品中总汞和不同形态中汞的含量.测试结果表明, 与华北石炭-二叠纪煤、中国煤以及美国煤含量相比较, 淮北煤田煤中汞的含量明显富集.逐级化学提取实验结果和煤中汞与硫、灰分的相关分析结果表明, 岩浆的侵入对煤中汞的赋存状态有较大的影响, 不受岩浆侵入影响的10、4和3煤层煤中的汞主要以有机态和硫化物结合态存在, 受岩浆侵入影响的5和7煤层中的汞主要以硅酸盐结合态存在. 相似文献
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煤中微量元素赋存状态的逐提试验研究 总被引：12，自引：0，他引：12
首次通过逐级化学提取试验对高级煤中10余个微量元素的赋存状态（水溶态及可交换态，碳酸盐铁锰氧化物结合态，有机质结合态，进入晶格或呈单矿物态）进行研究，结果表明：绝大多数元素具有一种以上的赋存状态；不同沉积环境条件下，元素的赋存态可以发生改变；元素的赋存状态不同，其入侵环境及对环境的危害程度不同。 相似文献
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对煤矸石中汞、砷的赋存形态进行研究,可以为煤矸石发电过程中汞、砷的脱除提供理论依据。采用逐级化学浸提法将3个不同产地煤矸石中汞、砷的赋存形态分为可交换态、碳酸盐结合态、铁锰结合态、硫化物结合态、有机结合态和残渣态。采用不同的浸提溶液得到对应结合态的测试结果。结果表明,煤矸石中汞、砷的赋存形态具有一定的相似性。煤矸石中汞、砷主要以硫化物结合态为主,其质量分数占总汞的67.66%~72.68%,占总砷的56.71%~79.36%;其次为残渣态,其质量分数占总汞的23.70%~28.06%,占总砷的11.47%~18.02%。另外在煤矸石中砷还以少量有机结合态形式存在。 相似文献
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本文以重庆巫山地区上二叠统黑色岩系为研究对象,通过全岩化学分析、矿物分析、连续化学提取、浸提实验等方法,揭示黑色岩系中有害微量元素的赋存状态及其环境意义.结果表明,研究区黑色岩系样品富含有机碳和硫,为典型缺氧条件下的产物;明显富集Cd、Cr等有害元素.Cd主要赋存于碳酸盐矿物中,Cr主要赋存于硅酸盐矿物,Zn和Ni的赋存载体包括硫化物、有机质等.不同样品中有害元素的赋存状态有所差异,且与矿物组分密切相关.母岩中有害元素赋存状态的差异可能控制其在土壤等环境介质中的活性;硫化物含量高而碳酸盐矿物含量低的黑色岩系样品,有害元素释放量大,潜在生态风险高,应引起高度重视. 相似文献
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西南寒武、二叠系富硒碳质岩中硒结合态的比较研究 总被引：6，自引：0，他引：6
使用硒的7步连续化学提取技术,对采自贵州寒武纪牛蹄塘组和湖北恩施二叠纪茅口组富硒碳质岩中的水溶态、可交换态、有机态、元素态、酸性提取态、硫化物/硒化物态和残渣态硒进行了比较研究,应用氢化物－原子荧光法测定了岩石总硒和各结合态硒。结果表明,恩施二叠纪沙地新鲜富硒碳质硅质岩和碳质页岩中的硒主要以有机结合态和硫化物/硒化物态硒为主,残渣态硒较低;遵义松林早寒武世碳质硅质岩中的硒主要以有机结合态和硫化物态硒为主,碳质页岩与镍钼矿层中则以有机结合态、残渣态和硫化物态硒为主,斑脱岩中主要以有机结合态、元素态和可交换态硒为主。根据硒结合态的这种分布特征,推测二叠纪、寒武纪富硒碳质岩中硒初始富集的生物地球化学过程略有差异：前者碳质硅质岩中主要以微生物还原为主,碳质页岩中则是微生物还原作用和生物同化吸收或吸附兼而有之;后者主要以生物同化吸收或吸附为主,微生物还原次之。 相似文献
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中国煤中砷的含量分布、赋存状态、富集及环境意义 总被引：14，自引：1，他引：14
砷是煤中有害微量元素之一,在煤加工利用过程中,砷会以各种形式释放出来,进入环境。本文在全面分析现有资料和文献的基础上,结合作者对中国煤中砷的研究成果,分析了中国煤中砷的含量与分布、赋存状态、富集因素以及环境意义。通过研究和分析可知,中国煤中砷的平均值约为5μg/g,但在不同地区、不同时代以及不同类型的煤中有较大的差异,除中国西南地区含量异常高外,一般含量均在10μg/g以内;煤中砷的赋存状态多种多样,主要以无机态的硫化物结合为主,并常与黄铁矿等矿物伴生,也存在有机态结合的砷;中国煤中砷的来源和富集主要是以陆源母岩、成煤植物、沉积环境和构造裂隙—热液作用等为主的多种因素综合控制的结果;在煤燃烧过程中,煤中的砷释放出来,并对长期生活在燃煤地区的环境和人体产生影响。本文还提出今后煤中砷研究的主要方向,以为煤中砷的研究提供参考资料。 相似文献
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恩施渔塘坝富硒碳质岩石中硒的形态分析 总被引：2，自引：0，他引：2
湖北恩施渔塘坝是中国人群硒中毒爆发性流行的地区，也是恩施较为典型的高硒地区之一。其北部出露的富硒碳质岩石，通常认为是渔塘坝硒的主要来源。采用7步连续化学浸提技术，将富硒碳质岩石中硒分为水溶态、可交换态、有机态、元素态、酸性提取态、硫化物／硒化物态和残渣态硒，使用氢化物-原子荧光法测定了岩石总硒和硒形态。结果表明，碳质页岩和碳质硅质岩中硒主要以有机态、硫化物／硒化物态和可交换态硒为主，碳质泥岩中硒以有机态、元素态和硫化物／硒化物态硒为主。碳质泥岩中的水溶态硒显著低于碳质页岩和碳质硅质岩中的水溶态硒，但元素态硒的比例显著高于后两者，说明碳质泥岩是富硒碳质岩层中硒易于富集的场所。富硒碳质岩中的可利用态硒主要以Se^4＋为主，而非是Se^6＋和有机硒。可交换态和有机结合态硒中Se^4＋与岩石总硒的显著正相关关系表明，Se^4＋离子的分布影响着岩石总硒，有机质与粘土在硒富集的地球化学过程中承担了重要作用。 相似文献
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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 总被引：1，自引：0，他引：1
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。 相似文献
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贵州普安矿区晚二叠世煤中贵金属元素的赋存状态和地质成因 总被引：4，自引：0，他引：4
运用电感耦合等离子体质谱(ICP-MS)和逐级化学提取技术(SCET)对贵州西部普安矿区晚二叠世煤中贵金属元素的含量、赋存状态和成因机理进行了研究.结果表明,贵州普安矿区2号主采煤层的矿物组成主要为低温热液流体成因的黄铁矿和陆源碎屑成因的粘土矿物;与中国煤煤相比,该煤中Rh(38 ng/g)、Pb(640 ng/g)、Ir(9 ng/g)、Pt(98 ng/g)、Au(16 ng/g)和Ag(1620 ng/g)明显富集,其中Pb、Ir、Au的含量分别是中国煤的4.3倍、9倍和5.3倍.逐级化学提取结果表 相似文献
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The aim of this study was to investigate the geochemical characteristics of arsenic in the solid material samples of the Mae Moh Mine and also the Mae Moh power plants fly ash samples were systematically studied. Arsenic concentration in overburden, coal lignite and fly ash are variable (depending on source of solid samples). The results show that the strata of overburden, J seam of coal and fly ash are rich in arsenic and also relatively soluble from fly ash; it occurs as a surface precipitate on the ash particle. The experimental study on speciation in the strata also indicates that the arsenic speciation of Mae Moh solid samples are mainly arsenate, As (V), which are approaching exceed 80%. Arsenic content in the main of overburden is in the range of 14.3–888.8 mg/kg, which is larger than the arsenic background soil values. Solid materials polluted wastewater; the arsenic speciation was present predominantly as arsenate in the surface water of a series of Mae Moh solid materials basins. 相似文献
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西藏搭格架高温热泉是我国大陆少有的大型间歇性喷泉,砷元素作为对人类威胁极大的环境问题普遍存在于热泉之中,搭格架高温热泉中砷元素质量浓度最高已达到了9.75 mg/L,其对地表水和浅层地下水的污染不容忽视。硫代砷是富含硫化物热泉中砷的存在形态之一,鉴于国内相关研究较少,本文对西藏搭格架地热区的热泉样品进行了水化学分析,并利用水文地球化学模拟软件PHREEQC开展了对热泉中砷元素存在形态的地球化学模拟。结果表明：西藏搭格架热泉中砷元素的存在形态有亚砷酸盐、砷酸盐和硫代砷,其中亚砷酸盐与砷酸盐是砷的主要存在形态,且在pH影响下两者之间存在相互转化关系;各种硫代砷按质量浓度由高至低依次为一硫代砷酸盐、三硫代砷酸盐、二硫代砷酸盐、一硫代亚砷酸盐、四硫代砷酸盐;硫代砷形态占总砷浓度比例主要受热泉中硫化物质量浓度、Eh（氧化还原电位）和pH等因素的控制,在硫化物质量浓度总体偏低的情况下,硫化物质量浓度的上升可促进其他形态的砷向硫代砷形态转化,强还原性环境有利于硫代砷形态的存在;此外,在中性环境下,硫代砷占总砷浓度比例随pH上升亦有上升趋势。 相似文献
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金川镍矿浮选尾矿数量巨大,含有相当可观的有价金属,其中有价金属的回收受到越来越多的关注。金川老尾矿库尾矿砂中Ni和Cu赋存状态复杂,水溶性矿物态、可交换离子态、碳酸盐态、结晶度较差的Fe氧化物态、结晶度较好的Fe氧化物态、硫化物态和残渣态中都含有数量不等的有价金属Ni和Cu;尾矿砂风化作用释放的金属阳离子大多数在发生氧化的硫化物位置原位发生水解沉淀形成次生矿物,有价金属Ni和Cu在尾矿库中没有发生明显的富集。金川镍矿尾矿砂中Ni和Cu适于用化学酸溶浸出的方法进行二次回收。 相似文献
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《International Journal of Coal Geology》2005,61(3-4):141-196
The review presented covers: (a) historical introduction; (b) some analytical comments; (c) some peculiarities of the As geochemistry in environment; (d) an estimation of coal Clarke value of As; (e) some coals enriched in As; (f) mode of As occurrence in coal; (g) factors influencing the As distribution in coal matter and coal bed; (h) genetic topics; (i) some topics related to environmental impact of As by the coal combustion.The World average As content in coals (coal Clarke of As) for the bituminous coals and lignites are, respectively, 9.0±0.8 and 7.4±1.4 ppm. On an ash basis, these contents are higher: 50±5 and 49±8 ppm, respectively. Therefore, As is a very coalphile element: it has strong affinity to coal matter — organic and (or) inorganic but obligatory authigenic. The coalphile affinity of As is like that for Ge or S.There is strong regional variability of As distribution due to geologic variability of the individual coal basins. For example, bituminous coals in Eastern Germany, Czech Republic and SE China are enriched in As, whereas the coals in South Africa or Australia are very depleted compared to coal Clarke of As. In general, some relationship exists between As content and its mode of occurrence in coals. Typically, at high As content, sulphide sites dominate (pyrite and other more rare sulphides), whereas at low As content, Asorg dominates, both being authigenic. A contribution of the terrigenic As (in silicates) is usually minor and of the biogenic Asbio (derived from coal-forming plants) is poorly known.Both organic and inorganic As can exist not only as chemically bound form but also in the sorbed (acid leacheable) arsenate form. With increasing coal rank, sorbed exchangeable arsenate content decreases, with a minimum in the coking coals (German data: the Ruhr coals).Relations of As content in coal to ash yield (or its partitioning in sink–float fractions) and to coal petrographic composition are usually complicated. In most cases, these relations are controlled by main site (form) of As — Aspyr or Asorg. If Aspyr dominates, an As accumulation in heavy fractions (or in high-ash coals) is observed, and if Asorg dominates, it is enriched in medium-density fractions (or low- and medium-ash coals). Arsenic is in part accumulated in the inertinite vs. vitrinite (Asorg ?).There are four genetic types of As accumulation on coal: two epigenetic and two syngenetic: (1) Chinese type—hydrothermal As enrichment, sometimes similar to known Carlin type of As-bearing telethermal gold deposits; (2) Dakota type—hypergene enrichment from ground waters draining As-bearing tufa host rocks; (3) Bulgarian type—As enrichment resulting from As-bearing waters entered coal-forming peat bogs from sulphide deposit aureoles; (4) Turkish type—volcanic input of As in coal-forming peat bog as exhalations, brines and volcanic ash.During coal combustion at power plants, most of the initial As in coal volatilizes into the gaseous phase. At the widely used combustion of pulverized coal, most of Asorg, Aspyr and “shielded” As-bearing micromineral phases escape into gaseous and particulate phase and only minor part of Asclay remains in bottom ash. The dominant fraction of escaping As is in fly ash. Because 97–99% of the fly ash is collected by electrostatic precipitators, the atmospheric emission of As (solid phase and gaseous) is usually assumed as rather minor (10–30% from initial As in coal). However, fly ash disposal creates some difficult environmental problems because it is potentially toxic in natural waters and soils. The As leaching rate from ash disposal is greatly controlled by the ash chemistry. In natural environment, As can be readily leached from acid (SiO2-rich) bituminous coal ashes but can be very difficult from alkali (CaO-rich) lignite ashes.If the Aspyr form dominates, conventional coal cleaning may be an efficient tool for the removing As from coal. However, organic-bound or micromineral arsenic (“shielded” grains of As-bearing sulphides) are not removed by this procedure.Some considerations show that “toxicity threshold” of As content in coal (permissible concentration for industrial utility) may be in the range 100–300 ppm As. However, for different coals (with different proportions of As-forms), and for different combustion procedures, this “threshold” varies. 相似文献
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A sequential extraction procedure, using acid digestion in a CEM MDS-81D® microwave system, is reported for the investigation of trace and minor element associations in coal in (1) mineral phases other than pyrite, (2) pyrite and (3) the organic matrix. The concentrations of sulphate, pyrite and organic sulphur can also be determined by this method. The extract solutions from each stage are rapidly analysed by ICP-AES. The association of major, minor and trace elements with mineral and organic phases is suggested for a suite of certified reference coal samples. In stage 1, a significant percentage of the total Ba, Co, Cr, Cu, Mn, Ni, Pb and Sr was extracted suggesting an association with silicate, carbonate, sulphate and phosphate minerals for these elements. In stage 2, a proportion of the Cu, Mn, Ni, Pb and Zn was dissolved implying the occurrence of these elements in pyrite. An association with the organic matrix is suggested for Cr and also for Ba and Sr in lower rank coals. 相似文献
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对拜仁达坝铅锌矿矿集区3个多金属矿区的3个土壤粒级样品中Zn、Pb、Cu、Ag 4种主要成矿元素的7种赋存形式(水溶态、离子交换态、碳酸盐结合态、有机质结合态、铁锰氧化物结合态、硫化物结合态和残渣态)进行了测定。研究结果表明:1银都矿区土壤中Zn、Pb和Ag浓度最高,而道伦达坝矿区土壤中Cu的浓度最高;2拜仁达坝矿集区土壤中Zn、Pb和Cu主要以残渣态形式赋存,而Ag主要以铁锰氧化物结合态和硫化物结合态形式赋存;3拜仁达坝矿集区Zn、Pb和Cu元素在3个土壤粒级中的各个赋存形式所占的比例略有差别,但总体上大致相同,而Ag元素的赋存状态在3个土壤粒级的差异较大;4 3个矿区土壤中水溶态、离子交换态、碳酸盐结合态和有机质结合态的Zn和Pb差别不大;铁锰氧化物结合态、硫化物结合态和残渣态的Zn和Pb,以及Cu和Ag的7个赋存状态在3个矿区的差别较大。 相似文献
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黔西南高砷煤的分布及地球化学特征研究 总被引：23，自引：3，他引：20
根据野外地质特征结合中子活化成分分析结果,探讨了黔西南高砷煤的分布特征、影响因素和某些地球化学特征。高砷煤严格受构造（褶皱和断层）、地层（二叠系龙潭组）、沉积相（海陆交互相）的控制,分布于平行北斜长轴的断层两侧,愈靠近断层面砷的含量愈高。砷在煤中的分布极不均匀,即使同一煤层变化也极大。在时空关系与元素组合上高砷煤与区内卡林型金矿密切相关。 相似文献