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1.
含砷尾矿中砷(As)及伴生元素铊(Tl)等毒性元素易向周边水和土壤介质中迁移,揭示尾矿中毒性元素的矿相特征及其释放机制具有重要意义。本研究以某雄黄矿区含砷尾矿为研究对象,结合化学分析、矿物学表征等手段,通过静态浸出实验探究含砷尾矿中As和Tl的矿相特征及其释放机制。研究结果表明,含砷尾矿中As和Tl的环境行为明显受到其矿相特征及赋存形态影响。矿物学分析结果显示尾矿中As的主要矿物相为砷铂矿和砷铁矿,矿物解离度表明砷矿物处于风化状态,As释放风险较高;而Tl则以伴生元素形式存在于Ca、Mn和Mg等矿物相中,这些矿物的沉淀溶解控制着尾矿中Tl的释放。尾矿中As主要以铁锰氧化物结合态和有机结合态存在,Tl主要以铁锰氧化物结合态和残渣态存在。酸性浸出条件下金属的活性态比例增高,可交换态As由0.29%上升至1.67%,可交换态Tl从5.46%升高至8.67%;尾矿中As释放加强而Tl受到抑制,表明尾矿中As与Tl释放存在竞争关系。As的浸出符合双常数模型,为多因素控制的物理和化学过程;Tl的浸出符合抛物线扩散模型,由结构掺入和表面吸附等扩散机制控制。本研究明确了含砷尾矿As和Tl的释放特性、化... 相似文献
2.
以氢气发生器为氩-氢火焰提供纯净、稳定的氢气,原子荧光光谱法测定土壤中水溶态和可交换态Sb(Ⅲ)和Sb(Ⅴ)已有应用,本研究进一步将此方法用于测定土壤样品中的As(Ⅲ)和As(Ⅴ)。在0.3mol/L NaH2PO4-Na2HPO4缓冲液中,采用氢化物发生-原子荧光光谱法测定土壤中水溶态As(Ⅲ)和总砷的含量,通过差减法计算As(Ⅴ)的含量。实验考察了0.02～0.4 mol/L NaH2PO4-Na2HPO4对As(Ⅲ)和As(Ⅴ)测定的影响,结果表明0.3 mol/L NaH2PO4-Na2HPO4可以有效掩蔽As(Ⅴ)。As(Ⅲ)的检出限为2.92 ng/g,总砷的检出限为2.35 ng/g;As(Ⅲ)和As(Ⅴ)的加标回收率分别为96%～104%和101%～103%。本方法不再依靠化学反应产生氢气来点燃并维持氩氢火焰,可在发生氢化反应的任何介质中测定砷,且不需要考虑酸度问题。方法操作简便,准确度高,能满足大批量样品分析要求。 相似文献
3.
贵州平坝白云岩风化壳稀土超常富集层中稀土赋存状态的研究 总被引：10，自引：1，他引：9
以平坝白云岩风化壳剖面为例,主要利用化学连续提取的方法,结合透射电镜的分析,对碳酸盐岩风化壳岩-土界面附近的稀土超常富集层中REE的赋存状态进行了研究,获得了REE在水溶态及可交换态(相态Ⅰ)、碳酸盐结合态及专性吸附态(相态Ⅱ)、非晶质氧化铁锰结合态(相态Ⅲ)、晶质氧化铁锰结合态(相态Ⅳ)、有机质及硫化物结合态(相态Ⅴ)和残渣态(相态Ⅵ)等6种相态的含量及变化规律.结果表明,REE在富集层中主要以专性吸附态、残渣态和有机态为主.风化前缘可溶态稀土所占比例较高,为稀土在风化壳中的迁移、转化提供可能;基岩中原生含磷稀土矿物的风化产生的稀土磷酸盐矿物的聚集导致了残渣态稀土大量存在于风化前缘;此外,由于风化淋溶的不断进行,可溶态的REE在高的pH值条件与剖面中的有机质、铁锰氧化物和粘土矿物共同作用下沉淀、富集,也导致了风化前缘稀土的超常富集. 相似文献
4.
土壤中不同形态砷的分析方法 总被引：5，自引：1，他引：4
选取磷酸作为提取剂,比较了超声和水浴两种方法辅助提取土壤中不同形态的砷,离子色谱一氢化物发生原子荧光光谱联用法(IC-HGAFS)测定砷的4种形态,即As(Ⅲ)、As(Ⅴ)、MMA (甲基胂酸)和DMA(二甲基胂酸)。从测定结果可以看出,水浴的提取效果明显高于超声的提取效果。土壤中砷以无机态为主,而无机态砷又以As(Ⅴ)为主,没有检测到有机砷。测定土壤中各种形态砷的加标回收率为72.0%～105.4%,相对标准偏差(RSD,n=5)为2.61%～8.19%。 相似文献
5.
《吉林大学学报(地球科学版)》2015,(Z1)
<正>水体中砷的迁移转化行为受其赋存形态影响。一般有氧水体和缺氧水体中,常见的无机砷形态为砷酸根(HAs O42-,H2As O4-和As O43-)或亚砷酸(H3As O3);在一些含硫的缺氧水体中,元素硫参与砷的地球化学循环,与之形成含砷硫化物沉淀或者可溶的硫代砷(thioarsenic species)。硫代砷形态十分复杂,按照砷的价态可分为硫代As(V)(thioarsenate,H3AsVOx S4-x,x=0~3)和硫代As(III)(thioarsenite,H3AsIIIOx S3-x,x 相似文献
6.
毒砂是常见的含砷硫化物矿物。在金属硫化物矿山环境中,含毒砂矿石和尾矿的风化会导致严重的重金属污染,在其风化过程中,微生物能够显著促进毒砂的氧化分解。本文实验研究了Acidithiobacillus ferrooxidans氧化分解毒砂矿物的现象,利用X射线衍射和扫描电子显微镜,分析了毒砂微生物氧化作用形成的次生矿物类型,发现毒砂表面存在As含量明显不同的2类次生产物,观察到黄钾铁矾、臭葱石、自然硫和施威特曼石等矿物;借助光电子能谱仪重点分析了微生物作用前后毒砂晶面的表面化学组成,基本查明了Fe、As和S三种元素的价态变化,初步探讨了毒砂表面次生矿物成因和As的化学态转化。 相似文献
7.
煤中砷的赋存状态 总被引：22，自引：0，他引：22
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。 相似文献
8.
砷是土壤中重要的(类)重金属污染物,其毒性主要取决于在环境中的形态及氧化还原状态。游离态Fe(Ⅱ)(Fe(Ⅱ)_(aq))驱动铁(氢)氧化物晶相重组过程是土壤铁循环的重要组成,对土壤中重金属的吸附、固定、钝化等环境行为有重要影响。本研究采用~(57)Fe稳定同位素示踪方法研究厌氧条件下Fe(Ⅱ)_(aq)驱动针铁矿晶相重组过程中砷的氧化还原及形态变化过程。结果显示,在只有针铁矿存在的对照处理中,针铁矿本身对As(Ⅲ)没有氧化作用,但83%的As(Ⅲ)被吸附到针铁矿表面。在Fe(Ⅱ)_(aq)和针铁矿共存体系中,Fe(Ⅱ)_(aq)可与针铁矿中结构态Fe(Ⅲ)发生铁原子交换,As(Ⅲ)的存在降低了铁原子交换速率。同时,在Fe(Ⅱ)_(aq)驱动针铁矿晶相转化过程中,77%的As(Ⅲ)被氧化成As(Ⅴ),As活性降低。另外,部分吸附在针铁矿表面的As(Ⅲ)和氧化转化后的As(Ⅴ)通过针铁矿的晶格单元包裹或取代Fe结构位的形式被针铁矿结构化固定,从而进一步降低了As的活性。 相似文献
9.
为探讨富硫化物尾矿酸化及重金属污染特征,选择安徽铜陵水木冲尾矿库浅层(0～90 cm)剖面为研究对象,对其结构特点、矿物组成、重金属(Pb、Cd、Zn、Ni、Cr、Mn、Cu和As)含量及赋存形态进行研究。结果表明,该尾矿库浅层出现分层现象,即表层为强硬化层,向下依次为弱硬化层和松散层,且呈酸性;矿物主要以辉石、长石、云母和石膏为主,由浅及深,金属硫化物及碳酸盐型矿物特征峰呈现增强的趋势;重金属呈现两种富集类型:表层(0～30cm,As、Pb)富集和中部(40～60 cm,Cd、Cu、Mn、Ni、Zn和Cr)富集型,其中Cu、Cd、As污染较为严重。由相关性分析可知,部分金属之间存在一定的伴生性,且p H值是影响重金属迁移的重要因素之一。该尾矿重金属主要以残渣态为主,其中Pb的潜在迁移能力最强,As最弱,顺序为Pb Cd Zn Ni Cr Mn Cu As。 相似文献
10.
江西冷水坑矿田下鲍Ag-Pb-Zn矿床地质特征及银的赋存状态研究 总被引：5，自引：2，他引：3
下鲍大型Ag-Pb-Zn矿床位于江西冷水坑矿田西南部。矿床地质研究表明,成矿作用可以分三个阶段:(Ⅰ)闪锌矿-黄铁矿阶段;(Ⅱ)方铅矿-闪锌矿-银矿物阶段;(Ⅲ)黄铁矿-石英(方解石)阶段。岩矿石光薄片鉴定和电子探针分析表明,下鲍矿床主要金属硫化物为闪锌矿、方铅矿、黄铁矿及银矿物。电子探针分析显示,银主要以独立银矿物形式存在,金属硫化物中不可见银极少。银矿物种类主要为螺状硫银矿和自然银,呈裂隙银赋存于铁锰碳酸盐中或呈粒间银分布于铁锰碳酸盐粒间和早期硫化物晶隙间;另有少量硫银锡矿、含银黝铜矿、淡红银矿、金银矿及深红银矿、硫砷铜银矿等银矿物,呈亚显微粒状赋存于铁锰碳酸盐粒间或呈固溶体分离结构赋存于方铅矿、闪锌矿等硫化物中。主要银矿物大量赋存于铁锰碳酸盐中,表明银矿化与铁锰碳酸盐可能存在成因联系。 相似文献
11.
E. M. Prasolov S. A. Sergeev B. V. Belyatsky E. S. Bogomolov K. A. Gruzdov I. N. Kapitonov R. Sh. Krymsky V. O. Khalenev 《Geochemistry International》2018,56(1):46-64
This paper reports the first results of a study of 11 isotope systems (3He/4He, 40Ar/36Ar, 34S/32S, 65Cu/63Cu, 62Ni/60Ni, 87Sr/86Sr, 143Nd/144Nd, 206–208Pb/204Pb, Hf–Nd, U–Pb, and Re–Os) in the rocks and ores of the Cu–Ni–PGE deposits of the Norilsk ore district. Almost all the results were obtained at the Center of Isotopic Research of the Karpinskii All-Russia Research Institute of Geology. The use of a number of independent genetic isotopic signatures and comprehensive isotopic knowledge provided a methodic basis for the interpretation of approximately 5000 isotopic analyses of various elements. The presence of materials from two sources, crust and mantle, was detected in the composition of the rocks and ores. The contribution of the crustal source is especially significant in the paleofluids (gas–liquid microinclusions) of the ore-forming medium. Crustal solutions were probably a transport medium during ore formation. Air argon is dominant in the ores, which indicates a connection between the paleofluids and the atmosphere. This suggests intense groundwater circulation during the crystallization of ore minerals. The age of the rocks and ores of the Norilsk deposits was determined. The stage of orebody formation is restricted to a narrow age interval of 250 ± 10 Ma. An isotopic criterion was proposed for the ore-bearing potential of mafic intrusions in the Norilsk–Taimyr region. It includes several interrelated isotopic ratios of various elements: He, Ar, S, and others. 相似文献
12.
奥地利安东帕有限公司 《岩矿测试》2009,28(3):306-306
最新的流行病学研究表明,空气中较高浓度的悬浮细颗粒可能对人类的健康有不利的影响。根据该项研究显示,由于心脏病、慢性呼吸问题和肺功能指标恶化而导致死亡率的升高与细尘粒子有关。这些研究结果已经促使欧盟于1999年4月出台了限制空气中二氧化硫、二氧化氮、氧化氮、铅和颗粒物含量的法案(1999/30/EC),对各项指标包括对可吸入PM10颗粒的浓度提出了新的限制性指标。PM10颗粒是指可以通过预分级器分离采集的气体动力学直径小于10μm的细颗粒。目前研究的兴趣重点逐步偏向PM2.5这些更细微颗粒物,PM2.5这种颗粒物对健康有明显的不利影响。在欧盟指令2008/50/EC中,对PM10和PM2.5都提 相似文献
13.
S. Viswanathan K. Surya Prakash Rao B. Mahabaleswar 《Journal of the Geological Society of India》2013,82(6):621-627
Komatiites are mantle-derived ultramafic volcanic rocks. Komatiites have been discovered in several States of India, notably in Karnataka. Studies on the distribution of trace-elements in the komatiites of India are very few. This paper proposes a simple, accurate, precise, rapid, and non-destructive wavelength-dispersive x-ray fluorescence (WDXRF) spectrometric technique for determining Sc, V, Cr, Co, Ni, Cu, Zn, Rb, Sr, Y, Zr, Nb, Ba, Pb, and Th in komatiites, and discusses the accuracy, precision, limits of detection, x-ray spectral-line interferences, inter-element effects, speed, advantages, and limitations of the technique. The accuracy of the technique is excellent (within 3%) for Sc, V, Cr, Co, Ni, Cu, Zn, Rb, Sr, Zr, Nb, Ba, Pb, and Th and very good (within 4%) for Y. The precision is also excellent (within 3%) for Sc, V, Cr, Co, Ni, Cu, Zn, Rb, Sr, Y, Zr, Nb, Ba, Pb, and Th. The limits of detection are: 1 ppm for Sc and V; 2 ppm for Cr, Co, and Ni; 3 ppm for Cu, Zn, Rb, and Sr; 4 ppm for Y and Zr; 6 ppm for Nb; 10 ppm for Ba; 13 ppm for Pb; and 14 ppm for Th. The time taken for determining Sc, V, Cr, Co, Ni, Cu, Zn, Rb, Sr, Y, Zr, Nb, Ba, Pb, and Th in a batch of 24 samples of komatiites, for a replication of four analyses per sample, by one operator, using a manual WDXRF spectrometer, is only 60 hours. 相似文献
14.
Most sulfide-rich magmatic Ni-Cu-(PGE) deposits form in dynamic magmatic systems by partial melting S-bearing wall rocks with variable degrees of assimilation of miscible silicate and volatile components, and generation of barren to weakly-mineralized immiscible Fe sulfide xenomelts into which Ni-Cu-Co-PGE partition from the magma. Some exceptionally-thick magmatic Cr deposits may form by partial melting oxide-bearing wall rocks with variable degrees of assimilation of the miscible silicate and volatile components, and generation of barren Fe ± Ti oxide xenocrysts into which Cr-Mg-V ± Ti partition from the magma. The products of these processes are variably preserved as skarns, residues, xenoliths, xenocrysts, xenomelts, and xenovolatiles, which play important to critical roles in ore genesis, transport, localization, and/or modification. Incorporation of barren xenoliths/autoliths may induce small amounts of sulfide/chromite to segregate, but incorporation of sulfide xenomelts or oxide xenocrysts with dynamic upgrading of metal tenors (PGE > Cu > Ni > Co and Cr > V > Ti, respectively) is required to make significant ore deposits. Silicate xenomelts are only rarely preserved, but will be variably depleted in chalcophile and ferrous metals. Less dense felsic xenoliths may aid upward sulfide transport by increasing the effective viscosity and decreasing the bulk density of the magma. Denser mafic or metamorphosed xenoliths may also increase the effective viscosity of the magma, but may aid downward sulfide transport by increasing the bulk density of the magma. Sulfide wets olivine, so olivine xenocrysts may act as filter beds to collect advected finely dispersed sulfide droplets, but other silicates and xenoliths may not be wetted by sulfides. Xenovolatiles may retard settling of – or in some cases float – dense sulfide droplets. Reactions of sulfide melts with felsic country rocks may generate Fe-rich skarns that may allow sulfide melts to fractionate to more extreme Cu-Ni-rich compositions. Xenoliths, xenocrysts, xenomelts, and xenovolatiles are more likely to be preserved in cooler basaltic magmas than in hotter komatiitic magmas, and are more likely to be preserved in less dynamic (less turbulent) systems/domain/phases than in more dynamic (more turbulent) systems/domains/phases. Massive to semi-massive Ni-Cu-PGE and Cr mineralization and xenoliths are often localized within footwall embayments, dilations/jogs in dikes, throats of magma conduits, and the horizontal segments of dike-chonolith and dike-sill complexes, which represent fluid dynamic traps for both ascending and descending sulfides/oxides. If skarns, residues, xenoliths, xenocrysts, xenomelts, and/or xenovolatiles are present, they provide important constraints on ore genesis and they are valuable exploration indicators, but they must be included in elemental and isotopic mass balance calculations. 相似文献
15.
《Applied Geochemistry》2001,16(2):137-159
Five hundred and ninety-eight samples of terrestrial moss (Hylocomium splendens and Pleurozium schreberi) collected from a 188,000 km2 area of the central Barents region (NE Norway, N Finland, NW Russia) were analysed by ICP-AES and ICP-MS. Analytical results for Al, B, Ba, Ca, K, La, Mg, Mn, Na, P, Rb, Si, Sr, Th, U and Y concentrations are reported here. Graphical methods of data analysis, such as geochemical maps, cumulative frequency diagrams, boxplots and scatterplots, are used to interpret the origin of the patterns for these elements. None of the elements reported here are emitted in significant amounts from the smelting industry on the Kola Peninsula. Despite the conventional view that moss chemistry reflects atmospheric element input, the nature of the underlying mineral substrate (regolith or bedrock) is found to have a considerable influence on moss composition for several elements. This influence of the chemistry of the mineral substrate can take place in a variety of ways. (1) It can be completely natural, reflecting the ability of higher plants to take up elements from deep soil horizons and shed them with litterfall onto the surface. (2) It can result from naturally increased soil dust input where vegetation is scarce due to harsh climatic conditions for instance. Alternatively, substrate influence can be enhanced by human activity, such as open-cast mining, creation of ‘technogenic deserts’, or handling, transport and storage of ore and ore products, all of which magnify the natural elemental flux from bedrock to ground vegetation. Seaspray is another natural process affecting moss composition in the area (Mg, Na), and this is most visible in the Norwegian part of the study area. Presence or absence of some plant species, e.g., lichens, seems to influence moss chemistry. This is shown by the low concentrations of B or K in moss on the Finnish and Norwegian side of the (fenced) border with Russia, contrasting with high concentrations on the other side (intensive reindeer husbandry west of the border has selectively depleted the lichen population). 相似文献
16.
Mercury,arsenic, antimony,and selenium contents of sediment from the Kuskokwim River,Bethel, Alaska,USA 总被引：1，自引：0，他引：1
The Kuskokwim River at Bethel, Alaska, drains a major mercury-antimony metallogenic province in its upper reaches and tributaries. Bethel (population 4000) is situated on the Kuskokwim floodplain and also draws its water supply from wells located in river-deposited sediment. A boring through overbank and floodplain sediment has provided material to establish a baseline datum for sediment-hosted heavy metals. Mercury (total), arsenic, antimony, and selenium contents were determined; aluminum was also determined and used as normalizing factor. The contents of the heavy metals were relatively constant with depth and do not reflect any potential enrichment from upstream contaminant sources. 相似文献
17.
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S. M. Moosavirad J. Rasouli M. R. Janardhana M. R. Moghadam M. Shankara 《Arabian Journal of Geosciences》2013,6(10):3623-3634
This paper discusses the result of the detailed investigations carried out on the coal characteristics, including coal petrography and its geochemistry of the Pabedana region. A total of 16 samples were collected from four coal seams d2, d4, d5, and d6 of the Pabedana underground mine which is located in the central part of the Central-East Iranian Microcontinent. These samples were reduced to four samples through composite sampling of each seam and were analyzed for their petrographic, mineralogical, and geochemical compositions. Proximate analysis data of the Pabedana coals indicate no major variations in the moisture, ash, volatile matter, and fixed carbon contents in the coals of different seams. Based on sulfur content, the Pabedana coals may be classified as low-sulfur coals. The low-sulfur contents in the Pabedana coal and relatively low proportion of pyritic sulfur suggest a possible fresh water environment during the deposition of the peat of the Pabedana coal. X-ray diffraction and petrographic analyses indicate the presence of pyrite in coal samples. The Pabedana coals have been classified as a high volatile, bituminous coal in accordance with the vitrinite reflectance values (58.75–74.32 %) and other rank parameters (carbon, calorific value, and volatile matter content). The maceral analysis and reflectance study suggest that the coals in all the four seams are of good quality with low maceral matter association. Mineralogical investigations indicate that the inorganic fraction in the Pabedana coal samples is dominated by carbonates; thus, constituting the major inorganic fraction of the coal samples. Illite, kaolinite, muscovite, quartz, feldspar, apatite, and hematite occur as minor or trace phases. The variation in major elements content is relatively narrow between different coal seams. Elements Sc,, Zr, Ga, Ge, La, As, W, Ce, Sb, Nb, Th, Pb, Se, Tl, Bi, Hg, Re, Li, Zn, Mo, and Ba show varying negative correlation with ash yield. These elements possibly have an organic affinity and may be present as primary biological concentrations either with tissues in living condition and/or through sorption and formation of organometallic compounds. 相似文献
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