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Partitioning of Se, As, Sb, Te and Bi between monosulfide solid solution and sulfide melt - Application to magmatic sulfide deposits 总被引:1,自引:0,他引:1
Hassan M. Helmy Chris Ballhaus Raúl O.C. Fonseca 《Geochimica et cosmochimica acta》2010,74(21):6174-6179
The chalcogenes (S, Se, Te), semimetals (As, Sb) and the metal Bi are important ligands for noble metals and form a wide range of compositionally diverse minerals with the platinum-group elements (PGE). With the exception of S, few experimental data exist to quantify the behavior of these elements in magmatic sulfide systems. Here we report experimental partition coefficients for Se, Te, As, Sb, and Bi between monosulfide solid solution (mss) and sulfide melt, determined at 950 °C at a range of sulfur fugacities (fS2) bracketed by the Fe-FeS (metal-troilite) and the Fe1−×S-Sx (mss-sulfur) equilibria. Selenium is shown to partition in mss-saturated sulfide melt as an anion replacing S2−. Arsenic changes its oxidation state with fS2 from predominantly anionic speciation at low fS2, to cationic speciation at high fS2. The elements Sb, Te, and Bi are so highly incompatible with mss that they can only be present in sulfide melt as cations and/or as neutral metallic species. The partition coefficients derived fall with increasing atomic radius of the element. They also reflect the positions of the respective elements in the Periodic Table: within a group (e.g., As, Sb, Bi) the partition coefficients fall with increasing atomic radius, and within a period the elements of the 15th group are more incompatible with mss than the neighboring elements of the 16th group. 相似文献
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用原子荧光法同时测定砷、锑、铋、汞 总被引:8,自引:0,他引:8
试样经王水分解 ,在HCl (1+ 9)介质中 ,用硫脲 抗坏血酸将 5价As、Sb还原为 3价 ,再用KBH4 还原为氢化物。在HCl (1+ 4 )介质中 ,与KBH4 作用生成AsH3、SbH3、BiH3和Hg ,以特制空心阴极灯为光源 ,用双道无色散原子荧光仪测定As、Sb、Bi、Hg的荧光强度 ,各元素的检出限分别为As 5 9× 10 - 10 ,Sb 5 0× 10 - 10 ,Bi 6 9× 10 - 10 ,Hg 2 9× 10 - 1 相似文献
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土壤重金属污染物的环境效应与其无机价态有密切的关系。As、Cr、Sb和Se元素的价态测定意义重大,但由于价态之间易发生转化使测定工作存在较大难度,标准化程度较低。地质行业标准DD2005-3推荐使用离子交换树脂分离,原子荧光光谱差减法测定As、Sb、Se价态及石墨炉原子吸收光谱法(GFAAS)测定Cr价态。这些方法前处理操作繁琐,测定次数多,工作量大,其他元素形态的存在还会导致结果出现误差。为满足地质调查和评价的需要,本文建立了一套适用于测定土壤水溶态和离子交换态提取液中As、Cr、Sb、Se价态的方法。样品在50℃水浴振荡加热浸提30min,采用液相色谱-原子荧光光谱法(LC-AFS)分离并测定As、Sb、Se价态,一次进样元素的两种无机价态按顺序出峰,同时测定,简便易行,结果更可靠。为了避免了某些离子交换提取剂的屏蔽和干扰,作为补充建立了AFS选择性测定Sb、Se价态的方法,设备成本较低。对于Cr价态的测定,建立了阳离子交换树脂分离-电感耦合等离子体质谱(ICP-MS)的方法,比推荐的GFAAS测定法灵敏度高。As、Cr、Sb和Se的检出限≤0.02μg/g,RSD为3.8%~10.7%,加标回收率为91.0%~106.0%。应用色谱方法对采集的土壤样品进行检测,各项指标满足规范DD2005-3质量要求,与非色谱法相比,实现多组分同时测定。同时初步研究表明,土壤中元素价态含量不高,与土壤总量不存在相关性,采用价态含量作为环境风险评估指标更为合适。 相似文献
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多目标生态地球化学调查土壤样品中砷硒锑有效态分析方法的商榷 总被引:5,自引:2,他引:5
以0.10mol/L NaH2PO4和0.50mol/L NaHCO3为浸提剂,试验了其对土壤样品中As、Se、Sb的浸提效果;以氢化物发生-原子荧光法(HG-AFS)测定了浸提液中As、Se、Sb的含量。方法在武汉、宁镇测区应用试验表明:采用0.50mol/L的NaHCO3为As、Se、Sb的有效态浸提剂,以HG—AFS法测定其含量的方案可行,检出限分别为:0.006mg/kg、0.001mg/kg、0.002mg/kg。精密度试验,6个标准样品的RSD(n=12)As、Se、Sb均≤10.15%。 相似文献
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Analytical data are reported for As, Bi, Sb, Se and Te in fifty five geological reference materials (RM). The method used is based on hydride generation inductively coupled plasma-mass spectrometry (HG-ICP-MS) following digestion of the samples in the mixed acid attack of HF-HClO4-HNO3-HCl. Analytes were separated from potential interferences by coprecipitation with La(OH)3. This scheme results in method detections limits of: 1 ng g?1 for Bi and Te; 6 ng g?1 for Sb and Se; and 10 ng g?1 for As. The average relative standard deviation (RSD) for three 0.5 g subsamples of each RM analysed by this method are: 3.7% for As in the range 0.35-187 μg g?1; 5.6% for Sb in the range 0.03-22 μg g?1; 6.8% for Bi in the range 0.002-48 μg g?1; 7.2% for Se in the range 6-3610 ng g?1; and 9.0% for Te in the range 2-445 ng g?1. 相似文献
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Tellurides have been identified in VMS mineralization at Yuinmery and Austin in the Archean Youanmi Terrane, Yilgarn Craton, Western Australia. Tellurides identified at Yuinmery include: petzite, stützite, hessite, tellurobismuthite, altaite, rucklidgeite, melonite, mattagamite and a nickel-cobalt telluride with chemical composition similar to cobaltian melonite which has previously only been reported once before. Tellurides and related minerals identified at Austin include: stützite, volynskite, tellurobismuthite, tetradymite, tsumoite, rucklidgeite, altaite and a mineral with the formula (Bi,Pb)3(Te,Se,S)4 corresponding to the rare mineral poubaite. The tellurides are interpreted to have been deposited with the base metals on and immediately below the sea floor by very hot fluids during a period of quiescence in the volcanism. The mineral assemblage suggests that the fluids in both areas had high ƒTe2 and were oxidising but close to the pyrrhotite-pyrite boundary. The presence of Ni and Co tellurides at Yuinmery but not at Austin is probably due to the derivation of the fluids at Yuinmery from mafic volcanism whereas at Austin the succession is dominantly felsic. The metamorphic grade at Austin is higher than that at Yuinmery and this may have resulted in some re-crystallization of tellurides and tellurosulfides. 相似文献
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原子荧光光度法分析As、Sb、Bi已被广泛应用,但由于仪器没有色散系统,所以干扰因素较多。阐述了原子荧光光度分析法中常见的干扰及其消除方法。方法简单、快速、灵敏、低耗。 相似文献
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Based on the synthesis of hydrogeochemical materials on Sb occurrence in carbonate and thermal waters and thermodynamic simulations, genetic analysis was conducted of the transformations of probable Sb migration species (particularly oxygen-bearing and sulfide ones), and their transformations were calculated depending on the main parameters of hydrogeochemical systems (\(P_{CO_2 } \), T, R/W, Eh, and pH). The oxygen 2HSbO 2 0 + 3H2S = Sb2S3 + 4H2O (2SbO 2 ? + 3HS? + 5H+ = Sb2S3 + 4H2O) and sulfide HSb2S 4 ? + H+ = Sb2S3 cr + H2S (Sb2S 4 2? + 2H+ = Sb2S3cr + H2S) models for the genesis of hydrogenic Sb2S3(cr) were simulated. Information on occurrences of carbonate and thermal waters in various regions worldwide was generalized, and the reasons were identified for the geochemical separation of As and Sb in carbonate and thermal waters. The causes and conditions of an increase in Sb concentrations in thermal waters were revealed, and Sb migration species in carbonate and thermal waters were identified for various parameters of hydrogeochemical systems. Variations in Sb speciation were demonstrated for hydrogeochemical systems depending on their boundary conditions (\(P_{CO_2 } \), T, and R/W). Models were outlined responsible for the precipitation of Sb2S3(cr) from carbonate and thermal waters. 相似文献
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Increasing emphasis is being given to the search for blind mineral deposits and the presence of geochemical dispersion halos in wallrocks may significantly enhance the chances of exploration success. Accordingly, the nature of wallrock dispersion associated with the Lake Dufault Cu-Zn-Au-Ag massive sulphide deposit, Noranda, Quebec, was examined to see if any such patterns existed. On the basis of relatively well defined geology, the area offered an opportunity to establish the relation between geochemical alteration and metallogeny, texture, structure and mineralogy.Anomalous element contents spatially related to mineralization are confined to the stratigraphic footwall (Waite Rhyolite) where Na2O, SiO2 and possibly CaO depletions and total Fe1 Mn and MgO enrichments can be related to the hydrothermal vent. Dispersion halos 150–500 m in diameter are at least twice as wide as the obvious mineralogical alteration halo. Cu, Zn, Ag and S distributions show roughly similar patterns which are not obviously related to the main alteration pipe but do reveal broad enrichment zones in the general area of mineralization.The dispersion appears to be partly controlled by texture. Because of greater primary permeability, the halos produced in rhyolite breccia are wider and better defined than those in more massive rhyolites. On a wider scale (10 km2) dispersion patterns are related to the fault and fracture systems of the area.As many as five stages of metamorphism have affected the area, altering all rocks to some extent. Samples can be classified petrographically into alteration groups, both related and unrelated to mineralization. Comparison of these groups reveals the inadequacy of certain elements for outlining alteration related to mineralization. For example, the range of K2O in relatively unaltered rhyolite overlaps the composition of all other groups, including those related to mineralization. Similarly apparent is that the distribution of certain elements, e.g., Na2O, may adequately define one part of an alteration zone such as the sericite-rich zone, but not another.It is concluded that careful use of lithogeochemistry in conjunction with detailed geological mapping and core logging can provide information otherwise obtainable only by time-consuming petrographic analysis. Thus it can be a potent weapon in the search for blind ore deposits. 相似文献
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Geochemical investigations have shown that the nickel sulphide mineralisation at Kambalda is detectable by sampling and analysing the minus 80-mesh fraction of near-surface soils. Over unmineralised mafic and ultramafic rocks the distribution of Ni in soils accurately reflects bedrock Ni distribution. In the environment of sulphide mineralisation Ni is preferentially concentrated in the coarse fractions of the soils, with a corresponding depletion in the minus 80-mesh fraction. Both Ni and Cu nevertheless display strong anomalies in minus 80-mesh fraction soils in the immediate vicinity of sub-outcropping mineralisation. 相似文献
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原子荧光光谱分析环境样品中砷锑铋汞易出现的问题及解决方法 总被引:2,自引:0,他引:2
针对原子荧光光谱法测试砷锑铋汞中易出现的仪器空白不稳定、样品制备及仪器污染等问题,总结出相应的解决方法。 相似文献
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针对原子荧光光谱法测试中易出现的仪器不稳、标准工作曲线线性不佳、重现性不好等问题,提出了相应的处理办法。 相似文献
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不同氢化反应条件下原子发射光谱同时测定锗锡砷锑铋 总被引:7,自引:0,他引:7
研究了不同氢化反应条件下电感耦合等离子体原子发射光谱同时测定锗,,锡,砷,锑和铋的方法。主要对锗,锡的氢化反应酸度,缓冲溶液的选择,动态线性范围,氧化剂的选择,共存元素的干扰及其消除进行实验。方法经国家一级标准物质分析验证,结果与标准值基本相符。 相似文献
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We determine the valence electron density and the electron band structure of stibnite, bismutinite, guanajuatite and antimonelite using the density functional theory. All the compounds present similar electronic properties and exhibit a quasi-1D character. We perform a detailed analysis of the charge topology, the atomic static charges and volumes. 相似文献
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氢化物发生-电感耦合等离子体发射光谱法同时测定土壤中痕量砷锑铋汞 总被引:4,自引:4,他引:0
土壤样品用水浴加热王水溶解1 h,在10%的盐酸介质下,用0.5 L/min的载气流量,10 g/L的硼氢化钠-氢氧化钠作为还原剂,将自行设计的一种新型氢化物发生器与电感耦合等离子体发射光谱法(ICP-AES)联用测定痕量砷、锑、铋、汞,一次溶样即可实现多元素在同母液同条件下同时测定。方法检出限为0.01~0.06 ng/g,加标回收率为92.0%~102.0%,精密度(RSD)低于5%。此方法通过加入抗坏血酸-硫脲溶液预先将砷和锑还原,汞的测定不受还原剂的影响,同时解决了目前多元素分次测量带来的不便和试剂消耗多等问题,样品前处理及测量过程快速、简单,无记忆效应的影响,适合环境样品中痕量砷、锑、铋、汞的同时测定。 相似文献
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The Zheyaoshan deposit is the largest within the Baiyinchang (BYC) volcanic-hosted massive sulfide (VHMS) district, located in the northern Qilian orogenic belt of North China. The deposit is hosted by quartz keratophyre tuffs, with wall-rock alteration mainly comprising chlorite, sericite, quartz, pyrite and epidote. Mineral assemblages within the altered host rocks can be divided into a sericite-quartz-dominant assemblage (sericite-silicified zone), a chlorite-dominant assemblage (chlorite-dominant zone) and a pyrite-dominant assemblage (mineralized zone) based on geochemical analysis and alteration characteristics. We have conducted detailed processing and critical analysis of the geochemical data of both the altered and least-altered host rocks in order to investigate the problem of closure in the geochemical dataset to eliminate the influence that each component has on the other in terms of mass change, and have applied the standardized method of the mass change calculation to analyze this data. The results show that: (1) the sericite-silicified zone formed along fissures due to the ingress of hydrothermal fluids, with MnO2, Na2O and CaO being mobilized into the hydrothermal fluids leached and MgO, Fe2O3, SiO2, K2O, BaO deposited. Additionally, Ag, Cu and chalcophile elements (Ag, As and Bi) were enriched while Pb, Zn and large ion lithophile elements (LILEs) (Cs, Sr, Eu, Be) were mobilized into hydrothermal fluids; (2) the physiochemical conditions and pH levels of the hydrothermal fluids changed during sericitization, with MgO, Fe2O3, BaO being further enriched and MnO, Na2O, CaO further depleted, leading to formation of chlorite and the initial precipitation of metallogenic the (Cu, Zn, Pb) and chalcophile elements (Ag, As, Bi); (3) the negative Eu anomaly was mainly due to its strong activity when Eu is mobilized into the hydrothermal fluids during since plagioclase break-down during the sericite-silicification process; (4) AI and CCPI values gradually increase towards the orebody. The chlorite-dominant assemblage and sericite-quartz-dominant assemblage on the periphery of the chlorite-dominant zone can all be used as vectors towards the volcanic massive sulfide orebody and for regional-scale mineral exploration. Either leached elements or enriched elements can be considered as significant indicator elements and as prospective indicators for geochemical exploration within the BYC district. The Eu anomaly may be especially useful as an indicator for distinguishing the least-altered rocks which has great significance for exploration on the regional scale. 相似文献