Modes of Occurrence and Cleaning Potential of Trace Elements in Coals from the Northern Ordos Basin and Shanxi Province, China

Based on the analyses of 43 elements in 16 samples of the raw coal and feed coal collected from the northern Ordos basin and Shanxi Province, the modes of occurrence of these elements were studied using the method of cluster analysis and factor analysis, and the cleaning potential of the hazardous elements relatively enriched in the coals was discussed by analyzing six samples of the cleaned coal from the coal-washing plants and coal cleaning simulation experiments. The results shows that the elements Br and Ba show a strong affinity to the organic matter, Cs, Cd, Pb, Zn and Hg partly to the organic matter, and the other trace elements are mainly associated with the mineral matter. Cs, Mo, P, Pb, Zn and S have positive correlations with the two principal factors, reflecting the complexity of their modes of occurrence. Some elements that were thought to show a faint relationship (Be with S and Sb with carbonates) in other rocks are found to have a strong interrelation in the coals. Clay minerals (mainly kaolinite) dominate in the coals, and Ta, Th, Ti, Sc, REE, Hf, U, Se, W, V, Nb, Mo, Al, P, Cr, Pb and Zn are distributed mostly in kaolinite, while K, Rb, Cs, and Na have much to do with illite. Conventional cleaning can reduce the concentrations of most hazardous elements in various degrees. The hazardous elements S, As, Sb, Se, Mo, Pb, Cd and Hg relatively enriched in some coals from the area studied have a relatively high potential of environmental risks. However, by physical coal cleaning processes, more than 60% of As and Hg were removed, showing a high degree of removal, more than 30% of Sb, as well as S, Pb and Cd partly associated with the inorganic matter were removed. Se and Mo showing a relatively low degree of removal could be further removed by deep crushing of the coal during physical cleaning processes, and the concentrations of S, Pb, Cd and Hg with a partial association with the organic matter could be decreased in such ways as the coal blending. Cluster analysis together with factor analysis is a rapid and effective way to deduce the mode of occurrence of an element from bulk samples, and the removability data of most hazardous elements are basically consistent with their modes of occurrence suggested, which indicates that the statistical analysis could predict the cleaning potential of hazardous elements during the physical coal cleaning.

Geochemistry and Modes of Occurrence of Hazardous Trace Elements in the No.11 Coal Seam,Antaibao Surface Mine,Shanxi Province

Concentrations of seventeen hazardous trace elements including As, Pb, Hg, Se, Cd, Cr, Co, Mo, Mn, Ni, U, V, Th, Be, Sb, Br and Zn in the No.ll coal seam, Antaibao surface mine, Shanxi Province were determined using Instrumental Neutron Activation Analysis （INAA）, Inductively Coupled Plasma Atomic Emission Spectrometry （ICP-AES）, Cold-Vapor Atomic Absorption Spectrometry （CV-AAS） and Graphite Furnace Atomic Absorption Spectrometry （GF-AAS）. Comparisons with average concentrations of trace elements in Chinese coal show that the concentrations of Hg and Cd in the No. 11 coal seam, Antaibao surface mine are much higher. They may be harmful to the environment in the process of utilization. The variations of the trace elements contents and pyritic suffur in vertical section indicated that： （a） the concentrations of As, Pb, Mn, and pyritic sulfur decrease from roof to floor; （b） the concentrations of Cr, Zn and Mo are higher in roof, floor and lower in coal seam; （c） the concentration of Br, Sb, and Hg are higher in coal seam and lower in roof and floor; （d） the concentrations of Mo, V, Th and AI vary consistently with the ash yield. Cluster analysis of trace elements, pyritic sulfur, ash yield and major elements, such as AI, Fe, P, Ca shows that： （a） pyritic sulfur, Fe, As, Mn, Ni, Be are closely associated and reflect the influence of pyrite; （b） Mo, Se, Pb, Cr, Th, Co, Ca and A! are related to clay mineral, which is the main source of ash; （c） U, Zn, V, Na, P maybe controlled by phosphate or halite; （d） Hg, Br, Sb and Cd may be mainly organic-associated elements which fall outside the three main groups. The concentration distribution characteristics of trace elements in coal seam and the cluster analysis of major and trace elements showed that the contents of trace elements in the No. 11 coal seam, Antaibao surface mine, are mainly controlled by detrital input and migration from roof and floor.

Mineralogy,distribution,occurrence and removability of trace elements during the coal preparation of No.6 coal from Heidaigou mine

Optical microscopy and scanning electron microscopy in conjunction with energy dispersed X-ray spectrometry(SEM–EDX)were used to study the minerals and the concentrations of 33 trace elements in No.6 coal from Heidaigou mine.The distributions,organic affinity and removability of 18 trace elements were studied by float-sink experiments.A determination of the maceral groups was also undertaken.A high mineral content,dominated by kaolinite,was found in No.6 coal from Heidaigou mine.The bauxite content was relatively high and it was mainly present as individual particles in fusinite lumens or was intimately intergrown with carbonate minerals.The pyrite and quartz contents were low.Some marcasite with a parallel twin structure was observed by cross-polar reflected light.A small amount of bean-like goyazite was present in the calcite.The weighted trace element content in Heidaigou formations is relatively low,which is beneficial for coal processing and utilization.The concentrations of Ga,Hg,Pb,Se,Th,Ta are relatively high compared with the average values of Chinese coals.As,Hg,Mo,Ge,Ga,Ta,Ti,W,Mn are mainly present in minerals while B,Be,Th,P,Sc,Sr,V,Y,Yb are mainly found in organic matter.As,Ge,Hg,Mo are mainly present in sulfides and Be,Th,P,Sc,Sr,Y,Yb are mainly present in inertinite.B and V are mainly present in vitrinite.The high organic affinity and the low theoretical removability of most trace elements cause difficulties in removing them during coal preparation.

Distribution and occurrence of trace elements in the No.14 coal from the Huolinhe mine

Optical microscopy, and scanning electron microscopy in conjunction with energy dispersed X-ray spectrometry （SEM-EDX）, have been used to study the minerals and the concentrations of 12 trace elements in the No.14 coal from the Huolinhe mine, Inner Mongolia China. The distribution, affinity and removability of the trace elements were studied by float-sink experiments and petrological methods. A high mineral content, dominated by clay minerals, was found in the No.14 coal from the Huolinhe mine. The concentrations of As, Sb and Hg are relatively high compared to the average values for Chinese coals. As, Cr, Hg, Li, Mn, Pb are mainly associated with the minerals while Cd, Co, Ni, Sb, and Se are evenly distributed between the minerals and the organic matter. Be and Ba are mainly distributed in the minerals with a minor proportion in the organic matter. Most elements have a low organic affinity, although Sb, Se, Co, Cd, Ni are closely integrated with the organic matter. High theoretical removabilities are indicated for most trace elements. So it may be possible to lower the concentrations of trace elements during coal preparation.

Effect of occurrence mode of heavy metal elements in a low rank coal on volatility during pyrolysis

The harmful trace elements will be released during coal utilization, which can cause environment pollution and further endangering human health, especially for heavy metal elements. Compared to combustion, the release of heavy metal elements during coal pyrolysis process, as a critical initial reaction stage of combustion, has not received sufficient attention. In the present paper, a low rank coal, from Xinjiang province in China, was pyrolyzed in a fixed bed reactor from room temperature, at atmospheric pressure, with the heating rate of 10 °C/min, and the final pyrolysis temperature was from 400 to 800℃ with the interval of 100℃. The volatility of heavy metal elements (including As, Hg, Cd and Pb) during pyrolysis process was investigated. The results showed the volatility of all heavy metal elements increased obviously with increasing temperature, and followed the sequence as Hg > Cd > As > Pb, which was mainly caused by their thermodynamic property and occurrence modes in coal. The occurrence modes of heavy metals were studied by sink-andfloat test and sequential chemical extraction procedure, and it can be found that the heavy metal elements were mainly in the organic and residual states (clay minerals) in the raw coal. And most of the organic heavy metals escaped during the pyrolysis process, the remaining elements were mainly in the residual state, and the elements in Fe-Mn state also tended to remain in the char.

Occurrence and volatility of several trace elements in pulverized coal boiler

The contents of eight trace elements(Mn, Cr, Pb, As, Se, Zn, Cd, Hg) in raw coal, bottom ash and fly ash were measured in a 220 t/h pulverized coal boiler. Factors affecting distribution of trace elements were investigated, including fly ash diameter, furnace temperature, oxygen content and trace elements' characters. One coefficient of Meij was also improved to more directly show element enrichment in combustion products. These elements may be classified into three groups according to their distribution: Group 1: Hg, which is very volatile. Group 2: Pb, Zn, Cd, which are partially volatile. Group 3: Mn, which is hardly volatile. Se may be located between groups 1 and 2 Cr has properties of both group 1 and 3 In addition, the smaller diameter of fly ash, the more relative enrichment of trace elements(except Mn). The fly ash showed different adsorption mechanisms of trace elements and the volatilization of trace elements rises with furnace temperature. Relative enrichments of trace elements(except Mn and Cr) in fly ash are larger than that in bottom ash. Low oxygen content can not always improve the volatilization of trace elements. Pb is easier to form chloride than Cd during coal combustion. Trace elements should be classified in accordance with factors.

Enrichment Characteristics, Occurrence and Origin of Valuable Trace Elements in Lignite from Linchang Coal Mine, Guangxi, China

To evaluate the comprehensive exploitation and utilization values of coal resources in Baise basin of Guangxi, the Paleogene coal of Linchang coal mine were sampled and studied. The enrichment characteristics, occurrence modes, and geochemical origin of valuable trace elements in coal were studied by using X-ray diffraction (XRD), scanning electron microscope-energy dispersive X-ray spectrometer (SEM-EDS), polarizing microscope, X-ray fluorescence spectrometry (XRF), inductively coupled plasma mass spectrometry (ICP-MS) and atomic fluorescence spectrometry (AFS). The results reveal that Linchang coal is ultra-low calorific value lignite with high ash, medium sulfur, medium-high moisture and medium volatilization. The minerals are mainly composed of illite, kaolinite, quartz, pyrite, siderite, bassanite, anhydrite and magnesium-containing calcite. Compared with average values for world low-rank coals, the contents of valuable trace elements in Linchang coal are higher on the whole, which is characterized by the high enrichment of U, the enrichment of elements Li, V and Ag, and the slight enrichment of elements Be, Ga and Se. Lithium, V, Ga and Ag mainly occur in clay minerals including illite and kaolinite, and part of V is related to organic matter. The carriers of Be in coal are clay minerals and organic matter. Selenium is mainly combined with organic matter and a small amount exists in pyrite. Uranium is primarily organically bound in coal. The enrichment of valuable trace elements in Linchang coal is influenced by the sedimentary source, coal-forming environment, underground circulating water and geological structure. The sedimentary environment of the coal seam is an acid-reduced terrestrial peat swamp, and the source is Triassic sedimentary rocks weathered from feldspathic volcanic rocks around Baise basin.

Organic/ Inorganic Occurrence of Metallic Elements of the Black Shale-Hosted Baiguoyuan Silver-Vanadium Deposit in Xingshan, Hubei

: By means of kerogen purification, the proton induced X-ray emission (PIXE) and instrumental neutron activation analysis (INAA), the authors have studied the organic/inorganic occurrence modes of the metallic elements of the Baiguoyuan silver-vanadium deposit hosted in black shale in Hubei Province, China. The result shows that Au, Hg and Ta have a strong tendency to occur organically, with more than 70% of these elements being associated organically. Se, Ga, Ag and Hf are partly associated with organic matter, with more than 20% of them occurring organically. Compared with the above elements, Zn, Cu, As and Sb are weakly associated organically, and tend to be enriched in kerogen. However, Mn, Th, U, V, Co, Cr, AI, Fe and Sc usually occur inorganically. Of the rare earth elements (REE), La, Ce, Tb, Dy, Yb and Lu have stronger ability to be associated with organic matter than Sm and Eu.

Distribution and Relationships of Seven Trace Elements （Cr, Fe, Mn, Ni, Co, Cu and Zn） in Freshwater Fish from Five French Fishing Areas

The concentrations of seven essential trace elements in 149 freshwater fish from eight fish species （European eel, bream, common carp, European catfish, roach, perch, pike and pikeperch） from five different French fishing areas from contaminated and control sites were measured by inductively coupled plasma mass spectrometry after microwave digestion under pressure. Differences in the concentration of elements in the muscles of these species were examined and the mean levels were compared for each species with previous French and European studies. The condition factor and the differences between the control and contaminated sites and between predatory and non-predatory groups, with respect to the concentration of these elements, were also studied.

Elemental characteristics and paleoenvironment reconstruction： a case study of the Triassic lacustrine Zhangjiatan oil shale, southern Ordos Basin, China

Using trace elements to reconstruct paleoenvironment is a current hot topic in geochemistry. Through analytical tests of oil yield, ash yield, calorific value, total sulfur, major elements, trace elements, and X-ray diffraction, the quality, mineral content, occurrence mode of elements, and paleoenvironment of the Zhangjiatan oil shale of the Triassic Yanchang Formation in the southern Ordos Basin were studied. The analyses revealed relatively high oil yield(average 6.63%) and medium quality. The mineral content in the oil shale was mainly clay minerals,quartz, feldspar, and pyrite; an illite–smectite mixed layer comprised the major proportion of clay minerals. Compared with marine oil shale in China, the Zhangjiatan oil shale had higher contents of quartz, feldspar, and clay minerals, and lower calcite content. Silica was mainly in quartz and Fe was associated with organic matter, which is different from marine oil shale. The form of calcium varied. Cluster analyses indicated that Fe, Cu, U, V, Zn, As,Cs, Cd, Mo, Ga, Pb, Co, Ni, Cr, Sc, P, and Mn are associated with organic matter while Ca, Na, Sr, Ba, Si, Zr, K,Al, B, Mg, and Ti are mostly terrigenous. Sr/Cu, Ba/Al, V/(V+ Ni), U/Th, AU, and δU of oil shale samples suggest the paleoclimate was warm and humid, paleoproductivity of the lake was relatively high during deposition of the shale—which mainly occurred in fresh water—and the paleo-redox condition was dominated by reducing conditions. Fe/Ti ratios of the oil shale samples suggest clear hydrothermal influence in the eastern portion of the study area and less conspicuous hydrothermal influence in the western portion.

Geochemical characteristics of the coal gangues from the Du'erping coal mine, Xishan coalfield, North China

Inductively coupled plasma mass spectrometry, inductively coupled plasma optical emission spectroscopy, hydride generation-atomic fluorescence spectrometry, emission spectrometry, X fluorescence spectrometry, and X-ray diffraction were employed to study the geochemistry and mineralogy of coal gangues from Nos. 2, 3, and 8 coal seams of the Du'erping coal mine, Xishan coalfield, Taiyuan, Shanxi Province. The study revealed that compared with the sedimentary cover, upper continent crust, Carboniferous-Permian coal from North China, as well as most coal in China, coal gangues from Nos. 2 and 3 coal seams are rich in Li, Be, Sc, Cr, Cu, Ga, Ba, Th, Nb, Cd, Pb, Ta and rare-earth elements, and coal gangues from No. 8 coal seam are rich in Li, Sc, V, Cr, Ga, U, and rare-earth elements. Compared with the Carboniferous-Permian coal from North China and most coal in China, coal gangues from Nos. 2, 3 and 8 seams are rich in Rb, V, Cs and Sr. Therefore, The Du'erping coal gangues in the Xishan coalfield are rich in most hazardous trace elements and rare-earth elements, wherein the contents of Ga and Li reach the industrial grade and have significance for industrial utilization. On the whole, coal gangues of the Shanxi Formation from the Permian are rich in more trace elements than those of the Carboniferous Taiyuan Formation. The distributions of REE show obviously dipping rightwards with negative Eu anomalies. The contents of rare-earth elements in the three seams are quite different. All of the above indicate that the source of the rare-earth elements is terrigenous debris. Minerals in No. 2 seam identified by X-ray diffraction mainly include quartz, kaolinite, in addition to calcite, pyrite, apatite, epidote, and epsomite. No. 3 seam mainly contains quartz, kaolinite, in addition to a small amount of sodium feldspar, calcium nitrate, iron ore, gypsum, and vivianite. No. 8 seam mainly contains kaolinite, dickite, quartz, illite, and a small amount of hematite and U. The correlations between major elements and trace elements in coal gangues of the Du'erping coal mine analyzed by using SPSS (Statistical Product and Service Solutions) indicate that the trace alkali elements and rare-earth elements occur mainly in such clay minerals as kaolinite.

Modes of occurrence and pre-concentration of rare earth elements in No.17 coal in Liupanshui coalfield,China

Rare earth elements(lanthanide and yttrium,abbreviated as REY) provide important support for national security,energy production,environmental protection and economic growth.In recent years,many studies have shown that the content of REY in some coal or coal by-products is close to or even higher than that in traditional REY ore,which makes coal a potential source of REY.This study took the No.17 coal of Panzhou mining area in Liupanshui coal field as the research object,and the content and occurrence modes of REY in raw coal and 7 density fraction samples were studied.The results show that the content of REY in the raw coal reaches 220.67 μg/g,which is significantly higher than the average REY content in the world coal and Chinese coal as reported in the literature.Gravity separation has a certain pre-enrichment effect on REY and the fraction sample> 1.8 g/cm~3 has the highest REY of 426.27 μg/g(equal to rare earth oxide 0.1%).Study on correlation between REY and ash yields reveals that the organic affinity of the light rare earth is higher than that of the medium rare earth and the heavy rare earth.As shown by X-ray diffraction(XRD) and X-ray flouresence spectroscopy(XRF),the major minerals in coal are kaolinite,quartz and calcite,and the content of REY in coal is significantly related to Al,Si and kaolinite,which implies that REY occur mainly in kaolinite.Laser ablation inductively coupled plasma mass spectroscopy(LA-ICP-MS) was adopted to determine chemical composition of micro-zone in kaolinite in coal and the results show that there is no obvious correlation between REY and the contents of Al and Si.This indicates that the REY occur probably in the form of adsorption.The research results provide a scientific reference for the potential extraction of the associated REY in the coal.

宁东煤田横城矿区太原组煤中关键金属的物质来源和富集机理

对宁东煤田横城矿区太原组9号煤层进行了矿物学和地球化学研究,以便查明煤中关键金属的分布、赋存和富集特征,并评价其综合利用前景。研究结果表明:①横城矿区9号煤以高的镜质组含量、特低—低灰分产率和中—高硫含量为特征。②煤中矿物主要由高岭石组成,以细胞充填状、透镜状和薄层状等形式存在。煤层底板中矿物主要由石英、高岭石和白云母组成,其主要为碎屑成因。③煤层中常量元素主要由SiO_(2)和Al_(2)O_(3)组成,煤中Li、Zr、Nb、Hf、Pb和Th的含量达到轻度富集—富集程度,其中Li、Pb和Th主要赋存于高岭石,Zr和Hf赋存于锆石,Nb赋存于高岭石和锐钛矿。矿区9号煤层形成于受海水影响的潮坪-潟湖环境,煤层下部形成于铁源供给不足的低位沼泽环境,煤层上部形成于铁源严重不足的高位沼泽环境,故下部煤层中硫以黄铁矿硫为主而上部以有机硫为主。煤中碎屑物质主要来源于阴山古陆和阿拉善地块,阴山古陆主要提供了元古宙的陆源碎屑物质,阿拉善地块主要供给了早石炭世的碎屑物质,此外也有少量的火山灰和奥陶系灰岩风化残积物进入到含煤盆地。煤中的Li、Zr、Nb等关键金属的富集主要受控于长英质的碱性—过碱性物质输入量的多少,同时水/岩作用过程也导致了关键金属的活化、迁移和重新分配。煤灰中Li_(2)O含量超过其边界品位,REO、Ga、Zr和REY接近相应边界品位,故可考虑Li-Ga-Zr-REY等的综合开发利用。

西北太平洋公海中上层游泳动物体内必需微量元素赋存特征

中上层游泳动物具有较强的微量元素富集能力,通过食物链的生物放大作用,其体内富集的微量元素会传递到高营养级生物体内。为了解西北太平洋中上层游泳动物肌肉微量元素赋存特征,采集西北太平洋远东拟沙丁鱼(Sardinops sagax)、三棘若蛇鲭(Nealotus tripes)、鳀(Engraulis japonicus)、北方拟黵乌贼(Gonatopsis borealis)、发光柔鱼(Eucleoteuthis luminosa)和日本爪乌贼(Onychoteuthis borealijaponica)等6种中上层游泳动物样品,测定其肌肉中必需微量元素B、Cr、Mn、Fe、Co、Cu、Zn、Se的含量以及碳氮稳定同位素比值,采用聚类分析、皮尔逊相关分析、主成分分析以及营养放大系数(trophic magnification factor,TMF)等方法揭示微量元素赋存的物种差异、元素之间的相关性和来源以及微量元素与营养级相关性与传递规律。结果表明,西北太平洋6种游泳动物体内必需微量元素含量都遵循Fe>Zn>Cu>Mn>Se>Cr>B>Co的规律,鱼类体内Cr、Mn、Fe、Co和Zn含量明显高于头足类;微量元素在中上层游泳动物物种之间的赋存差异明显(P<0.05),Zn和Mn两个微量元素在3种鱼类(远东拟沙丁鱼、三棘若蛇鲭和鳀)中均存在显著正相关关系;鱼类和头足类体内的Zn、Co、B、Cu和Fe主要是摄食获取,而Mn、Cr和Fe主要来源于栖息水体中;西北太平洋6种游泳动物的食物来源存在差异性(δ13C:-26.9‰~-17.8‰),营养级跨度大(1.7~3.7);Cr在西北太食物链存在生物放大效应(TMF>1),B、Co、Fe、Zn和Se在中上层游泳动物食物链存在显著生物减小效应(TMF<1),其浓度随着营养级的升高呈显著下降趋势(P<0.05)。研究结果可为该海域环境治理以及食品安全监管提供科学参考。

孕期补充叶酸及微量元素对孕妇妊娠结局的影响

目的探讨孕期补充叶酸及微量元素对孕妇妊娠结局的影响。方法以254例分娩孕妇作为研究对象,根据孕妇补充叶酸和微量元素情况进行分组,其中132例孕妇在妊娠前和妊娠早期补充叶酸和微量元素作为研究组,妊娠前补充时间超过1个月,妊娠早期补充时间3个月;122例孕妇仅在妊娠早期单一补充叶酸作为对照组,补充时间3个月。比较两组孕妇的分娩方式、妊娠期并发症发生率及新生儿营养状况。结果研究组孕妇妊娠期并发症发生率为6.06%,明显低于对照组的15.57%,差异具有统计学意义(P<0.05);研究组孕妇的顺产率63.64%明显高于对照组的48.36%,剖宫产率12.12%明显低于对照组的30.33%,差异具有统计学意义(P<0.05);助产率组间比较差异无统计学意义(P>0.05);两组新生儿的身高、头围以及胸围比较,差异无统计学意义(P>0.05)。结论妊娠期间规范化补充微量元素和叶酸可以有效减少孕妇妊娠期并发症的发生率,提高顺产率,降低剖宫产率。

Geochemistry of rare earth elements and yttrium in Late Permian coals from the Zhongliangshan coalfield, southwestern China

Rare earth elements and yttrium(REY)in coal deposits are considered promising alternative sources for these resources owing to their increasing global demand.This paper reports the geochemical characteristics of REY in the Late Permian coals from an underground K1a seam section of the Zhongliangshan coalfield in Chongqing,southwestern China.The mineralogy,degree of enrichment,distribution patterns,modes of occurrence,and sediment origin of REY were investigated.Compared with the average of world coals,the concentration of REY in the K1a coals were normal,dominated by light REY(LREY),with less medium and heavy REY(MREY,HREY).The fractionation degree of the MREY and HREY are higher than that of LREY in most K1a coal samples,deduced from the mixed enrichment type of REY,mainly including M-H-type,and a few L-M type and H-type.In addition,the combination of anomalies of Ce,Eu,Gd,and Al_(2)O_(3)/TiO_(2) parameters,the terrigenous materials in the K1a coal were derived from the felsic-intermediate rocks at the top of the Emeishan basalt sequence,and the samples were affected by seawater intrusion during early peat accumulation.Although the minerals primarily consist of kaolinite,illite,pyrite,and small amounts of quartz,calcite and anatase,REY are correlated with ash yield,SiO2,and Al_(2)O_(3),revealing that the REY mainly occur in aluminosilicate minerals,especially kaolinite and illite.Meanwhile,REY positively relate to P_(2)O_(5) and Zr,which may exist in phosphate-containing minerals or zircon.Furthermore,most samples in the K1a coal or ash do not reach the cut-off grade for the beneficial recovery of REY.With the exception of central Guizhou,southwestern Chongqing,and the junction of western Guizhou and northeastern Yunnan,the REY content in coals from southwestern China are high,and its by-products are suitable as potential REY sources.

黄铜矿微量元素对矿床成因类型的指示

金属矿物微量元素对矿床形成过程和成因类型具有重要指示作用,目前对黄铁矿、磁铁矿及闪锌矿研究较多,黄铜矿微量元素特征鲜有报道。根据收集的斑岩型铜矿床(PCD)、岩浆型铜镍硫化物矿床(MSD)、沉积岩型层状铜矿床(SSC)、铁氧化物铜金矿床(IOCG)、喷流沉积型矿床(SEDEX)及火山成因块状硫化物矿床(VMS)铜精矿样品,结合资料,对黄铜矿开展了详细矿相学和LA-ICP-MS微量元素研究,揭示黄铜矿微量元素特征及其与矿床成因类型的关系。黄铜矿中Mn, Co, Ni, Se, Ag, Sn, Pb及Bi质量分数可达1 000×10^(-6)以上,Ga, Ge, Mo, Cd, In, Sb, Te, Au及Tl质量分数可达100×10^(-6)以上,说明黄铜矿是很多微量元素的重要载体。黄铜矿Sb-Tl, In-Sn, Pb-Bi及Mn-Ni呈明显的正相关关系,其中Sb, Tl, In及Sn主要以固溶体的形式赋存于黄铜矿,Pb与Bi以方铅矿包裹体的形式赋存于黄铜矿,Mn, Co, As, Te, Ag及Ni 2种赋存状态均有发育。PCD型和VMS型黄铜矿微量元素变化大,MSD型黄铜矿中Ni质量分数高,In质量分数较低,SSC型黄铜矿Ge质量分数高,Sn质量分数较低。Se在MSD型和VMS型黄铜矿中质量分数较高,在SEDEX型和SSC型黄铜矿中质量分数较低。Ni, In, Sn元素差异主要与不同类型岩浆作用有关,Se元素质量分数差异主要受温度控制,SSC型黄铜矿Ge元素质量分数高可能与成矿温度和赋矿围岩有关。因此,基于上述微量元素特征,Ni-Co和Ni-In图解可区分MSD型和其他类型,Ni-Se图解可区分SEDEX型,SSC型及VMS型,Ge-Sn图解可进一步区分SSC型和SEDEX型,Co/Ni-Ag/Bi图解可区分MSD型和PCD型,Zn-Sn/In在一定程度上可区分IOCG型和其他类型。这些首次系统地提出的图解将为判别矿床成因类型提供新的参考。

ICP-MS/MS直接测定海水中12种痕量金属元素

建立一种采用电感耦合等离子体串联质谱(ICP-MS/MS)直接测定海水中12种元素的分析方法。采用标准加入法及配置超高基体进样系统实现基体匹配,应用ICP-MS/MS的多种分析模式测定海水中钒(V)、铬(Cr)、锰(Mn)、钴(Co)、镍(Ni)、铜(Cu)、锌(Zn)、砷(As)、钼(Mo)、镉(Cd)、铊(Tl)、铅(Pb)12种痕量元素。用该方法测定海水标准参考物质,结果准确。测定实际海水样品,加标回收率为85.0%~108%,相对标准偏差为1.5%~5.4%。12种元素的方法检出限为0.003~0.085μg/L,定量下限为0.012~0.340μg/L。该方法运行成本低,操作便捷,可作为实验室海水元素分析的常规检测方法。

单元件干涉数字全息的光线追迹模型

基于棱镜对的单元件干涉可以获得透射物体的相位信息,即数字全息,具有结构紧凑、干涉条纹稳定、测量精度高等优点。采用光线追迹方法,综合考虑了棱镜对的方位角旋转、斜面偏心等参数,建立了光线追迹等效模型,仿真了数字全息干涉条纹,给出了条纹密度变化及倾斜的解析表达式。针对单模和多模光纤等微结构光学元件,获得了干涉数字全息图,并反演出其折射率分布。搭建了显微成像单元件干涉实验装置,获得了实际测量干涉图样,实验与仿真结果一致,证明了本模型的有效性。