长江中下游地区地下水卤素元素的形成及其分布规律     

曾昭华 《浙江国土资源》1997,(1)

本文以丰富的实际资料，论证了地下水的卤素元素（F、Cl、Br、I）的形成、含量及其分布规律与含水介质成分、上覆岩土性质、地下水退流条件、氧化还原环境、地下水矿化度之间的关系。根据江汉平原东部区和鄱阳湖区地下水中Br、I元素的调查研究结果及它们形成的控制因素与分布规律，结合长江三角洲南部区水文地球化学环境条件分析对比，指出该区是一个形成Br、I矿泉水的有利地区。  相似文献   

电感耦合等离子体发射光谱法同时测定玻璃中铝钙铁钾镁钠钛硫   总被引：2，自引：2，他引：0  

杜米芳 《岩矿测试》2008,27(2):146-148

通过选择分析谱线、处理样品方法和消除干扰因素等实验,建立了电感耦合等离子体发射光谱法同时测定玻璃中的Al2O3、CaO、Fe2O3、K2O、MgO、Na2O、TiO2和SO3的方法,克服了利用常规化学法测定玻璃中各氧化物步骤繁琐、耗时长、工作量大的不足。方法的回收率为95.0%~103.0%,精密度(RSD,n=10)为0.20%~1.72%。方法具有快速、简便、线性范围宽等优点,分析误差满足常规化学分析法的要求。用于钠钙硅玻璃及其制品的分析,结果令人满意。  相似文献   

Anoxic nitrification: Evidence from Humber Estuary sediments (UK)   总被引：3，自引：0，他引：3  

Rebecca Bartlett  Robert J.G. Mortimer  Katherine Morris 《Chemical Geology》2008,250(1-4):29-39

Conventional understanding of the nitrogen cycle in marine sediments has changed in recent years with the discovery of an alternative pathway for ammonia oxidation via the reduction of manganese oxides (during anoxic nitrification). In anoxic sediments, the potential for manganese oxides to serve as oxidant for nitrification may be considerable yet previous work on manganese-rich sediments has suggested anoxic nitrification may not be significant. In this study, the potential for anoxic nitrification in a range of sediment types was investigated. Laboratory incubation of sediment from three sites on the Humber Estuary, a microbially diverse environment, showed anoxic accumulation of nitrate, nitrite and dinitrogen gas, with and without the addition of synthetic manganese oxides. Incubation experiments confirmed anoxic nitrification as microbially mediated, with heat-killed controls yielding negative results. The anoxic nitrification reaction significantly depleted ammonia concentrations, and occurred simultaneously with manganese-, iron- and sulphate reduction, and methanogenesis. Taken in conjunction with other studies, results suggest anoxic nitrification may not only be dependent on total manganese concentrations but on manganese dynamics. Anoxic nitrification may be explained as a non-steady state reaction, dependent on the recent stability of a sediment system. Physical perturbation of sediments may cause the redistribution and/or introduction of manganese oxides and promote anoxic nitrification. The significance and persistence of anoxic nitrification is likely to depend on the frequency and magnitude of sediment perturbation, which explains why the reaction varies so widely across studied sites, and why it may not occur in some manganese-rich sediment.  相似文献   

Effects of irrigation on geochemical processes in a paddy soil and in ground waters in Camargue (France)   总被引：2，自引：0，他引：2  

L. Cary  F. Trolard 《Journal of Geochemical Exploration》2006,88(1-3):177

In waterlogged soils, dynamics of water influence the redox conditions and thus the mobility of elements. Irrigation of rice in Camargue (South eastern France) induces yearly dynamics of water. In order to determine the impact of irrigation on the geochemical properties of ground waters, a continuously in situ record of physico-chemical parameters (pH, Eh, temperature and electric conductivity) is performed during 1 year in an irrigated rice field. Seasonal dynamics show large Eh and pH variations. An annual irrigation cycle generates fast precipitations of Ca–Mg carbonates and Fe oxides between 50 and 110 cm depth when the soil is waterlogged. The dissolution of these minerals is initiated during a year without irrigation.  相似文献   

细菌浸铜技术在紫金山铜矿的应用   总被引：4，自引：0，他引：4  

胡世丽  王观石 《江苏地质》2003,27(1):31-33

介绍了生物浸矿技术在紫金山铜矿的应用及在这一过程中发现的一些问题，并提出了有待进一步解决的一些问题。  相似文献   

钙贝塔石(Calciobetafite)在我国的发现     

张如柏  杜崇良  龙照云 《矿物岩石》2003,23(3):5-8

钙贝塔石发现于四川西昌的霓辉石-钠铁闪石脉中，与之共生的矿物是霓辉石，钠铁闪石，钠长石，铈磷灰石，硅钛铈矿，沥青铀矿，重晶石，方解石和彩钼铅矿等。钙贝塔石呈黑色，黑褐色，具八面体晶形，大小为2mm～8mm，条痕为黑色或黄褐色，油脂到沥青光泽，贝壳状断口。摩氏硬度为6．05～6．44(Hv=570．08kg／mm^2～689．06kg／mm^2)；无解理，比重4．51(扭力天平法测定)，反射率从406nm(13．53％)到659nm(11．87％)。经计算钙贝塔石的化学式为：(Ca，Na，U)2(Nb，Ti)2(0，OH)，。钙贝塔石的强X射线：2．975(10．222)，2．570(5．400)，1．816(9．440)，1．549(8．622)，1．050(6．844)，等轴晶系，α=1．029nm。  相似文献   

灰色系统理论预测大气氮氧化物污染的应用   总被引：11，自引：0，他引：11  

茅均标  石健  刘刚  李继明 《华东地质学院学报》2003,26(1):38-40

根据中国南方某省所辖城市近年来N0x污染指数的测量数据的统计资料，建立了GM(1，1）灰色预测模型，通过预测探讨了大气中氮氧化物指数的变化趋势。所建模型残差仅1．17％，关联系数为0．9067，精度较高，具有较好的可行性和适应性，可以为管理规则提供决策依据。  相似文献   

Reactive Nitrogen Compounds at Spitsbergen in the Norwegian Arctic     

S. Solberg  T. Krognes  F. Stordal  OØ Hov  H. J. Beine  D. A. Jaffe  K. C. Clemitshaw  S. A. Penkett 《Journal of Atmospheric Chemistry》1997,28(1-3):209-225

Simultaneousindependent measurements of NO_y and NO_x(NO_x= NO + NO₂) by high-sensitivitychemiluminescence systems and of PAN (peroxyacetylnitrate) and PPN (peroxypropionyl nitrate) by GC-ECDwere made at Spitsbergen in the Norwegian Arcticduring the first half year of 1994. The average mixingratio of the sum of PAN and PPN (denoted PANs)increased from around 150 pptv in early winter to amaximum of around 500 pptv in late March, whereasepisodic peak values reached 800 pptv. This occurredsimultaneously with a maximum in ozone which increasedto 45–50 ppbv in March–April. The average NO_xmixing ratio was 27 pptv and did not show any cyclethrough the period. The NO_y mixing ratio showeda maximum in late March, while the difference betweenNO_y and PAN decreased during spring. This is anindication of the dominance of PAN in the NO_ybudget in the Arctic, but possible changes in theefficiency of the NO_y converter could alsocontribute to this. Although most PAN in theArctic is believed to be due to long range transport,the observations indicate local loss and formationrates of up to 1–2 pptv h^-1 in April–May.Measurements of carbonyl compounds suggest thatacetaldehyde was the dominant, local precursor ofPAN.Now at 1.  相似文献   

Investigating the Halogen Chemistry From High-Latitude Nighttime Stratospheric Measurements of OClO and NO2     

Emmanuel Damien Rivière  Michel Pirre  Gwenaël Berthet  Jean-Baptiste Renard  Franck Lefèvre 《Journal of Atmospheric Chemistry》2004,48(3):261-282

Two cases of simultaneous nighttime measurements of NO₂ and OClO in the winter polar stratosphere are analyzed in order to test our present knowledge of halogen chemistry in the presence of high amount of NO₂ at low temperature. Comparisons with Lagrangian model calculations using several hypotheses are performed. First simulations, using the admitted constant rates of chemical reaction, strongly underestimate the measured OClO while the NO₂ profiles are correctly reproduced. If uncertainties in actinic fluxes calculations are taken into account, simulation results do not show a significant reduction of the underestimation. A better agreement can be achieved if the formation of unstable isomers of ClONO₂ and of BrONO₂ occurs in the cold conditions of the polar stratosphere. An approximate value of the branching ratios of the channels leading to ClONO₂ and ClOONO, and to BrONO₂ and BrOONO, necessary to reproduce both OClO and NO₂ is given and discussed.  相似文献   

Occurrence of Halogen-rich Phlogopite in Late Cenozoic Volcanic Rocks in the Japanese Arcs     

Akira Imai 《Resource Geology》2004,54(2):153-166

Abstract. Halogen-rich phlogopite occurs in the groundmass of andesite and dacite lavas from Late Tertiary to Quaternary volcanoes associated with native sulfur and limonite deposits (Shiretoko-Iwozan, Hachimantai, Adatara, Omeshidake, Masaki) and hydrothermal ore deposits (Harukayama, Muineyama, Hishikari) in Japan. The F contents of the halogen-rich phlogopite range from 3.6 to 5.7 wt%, corresponding to atomic F/(F+C1+OH) ratios ranging from 0.45 to 0.69. On the other hand, the Cl contents of the halogen-rich phlogopite are around 0.2 wt%. The atomic Mg/(Mg+Fe) ratios range from 0.69 to 0.83.
The fluorine intercept value [IV(F)] defined by Munoz (1984) of the phlogopites ranges from 0.79 to 3.17, and the chlorine intercept value [IV(Cl)] ranges from -7.11 to -7.77. The observed IV(F) of the phlogopites broadly overlap the range of the IV(F) for biotites from porphyry copper deposits. On the other hand, the observed IV(Cl) are significantly lower than the IV(Cl) for biotites from porphyry copper deposits. Whereas the F contents of the phlogopite appear more prominent compared to the Cl contents, the calculation of halogen intercept values revealed that the phlogopites are enriched in Cl with respect to the element distribution effect of Mg-Fe substitution. Since the degree of Cl enrichment of the phlogopite is more significant compared to that of biotite in porphyry copper deposits, the phlogopites are considered to have formed under the condition of significantly high activity of halogens. Hydrothermal ore deposits may be formed in magmatic hydrothermal system associated with volcanoes where halogen-rich phlogopite is formed by hypersaline fluid.  相似文献