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1.
对Li-(Mg、Zn、Ni)钒酸盐系统在500—800℃的相图研究发现:(Mg、Zn、Ni)V_2O_6和(Mg、Zn、Ni)_2V_2O_7,二个系统中都有两个主要固溶体,一个以NiV_2O_6(或Ni_2V_2O_7)为主结构,另一个在MgV_2O_6-ZnV_2O_6间形成完全连续型,Mg_2V_2O_7-Zn_2V_2O_7间为MgZnV_2O_7结构型。(Mg、Zn、Ni)_3V_2O_8系统中,整个就是一个固溶体,而Li(Mg、Zn、Ni)VO_4系统中,端员组分相互间也形成不同的固溶体。  相似文献   

2.
绿柱石是一种重要的含铍矿物,化学组成为:3BeO·Al_2O_3·6SiO_2,各成份含量的理论值为:BeO14％,Al_2O_319％,SiO_267％,其中部分铍常被钾、钠、锂、钙、铁等金属元素置换。 一般分析项目有:SiO_2、BeO、Al_2O_3、TiO_2、Fe_2O_3、CaO、MgO、Li_2O、K_2O、Na_2O、Rb_2O、Cs_2O、H_2O~±,有时还分析Nb_2O_5、Ta_2O_5。  相似文献   

3.
<正>铁钛氧化物在火成岩和变质岩中广泛存在,不仅具有重要的地磁学意义,还可以作为地质"温度计"和"氧逸度计"反映岩体的形成条件。铁钛氧化物在结晶时主要形成3个系列的固溶体,包括:1)立方晶系"尖晶石型"的磁铁矿(Fe2+Fe3+2O4)—钛铁晶石(Fe2+2Ti O4)固溶体;2)三方晶系"刚玉型"的赤铁矿(Fe2O3)—钛铁矿(Fe Ti O3)固溶体;3)正交晶系的"假板钛矿"系列固溶体Fe3+2Ti O5—Fe2+Ti2O5。人工合成实验证明  相似文献   

4.
每个分子单元中SO_3/SO_3+CO_2的量值小于0.3的天然碳柱石(为钙柱石Ca_4Al_6Si_0O_(24)(CO_3)和钠柱石Na_3Ca_4Al_5Si_7O_(24)(CO_3)的固溶体)是在高温麻粒岩相条件下形成的常见矿物相。与斜长石和方解石共生的这些碳柱石的(实验确定的)化学组成可以用来测定天然麻粒岩的形成温度。钙柱石(Ca_4Al_4Si_0O_4(CO_3))的形成、稳定性和相关性是在2kb和10kb条件下,在H_2O CO_2双相流体存在和缺乏条件下分别确定的。在含有钙长石和方解石的组合中,钙柱石按照下面单变反应(简并的)形成:  相似文献   

5.
在t=1100-1500℃和P=0-2.88GPa条件下,实验确定了与金属Cr平衡的SiO_2-Cr-O及MgO-SiO_2-Cr-O体系中的亚固相相关系。结果显示,在SiO_2-Cr-O体系中,只发现绿铬矿-金属铬-石英(或鳞石英)组合;而在含MgO体系中,出现Mg-Cr~(2+)橄榄石、辉石及尖晶石固溶体。Cr~(3+)在橄榄石和辉石中的含量在可测定限度之下。当X_(Cr~(2+))=[Cr~(2+)/(Mg+Cr~(2+))]>0.2时,辉石的结构由斜方晶系转为单斜晶系;尖晶石的结构由立方变为四方。对实验数据进行热力学模拟,求得Mg-Cr~(2+)在橄榄石,辉石及尖晶石固溶体中的混合参数(W),以及铬橄榄石(Cr_2SiO_4)、铬辉石(Cr_2Si_2O_6)和铬尖晶石(Cr_3O_4)的形成自由能(△G°)与温度的关系。  相似文献   

6.
JS-无机凝胶是江苏省地质矿产测试应用研究所研制的一种新型矿物胶体原料。它主要由硅、镁、锂、铝等元素组成,其化学结构式为[(Mg_(2.67)Li_(0.21)Al_(0.05)Fe_(0.01))Si_(3.98)Al_(0.02))O_(10)(OH,F)_2]Na_(0.18)Li_(0.07)Ca_(0.04),它在水中具有极大的成胶性能,配制成1—5％的水分散液就能形成触变性凝胶。其外观和胶体性能优于美国范德比尔特公司的Veegum-F产品。JS-无机凝胶是具有可膨胀结构、带有一定过剩负层电荷的2∶1型层状  相似文献   

7.
天然水中的 He、H_2、N_2、O_2、CH_4和 CO_2等气体成分具有重要的水文地球化学意义。气相色谱法为快速准确地分析这些气体提供了有力的手段。由于 CO_2的极性较强,在5 A 分子筛柱上发生不可逆吸附,故目前多用程序升温或用两根色谱柱(一根充填5 A 分子筛,另一根充填硅胶或活性碳)来完成上述组分的分离测定。这样对测定精度有一定影响,分析周期也较长,或对仪器要求较高(具有程序升温装置或双柱双检测系统)。我们通过试验,用一根 GDX—105柱对 He、H_2、N_2、CH_4和 CO_2进行一次分离测定,取得了满意的效果。  相似文献   

8.
众所周知,在高岭土中 SiO_2与 Al_2O_3之间的比值是确定高岭石矿物含量的一个重要参数,而 Fe_2O_3与 TiO_2的含量则是评价高岭土质量的重要参数。所以 SiO_2、Al_2O_3、Fe_2O_3、TiO_2是高岭土进行化学成分分析的重要分析项目。大量的分析结果表明,高岭土中的 SiO_2含量增高,Al_2O_3含量则相应降低;而 Fe_2O_3  相似文献   

9.
采用多顶砧高压实验装置研究了Mg2SiO4-MgAl2O4体系在压力为22 GPa,温度为1550～1750℃条件下的相变,并考查了Al2O3在γ相中的固溶度.结果表明,随着体系中MgAl2O4组分含量的增加,相组合发生了变化,依次为γ相+镁铝硅酸盐固溶体+方镁石→镁铝硅酸盐固溶体+方镁石→镁铝硅酸盐固溶体+方镁石+刚玉固溶体;镁铝硅酸盐固溶体具有石榴子石结构,其化学成分随着体系中共存相的改变而有所变化;Al2O3在γ相中的固溶度很低(其重量百分比＜0.8%),因此,在Mg2SiO4-MgAl2O4体系中Al2O3可能对γ相超尖晶石分解转变的压力不会有很大的影响.  相似文献   

10.
采用等温溶解平衡法研究了五元体系Li^ ,K^ //CI^-,B4O7%2-,CO3^2-H2O在298K时相关系和平衡液相物化,性质对组分的溶解度以及密度、折光度、粘度、电导率和pH值进行了测定，并绘制了相关相图，得到5个结晶相区和3个共饱点。该体系没有固溶体和复盐生成，为简单共饱和型体系。  相似文献   

11.
Single crystal Raman spectra of pyrite-type RuS2, RuSe2, OsS2, OsSe2, PtP2, and PtAs2 are presented and discussed with reference to the energies of the X-X stretching modes x-x (A g, F g) and the X2 librations (E, 2Fg). The main results obtained are (i) strong Raman resonance effects, (ii) different sequences for x-x (A g) and (E g), i.e., R_{x_2 } $$ " align="middle" border="0"> for PtP2 and PtAs2 and R_{x_2 } $$ " align="middle" border="0"> for OsS2, owing to the interplay of intraionic and interionic lattice forces, (iii) greater strengths for the intraionic P-P and As-As bonds compared to the S-S and Se-Se bonds, respectively, and (iv) a strong influegnce of the metal ions on the strength of the X-X bonds.This is contribution LXI of a series of papers on lattice vibration spectra  相似文献   

12.
We present data for the concentrations of eleven rare earth elements (La, Ce, Pr, Nd, Sm, Eu, Gd, Dy, Er, Yb, Lu) in eleven international geochemical reference materials obtained by isotope dilution multi-collector inductively coupled plasma-mass spectrometry (MC-ICP-MS). We have analysed both rock powders and synthetic silicate glasses, and the latter provide precise data to support the use of these as reference materials for in situ trace element determination techniques. Our data also provide precise measurements of the abundance of mono-isotopic Pr in both glasses and powders, which allows more accurate constraints on the anomalous redox-related behaviour of Ce during geochemical processes. All materials were analysed in replicate providing data that typically reproduce to better than one percent. Sm/Nd ratios in all these materials also reproduce to better than 0.2% and are accurate to < 0.2% and can thus be used as calibrants for Sm-Nd geochronology. Our analyses agree well with existing data on these reference materials. In particular, for NIST SRM 610, USGS BHVO-2, AGV-1 and AGV-2, our measured REE abundances are typically within < 2% (and mostly 1%) of REE concentrations previously determined by isotope dilution analysis and thermal ionisation mass spectrometry, consistent with the higher degree of precision and accuracy obtained from isotope dilution techniques. Close agreement of results between basaltic glass reference materials USGS BHVO-2G and BCR-2G and the BHVO-2 and BCR-2 powders from which they were created suggests that little fractionation, concentration or dilution of REE contents occurred during glass manufacture.  相似文献   

13.
Different batches of the new US Geological Survey (USGS) reference materials (RMs) BCR-2, BHVO-2, AGV-2, DTS-2 and GSP-2 and the original USGS RMs BCR-1, BHVO-1, AGV-1, DTS-1 and GSP-1 have been analysed by isotope dilution using thermal ionisation mass spectrometry (ID-TIMS) and by multi-ion counting spark source mass spectrometry (MIC-SSMS). The concentrations of K, Rb, Sr, Ba and the rare earth elements were determined with overall analytical uncertainties of better than 1% (ID-TIMS) and 3% (MIC-SSMS). The analyses of different aliquots and batches of BCR-2, BHVO-2, AGV-2 and GSP-2, respectively, agree within 1%, i.e. approximately the analytical uncertainties of the data. This indicates an homogeneous distribution of the trace elements in these RMs. Differences in element concentrations of up to 17% in different aliquots of the depleted RM DTS-2 are outside the analytical uncertainty of our data. They may be attributed to a slightly heterogeneous distribution of trace elements in this dunite sample. Our trace element data for BCR-2, BHVO-2, AGV-2 and GSP-2 agree within about 3% with preliminary reference values published by the USGS. They also agree within 1-6% with those of the original RMs BCR-1, BHVO-1, AGV-1 and GSP-1. Large compositional differences are found between DTS-2 and DTS-1, where the concentrations of K, Rb, Sr and the light REE differ by factors of 2 to 24.  相似文献   

14.
We have measured 87Sr/86Sr and 143 Nd/144 Nd isotope ratios in different batches and aliquots of the new US Geological Survey (USGS) reference materials (RMs) BCR-2, BHVO-2, AGV-2 and GSP-2 and the original USGS RMs BCR-1, BHVO-1, AGV-1 and GSP-1 by thermal ionisation mass spectrometry. In addition, we also analysed the eight Max-Planck-Institut-Dingwell (MPI-DING) reference glasses. Nearly all isotope ratios obtained in the different aliquots and batches agree within uncertainty limits indicating excellent homogeneity of the USGS powders and the MPI-DING glasses. With the exception of GSP-2, the new USGS RMs are also indistinguishable from the ratios found in the original USGS RMs (87Sr/86Sr: 0.704960, 0.704958 (BCR-1, -2), 0.703436, 0.703435 (BHVO-1, -2), 0.703931, 0.703931 (AGV-1, -2); 143 Nd/144 Nd: 0.512629, 0.512633 (BCR-1, -2), 0.512957, 0.512957 (BHVO-1, -2); 0.512758, 0.512755 (AGV-1, -2)). This means that for normalisation purposes in Sr and Nd isotope geochemistry BCR-2, BHVO-2 and AGV-2 can well replace BCR-1, BHVO-1 and AGV-1 respectively.  相似文献   

15.
The National Centre for Compositional Characterisation of Materials (NCCCM) / Bhabha Atomic Research Centre (BARC) and National Aluminium Company Limited (NALCO), India have produced an Indian origin bauxite certified reference material (CRM), referred to as BARC-B1201, certified for major (Al2O3, Fe2O3, SiO2, TiO2, loss on ignition - LOI) and trace contents (V2O5, MnO, Cr2O3, MgO). Characterisation was undertaken by strict adherence to ISO Guides. A method previously developed and validated in our laboratory, using single step bauxite dissolution and subsequent quantitation (of Al2O3, Fe2O3, SiO2, TiO2, V2O5, MnO, Cr2O3 and MgO) by ICP-AES (SSBD ICP-AES) was used for homogeneity studies and an inter-laboratory comparison exercise (ILCE) of the candidate CRM. LOI was determined by thermo-gravimetric analysis. Property values were assigned after an ILCE with participation from seventeen reputed government and private sector laboratories in India. The CRM was certified for nine property values: Al2O3, Fe2O3, SiO2, TiO2, V2O5, MnO, Cr2O3, MgO and LOI, which are traceable to SI units.  相似文献   

16.
《International Geology Review》2012,54(11):1220-1226
  相似文献   

17.
Equilibria for several reactions in the system CaO-Al2O3-SiO2-CO2-H2O have been calculated from the reactions calcite+quartz=wollastonite+CO2 (5) and calcite+Al2SiO5+quartz=anorthite+CO2 (19) and other published experimental studies of equilibria in the systems Al2O3-SiO2-H2O and CaO-Al2O3-SiO2-H2O.The calculations indicate that the reactions laumontite+CO2=calcite+kaolinite+2 quartz+2H2O (1) and laumontite+calcite=prehnite+quartz+3H2O+CO2 (3) in the system CaO-Al2O3-SiO2-CO2-H2O, are in equilibrium with an H2O-CO2 fluid phase having -0.0075 for P fluid=P total=2000 bars.These calculations limit the stability of zeolite assemblages to low p CO2.Using the above reactions as model equilibria, several probelms of p CO2 in low grade metamorphism are discussed. (a) the problem of producing zeolitic minerals from metasedimentary assemblages of carbonate, clay mineral, quartz. (b) the significance of calcite (or aragonite) associated with zeolite (or lawsonite) in low grade metamorphism and hydrothermal alteration. (c) the reaction of zeolites (or lawsonite) with calcite (or aragonite) to produce dense Ca-Al-hydrosilicates (eg. prehnite, zoisite, grossular).  相似文献   

18.
LIOU  J. G. 《Journal of Petrology》1971,12(2):379-411
Hydrothermal investigation of the bulk composition CaO.Al2O3.4SiO2+excessH2O has been conducted using conventional techniques over thetemperature ranges 200–450 °C and 500–6000 barsPfluid. A number of reactions have been studied by employingmineral mixtures consisting of reactants and products in about9: 1 and 1: 9 ratios. The phase relations were deduced fromrelatively long experiments by observing which seeded assemblagedisappeared or decreased markedly in one of the paired run charges. Laumontite was synthesized in the laboratory, probably for thefirst time. Laumontite was grown from seeded wairakite to over99 per cent using a weak NaCl solution. The refractive indicesof the synthetic material are about = 1.504 and = 1.514. Theaverage unit cell dimensions are a0 = 14.761±0.005 Å;b0 = 13.077±0.005 Å; c0 = 7.561±0.003 Å;and ß = 112.02°±0.04°. Within the errorof measurement, the optical properties and cell parameters arein good agreement with those of natural laumontite. The equilibriumdehydration of laumontite involves two reactions: (1) laumontite= wairakite+2H2O, passing through about 230 °C at 0.5 kb,255±5 °C at 1 kb, 282±5 °C at 2 kb, 297±5°C at 3 kb and 325±5 °C at 6 kb; and (2) laumontite= lawsonite+2 quartz+2H2O, taking place at about 210 °Cat 3 kb and 275 °C at 3.2 kb. Above 300 °C, the equilibriumcurve for the solid-solid reaction (3) lawsonite+2 quartz =wairakite passes through 305 °C, 3.4 kb and 390 °C,4.4 kb. Equilibrium has been demonstrated unambiguously forthe above three reactions. The hydrothermal decomposition ofnatural laumontite above its own stability limit appears tobe a very slow process. Combined with previously published equilibria determined hydrothermallyfor wairakite, the phase relations are further investigatedby chemographic analysis interrelating the phases, laumontite,wairakite, lawsonite, anorthite, prehnite+kaolinite, and 2 pumpellyite+kaolinitein the system CaAl2Si2O8-SiO2-H2O. This synthesis allowed theconstruction of a semiquantitative petrogenetic grid applicableto natural parageneses and the delineation of the physical conditionsfor the various low-grade metamorphic facies in low µCO2environments. The similar stratigraphic zonations, consistentlyfound in a variety of environments, are recognized to be a functionof burial depth, geothermal gradient, and mineralogical andchemical composition of the parental rocks. Departures fromthe normal sequences are believed to be due to the combinationsof mineralogical variations, availability of H2O, differencesin the ratio µCO2/µH2O, and the rate of reaction.The possible P-T boundaries for diagenesis, the zeolite facies,the lawsonite-albite facies, the prehnite-pumpellyite facies,and the adjacent metamorphic facies are illustrated diagrammatically.  相似文献   

19.
The measurement of concentrations of volatile species in soil gases has potential for use in geochemical exploration for concealed ore deposits and for monitoring of subsurface contaminants. However, the interpretation of anomalies in surficial gases can be difficult because soil-gas concentrations are dependent on both meteorological and environmental conditions.For this study, concentrations of He, CO2, O2 and N2 and meteorological conditions were monitored for 10–14 months at eight nonmineralized sites in both humid and dry environments. Gases were collected at 0.6–0.7-m depth at seven sites. At one site, gases were collected from 0.3-, 0.6-, 1.2-, and 2.0-m depths; diurnal monitoring studies were conducted at this site also. Rain and snowfall, soil and air temperatures, barometric pressure, and relative humidity were monitored at all the sites. The sand, silt and clay content, and the organic carbon content of surficial soil were measured at each site.Meteorological conditions generally affected He and CO2 concentrations in the same way at all the sites; however, these effects were modified by local environmental conditions. Both seasonal and diurnal concentration changes occurred. The most important seasonal concentration changes were related to rain and snowfall and soil and air temperatures. Seasonal changes tended to be larger then the diurnal changes, but both could be related to the same processes. Local conditions of soil type and organic content affected the amount of pore space and moisture present in the soil and therefore the soil-gas concentrations.  相似文献   

20.
Migration of uranium and arsenic in aquatic environments is often controlled by sorption on minerals present along the water flow path. To investigate the sorption behaviour, batch experiments were conducted for uranium and arsenic as single components and also solutions containing both uranium and arsenic in the presence of SiO2, Al2O3, TiO2 and FeOOH at a pH ranging from 3 to 9. In solutions containing only U(VI) or As(V) with the minerals, the sorption of U(VI) was low at acidic pH range and increases with increasing pH, whereas As(V) showed opposite sorption behaviour to Al2O3, TiO2 and FeOOH from acidic pH range to alkaline condition. For the As(V)–SiO2 system, the sorption was low for almost all pH. Sorption of U(VI) and As(V) on SiO2 and FeOOH is almost similar in solutions containing either U(VI) or As(V) separately, or both together. In the U(VI)–As(V)–Al2O3 system, a significant retardation in uranyl sorption and an enhancement in arsenate sorption on Al2O3 were observed for a wide range of pH. The sorption behaviour of U(VI) and As(V) was changed when Al2O3 was replaced by TiO2, where an increase in sorption was observed for both elements. The sorption behaviour of uranyl and arsenate in the U(VI)–As(V)–TiO2 system gives evidence for the formation of uranyl–arsenate complexes. The change in sorption retardation/enhancement of U(VI) and As(V) could be explained by the formation of uranyl–arsenate complexes or due to the competitive sorption between uranyl and arsenate species.  相似文献   

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