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Sample records for analcime

  1. Synthesis of Analcime Crystals and Simultaneous Potassium Extraction from Natrolite Syenite

    Directory of Open Access Journals (Sweden)

    Jian Chen

    2017-01-01

    Full Text Available Analcime single crystals were successfully synthesized from natrolite syenite powder (K2O 10.89% and 92.6% of potassium was extracted simultaneously by means of soda roasting followed by alkali-hydrothermal method. Effects of NaOH concentration, reaction temperature, and holding period on the analcime formation and potassium extraction were investigated systemically. The results indicated that NaOH concentration plays an important role in determining the chemical composition of zeolites and size distribution; by turning the NaOH concentrations, three different pure zeolites (i.e., the phillipsite-Na, the analcime, and the sodalite were prepared. Besides, a higher temperature could accelerate the dissolution of K+ ions and enhance the crystallinity degree of zeolite. The reactions involved in the analcime synthesis can be summarized as follows: sodium aluminum silicate dissolution → precipitation and dissolution of metastable zeolite-P → analcime nucleation → analcime growth. The extraction ratio of K+ is associated with the types of synthesized zeolites, among which analcime is the most effective to promote potassium leaching out from zeolite lattice position. The optimal condition for analcime crystallization and K+ leaching is found to be as follows: 175°C for 4 h in 0.5 mol/L NaOH solution.

  2. Solubility and stability of zeolites in aqueous solution. 1: Analcime, Na-, and K-clinoptilolite

    Energy Technology Data Exchange (ETDEWEB)

    Wilkin, R.T.; Barnes, H.L. [Pennsylvania State Univ., University Park, PA (United States). Ore Deposits Research Section

    1998-07-01

    The solubilities of analcime and clinoptilolite were determined in dilute, weakly alkaline, aqueous solutions below 300 C and at vapor-saturated pressures. Analcimes used in this study were from Mont St. Hilaire, Quebec (an{sub 1}, Si/Al = 2.02) and Wikieup, Arizona (an{sub 2}, Si/Al = 2.55); clinoptilolite samples were from Castle Creek, Idaho (Si/Al = 4.50). The effects of alkali content (Na,K) on clinoptilolite solubility were determined by using cation-exchanged varieties of the Castle Creek material. The logarithm of the equilibrium constants of the solubility-controlling reactions were fit to the function: log K = A + BT + C/T + D log T. At 25 C, log K values for the Mont St. Hilaire analcime, Wikieup analcime, Na-clinoptilolite, and K-clinoptilolite are {minus}16.1, -15.0, -26.5, and {minus}28.1, respectively. These data were combined with the thermodynamic properties of the aqueous species Si(OH){sub 4}, Al(OH){sub 4}{sup {minus}}, Na{sup +}, K{sup +}, and liquid water to determine standard Gibbs free energies of formation as a function of temperature. Values of {Delta}G{sub f}{sup 0} at 25 C and 1 bar for the Mont St. Hilaire analcime and Wikieup analcime are {minus}3,089.2 and {minus}3,044.4 kJ/mol, respectively. The {Delta}G{sub f}{sup 0} values for hydrous Na-clinoptilolite and K-clinoptilolite, respectively, are {minus}6,267.9 and {minus}6,107.4 kJ/mol at 25 C and 1 bar. The solubility data reported here, and results obtained from previous calorimetric studies, indicate that the aluminosilicate frameworks of analcime and clinoptilolite are stabilized by an increase in Al content.

  3. An electrode with Ni(II) loaded analcime zeolite catalyst for the electrooxidation of methanol

    Institute of Scientific and Technical Information of China (English)

    Seyed Naser Azizi; Shahram Ghasemi; Neda Salek Gilani

    2014-01-01

    There is a high overvoltage in the oxidation of methanol in fuel cells, and so modified electrodes are used to decrease it. A modified electrode that used Ni(II) loaded analcime zeolite to catalyze the electrooxidation of methanol in alkaline solution was proposed. Analcime zeolite was synthesized by hydrothermal synthesis, and Ni(II) ions were incorporated into the analcime structure, which was then mixed with carbon paste to prepare modified electrode. The electrocatalytic oxidation of methanol on the surface of the modified electrode in alkaline solution was investigated by cyclic voltammetry and chronoamperometry. The effects of the scan rate of the potential, concentration of methanol, and amount of zeolite were investigated. The rate constant for the catalytic reaction of methanol was 6 × 103 cm3 mol-1 s-1 from measurements using chronoamperometry. The proposed electrode significantly improved the electron transfer rate and decreased the overpotential for methanol oxidation.

  4. Investigation of the mechanism of interaction at the hydrothermal conditions of zeolite – cubic analcime with the Li+, Mg2+, Sr2+ and Fe3+ ions

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    Asta TRAIDARAITĖ

    2013-09-01

    Full Text Available Analcime and clinoptilolite are among the most abundant zeolites in nature. During recent decades natural analcimes and clinoptilolites, also synthetic modified analcimes have been investigated as potential and innovative substances, possible to use for the immobilization of radioactive waste, molecular catalysis and other purposes. However, natural analcimes like many natural rocks are contamined with various impurities (about 30 %, which significally reduces their sorption possibilities and possibilities of their using in such chemical technologies as catalysis, fractioning of hydrocarbons and other. In this article the stability of cubic analcime at the hydrothermal conditions at 180 °C temperature in solutions of various concentrations, containing Li+, Mg2+, Sr2+ and Fe3+ ions has been examined. These processes have big signification for the formation of ion-exchanged analcimes, its sorption properties and also if ions have been immobilized in analcime structure. It has been established, that as result of interaction between cubic analcime and lithium chloride solutions the formation of new compounds: lithium silicate and silinaite occurs. At the same hydrothermal conditions the interaction between cubic analcime and chloride solutions, containing Sr2+, Mg2+ and Fe3+ ions pass without formation of new compounds, and only with interposition of these ions in the structure of cubic analcime. DOI: http://dx.doi.org/10.5755/j01.ms.19.3.1496

  5. Analcite formation in the Agades Region (Niger); Les formations a analcime de la Region d'Agades (Republique du Niger)

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    NONE

    1966-06-01

    A study based mainly upon field mapping and drill cores examination, followed by a laboratory survey allows us to support a genetic hypothesis upon the formation of analcime in the 'Continental intercalaire' of Agades (Niger). Analcime could be generated from an early diagenesis of argillaceous sediments influenced by high soda content fossil waters inside confined continental sedimentary basins. (authors) [French] Une etude axee essentiellement sur des leves de terrain et des carottes de sondages, suivie d'une etude en laboratoire, permet d'avancer une hypothese genetique sur les formations a analcime du Continental Intercalaire d'AGADES (Niger). L'analcime resulterait d'une diagenese precoce de sediments argileux, sous l'influence d'eaux connees riches en soude, dans des bassins sedimentaires continentaux confines.

  6. Kinetic study of the sorption process with Cu(II ions on clinoptilolite and analcime. Effects of temperature and particle size

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    CLAUDIA COBZARU

    2009-05-01

    Full Text Available The sorption process of the Cu(II ions on the clinoptilolite and analcime containing volcanic tuff was studied at different temperatures like 40, 60 and 80 °C. The effects of temperature and a particle size on the sorption capacity of the used zeolites were analysed.

  7. Self-construction of core-shell and hollow zeolite analcime icositetrahedra: a reversed crystal growth process via oriented aggregation of nanocrystallites and recrystallization from surface to core.

    Science.gov (United States)

    Chen, Xueying; Qiao, Minghua; Xie, Songhai; Fan, Kangnian; Zhou, Wuzong; He, Heyong

    2007-10-31

    Zeolite analcime with a core-shell and hollow icositetrahedron architecture was prepared by a one-pot hydrothermal route in the presence of ethylamine and Raney Ni. Detailed investigations on samples at different preparation stages revealed that the growth of the complex single crystalline geometrical structure did not follow the classic crystal growth route, i.e., a crystal with a highly symmetric morphology (such as polyhedra) is normally developed by attachment of atoms or ions to a nucleus. A reversed crystal growth process through oriented aggregation of nanocrystallites and surface recrystallization was observed. The whole process can be described by the following four successive steps. (1) Primary analcime nanoplatelets undergo oriented aggregation to yield discus-shaped particles. (2) These disci further assemble into polycrystalline microspheres. (3) The relatively large platelets grow into nanorods by consuming the smaller ones, and meanwhile, the surface of the microspheres recrystallizes into a thin single crystalline icositetrahedral shell via Ostwald ripening. (4) Recrystallization continues from the surface to the core at the expense of the nanorods, and the thickness of the monocrystalline shell keeps on increasing until all the nanorods are consumed, leading to hollow single crystalline analcime icositetrahedra. The present work adds new useful information for the understanding of the principles of zeolite growth.

  8. Review of the thermal stability and cation exchange properties of the zeolite minerals clinoptilolite, mordenite, and analcime; applications to radioactive waste isolation in silicic tuff

    Energy Technology Data Exchange (ETDEWEB)

    Smyth, J.R.; Caporuscio, F.A.

    1981-06-01

    Silicic tuffs of the southern Great Basin and basalts of the Columbia River Plateau are under investigation as potential host rocks for high- and intermediate-level radioactive wastes. Nonwelded and partially welded tuffs may contain major amounts (> 50%) of the zeolite minerals clinoptilolite, mordenite, and analcime. Densely welded tuffs and some basalt flows may contain clinoptilolite as fracture filling that limits the permeability of these rocks. The cation exchange properties of these zeolite minerals allow them to pose a formidable natural barrier to the migration of cationic species of various radionuclides in aqueous solutions. However, these minerals are unstable at elevated temperatures and at low water-vapor pressures and may break down either by reversible dehydration or by irreversible mineralogical reactions. All the breakdown reactions occurring at increased temperature involve a net volume reduction and evolution of fluids. Thus, they may provide a pathway (shrinkage fractures) and a driving force (fluid pressure) for release of radionuclides to the biosphere. These reactions may be avoided by keeping zeolite-bearing horizons saturated with water and below about 85{sup 0}C. This may restrict allowable gross thermal loadings in waste repositories in volcanic rocks.

  9. Use of analcime zeolite from mineral coal fly ash in adsorption of Cu{sup +2} and Cd{sup +2} in aqueous solutions; Utilizacao de zeolita analcima a partir de cinza leve de carvao mineral na adsorcao de Cu{sup +2} e Cd{sup +2} em soluoes aquosas

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    Rocha Junior, C.A.F.; Santos, S.C.A.; Angelica, R.S.; Neves, R.F.; Souza, C.A.G., E-mail: augustorocha2@gmail.com [Universidade Federal do Para (UFPA), Coqueiro, PA (Brazil)

    2011-07-01

    The use of zeolite for removing heavy metals from contaminated effluents over the years has been widespread due to its high cation exchange capacity in aqueous solutions. Thus this study aims to use analcime zeolite for removal of Cu{sup +2} and Cd{sup +2} from aqueous solutions at different concentrations, and the zeolitic material synthesized from coal fly ash generated in an alumina plant in northern Brazil . The use of zeolite analcime proved quite satisfactory, since this product has removed almost entirely Cu{sup +2} and Cd{sup +2} solutions with concentrations up to 200ppm, and demonstrated an average capacity for solutions of 400ppm, which shows good applicability of this material for the treatment of effluent contamination in the ranges studied. The adsorption models of Langmuir and Freundlich showed a good fit to experimental data generated in this work. (author)

  10. Efeito do glutaraldeído na adsorção de extrato proteico da Ipomoea Batatas (L Lam na superficie de uma zeólita analcima Effect of the glutaraldeide on the adsorption of proteic extract of the Ipomoea Batatas (L Lam in analcime zeolite surface

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    A. C. S. Gondim

    2005-09-01

    Full Text Available A zeólita analcime (Na16Al16Si32O96.nH 2O foi submetida a ataque ácido com HCl 0,25 mol.L-1, seguido da funcionalização com glutaraldeído, foi imersa em extrato protéico obtido da polpa da batata-doce (Ipomoea Batatas (L Lam, que tem em sua composição a enzima polifenol oxidase (PFO. As amostras foram submetidas a procedimentos de caracterização por microscopia eletrônica de varredura, espectroscopia na região do infravermelho com transformada de Fourier e termogravimetria.The analcime zeolite (Na16Al16Si32O96.nH2O was treated with hydrochloric acid 0.25 mol.L-1, followed by the funcionalization with glutaraldehyde and immersed in the proteic extract obtained from gross extract of sweet potato pulp (Ipomoea Batatas (L Lam, which presents in its composition the polyphenol oxidase enzyme (PPO. Other samples were submitted to the same procedure with characterizations by scanning electron microscopy, Fourier Transform Infrared spectroscopy and thermogravimetry.

  11. 方沸石大单晶及多晶粉饼力学性能的实验研究%Experimental Research on Mechanical Properties of Large Zeolite Analcime Single Crystals and Zeolite Powder Bulk

    Institute of Scientific and Technical Information of China (English)

    林江; 牛晓燕; 树学锋

    2005-01-01

    报道了采用纳米压痕硬度计和Instron仪器分别对方沸石ANA大单晶和方沸石ANA多晶粉饼进行的力学性能测试工作.在纳米压痕实验中可实时测得连续载荷和随载荷连续变化而变化的位移,得到载荷-位移曲线图.根据W.C.Olive算法,利用接触刚度连续测量(CSM)技术,实现了ANA沸石的硬度、弹性模量随压痕深度变化的连续测量,得到了ANA沸石单晶的硬度、弹性模量分别为0.25GPa 和4GPa.用Instron仪器测得ANA多晶粉饼的弹性模量值为125MPa.对ANA 沸石大单晶和ANA 沸石多晶粉饼的力学性能进行了比较.

  12. Estimación de propiedades termodinámicas de silicatos. Construcción de diagramas de actividad de zeolitas

    OpenAIRE

    La Iglesia, A.

    1995-01-01

    In this paper we analyze the present methods of estimation of the thermodynamic properties of silicates with special emphasis on the free energy and enthalpy of zeolites. These data are not available in the literature, as these phases are chemically complexo The obtained values allow us to build the 10 following thermodynamic equilibrium diagrams: solubility of laumontite, chabazite, analcime, volcanic glass, zeolite A and zeolite X, and stability diagrams of chabazite-analcime-phillipsite-vo...

  13. Zeolite thermodynamics and kinetics. Final report for June 15, 1996 to June 15, 2000 to the U.S. Department of Energy, Geosciences Research Program, Office of Basic Energy Sciences on Grant No. DE-FG02-96ER14634

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    Barnes, H.L.; Wilkin, R.T.; Benning, L.G.

    2000-06-15

    This report summarizes results obtained on the thermodynamic and kinetic properties of zeolites. DOE funding supported the development of techniques of material preparation as well as experimental strategies and methods for measuring solubilities, hydration states, and rates of zeolite dissolution, precipitation, and nucleation. The hydrothermal experiments provided temperature-dependent solubility products, hydration states, and a set of standard free energies of formation for end-member Na-, K-, and Ca-clinoptilolite, mordenite, and analcime. Flow-through experimental methods were used to measure the rates of Na-clinoptilolite and analcime dissolution and precipitation as a function of reaction affinity to 250C. Finally, the experimental system was modified so that the clinoptilolite-to-analcime transformation was monitored, and its rates and mechanisms were evaluated.

  14. Eudialyte decomposition minerals with new hitherto undescribed phases from the Ilímaussaq complex, South Greenland

    DEFF Research Database (Denmark)

    Karup-Møller, Sven; Rose-Hansen, J.; Sørensen, H.

    2010-01-01

    are distinguished: alteration of eudialyte to catapleiite is widespread in the complex, whereas alteration to zircon only occurs in strongly altered rocks. additionally, the fol-lowing minerals have been identified in the altered eudialyte: aegirine, K-feldspar, albite, analcime, fluorite, monazite, apatite...

  15. Kinetic measurements on the silicates of the Yucca Mountain potential repository. Final report for October 1994--September 1995

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    Barnes, H.L.; Wilkin, R.T. [Pennsylvania State Univ., University Park, PA (United States). Ore Deposits Research Section

    1995-08-01

    This Final Report includes a summary and discussion of results obtained under this project on the solubilities in subcritical aqueous solutions of Mont St. Hilaire analcime, Wikieup analcime, and Castle Creek Na-clinoptilolite. Also included here are the methods and results of hydrothermal flow-through experiments designed to measure the rates of Na-clinoptilolite dissolution and precipitation at 125{degree}C. In this report, high-temperature solubility measurements made in our lab are integrated and discussed along with the low-temperature measurements made at Yale University. The final report prepared by the group at Yale University (Lasaga et al.) includes a synthesis of dissolution rate measurements made between 25{degree} and 125{degree}C on the Na-clinoptilolite.

  16. Oxygen and hydrogen isotope geochemistry of zeolites

    Science.gov (United States)

    Karlsson, Haraldur R.; Clayton, Robert N.

    1990-01-01

    Oxygen and hydrogen isotope ratios for natural samples of the zeolites analcime, chabazite, clinoptilolite, laumontite, mordenite, and natrolite have been obtained. The zeolite samples were classified into sedimentary, hydrothermal, and igneous groups. The ratios for each species of zeolite are reported. The results are used to discuss the origin of channel water, the role of zeolites in water-rock interaction, and the possibility that a calibrated zeolite could be used as a low-temperature geothermometer.

  17. Low-grade Prehnite-Pumpellyite facies metamorphism in the Bamble sector, SE-Norway

    OpenAIRE

    Velo, Mari Roen

    2014-01-01

    Low-grade metamorphic minerals have been found within the high-grade terrain in the Bamble sector, SE-Norway. The minerals prehnite and pumpellyite indicative of prehnite-pumpellyite facies conditions have been confirmed around the Kragerø area. The formation of analcime, thomsonite, hydrogarnet, albite and clay minerals is also a part of the low-grade metamorphism. The occurrence of these low-grade minerals is constricted to pseudomorph replacement of earlier mineral phases, hydrothermal vei...

  18. The Mineralogy and Geochemistry of Manganese Nodules From the Southern Ocean

    Science.gov (United States)

    1968-02-01

    assisted with the preparation of certain segments of this thesis. Mr. Ivar Zemmels performed a number of element tests with the X-ray fluorescence...analcime(?) probably formed during the latter stages of cooling of submarine lava flows. Apatite, calcite and cristobalite (?) can be attri- buted to...standard. Peak areas were calculated by multiplying the base width and peak half-height. Some of the diffractograms were prepared using a mono- chromator

  19. Carbon dioxide capture utilizing zeolites synthesized with paper sludge and scrap-glass.

    Science.gov (United States)

    Espejel-Ayala, F; Corella, R Chora; Pérez, A Morales; Pérez-Hernández, R; Ramírez-Zamora, R M

    2014-12-01

    The present work introduces the study of the CO2 capture process by zeolites synthesized from paper sludge and scrap glass. Zeolites ZSM-5, analcime and wairakite were produced by means of two types of Structure Directing Agents (SDA): tetrapropilamonium (TPA) and ethanol. On the one hand, zeolite ZSM-5 was synthesized using TPA; on the other hand, analcime and wairakite were produced with ethanol. The temperature programmed desorption (TPD) technique was performed for determining the CO2 sorption capacity of these zeolites at two sorption temperatures: 50 and 100 °C. CO2 sorption capacity of zeolite ZSM-5 synthesized at 50 °C was 0.683 mmol/g representing 38.2% of the value measured for a zeolite ZSM-5 commercial. Zeolite analcime showed a higher CO2 sorption capacity (1.698 mmol/g) at 50 °C and its regeneration temperature was relatively low. Zeolites synthesized in this study can be used in the purification of biogas and this will produce energy without increasing the atmospheric CO2 concentrations.

  20. Synthesis of nanosized ZSM-5 zeolite using extracted silica from rice husk without adding any alumina source

    Science.gov (United States)

    Sari, Zahra Ghasemi Laleh Vajheh; Younesi, Habibollah; Kazemian, Hossein

    2015-08-01

    The synthesis of analcime and nanosized ZSM-5 zeolites was carried out by a hydrothermal method with silica extracted from rice husk, available as an inexpensive local biowaste, and without the use of an extra alumina source. Amorphous silica (with 88 wt% of SiO2) was extracted from rice husk ash by a suitable alkali solution. The effects of crystallization temperature, time and SiO2/Al2O3 ratio of the initial system on the properties of final products were investigated. For the characterization of the synthesized product, X-ray diffraction, scanning electron microscope, energy dispersive X-ray techniques, Fourier transform infrared and Brunauer-Emmett-Teller method were applied. Crystallinity percentages of analcime and nanosized ZSM-5 were 95.86 and 89.56, respectively, with specific surface area of 353.5 m2 g-1 for ZSM-5. The experimental results revealed that the synthesis of analcime and nanosized ZSM-5 zeolites was more practical with using silica extracted from inexpensive raw materials, while the whole crystallization process was accomplished without adding any alumina source during.

  1. Effects of alteration product precipitation on glass dissolution

    Energy Technology Data Exchange (ETDEWEB)

    Strachan, Denis M.; Neeway, James J.

    2014-06-01

    Understanding the mechanisms that control the durability of nuclear waste glass is paramount if reliable models are to be constructed so that the glass dissolution rate in a given geological repository can be calculated. Presently, it is agreed that (boro)silicate glasses dissolve in water at a rate dependent on the solution concentration of orthosilicic acid (H4SiO4) with higher [H4SiO4] leading to lower dissolution rates. Once the reaction has slowed as a result of the buildup of H4SiO4, another increase in the rate has been observed that corresponds to the precipitation of certain silica-bearing alteration products. However, it has also been observed that the concentration of silica-bearing solution species does not significantly decrease, indicating saturation, while other glass tracer elements concentrations continue to increase, indicating that the glass is still dissolving. In this study, we have used the Geochemist’s Workbench code to investigate the relationship between glass dissolution rates and the precipitation rate of a representative zeolitic silica-bearing alteration product, analcime [Na(AlSi2O6)∙H2O]. To simplify the calculations, we suppressed all alteration products except analcime, gibbsite (Al(OH)3), and amorphous silica. The pseudo-equilibrium-constant matrix for amorphous silica was substituted for the glass pseudo-equilibrium-constant matrix because it has been shown that silicate glasses act as a silica-only solid with respect to kinetic considerations. In this article, we present the results of our calculations of the glass dissolution rate at different values for the analcime precipitation rate constant and the effects of varying the glass dissolution rate constant at a constant analcime precipitation rate constant. From the simulations we conclude, firstly, that the rate of glass dissolution is dependent on the kinetics of

  2. Geochronology and geochemistry of Eocene-aged volcanic rocks around the Bafra (Samsun, N Turkey) area: Constraints for the interaction of lithospheric mantle and crustal melts

    Science.gov (United States)

    Temizel, İrfan; Arslan, Mehmet; Yücel, Cem; Abdioğlu, Emel; Ruffet, Gilles

    2016-08-01

    40Ar-39Ar age, whole-rock chemical, and Sr-Nd isotope data are presented for the post-collisional, Eocene (51.3-44.1 Ma)-aged volcanic rocks from the Bafra (Samsun) area in the western part of the Eastern Pontides (N Turkey) aiming to unravel their sources and evolutionary history. The studied Eocene volcanic rocks can be divided into two groups: analcime-bearing (tephritic lava flows and dykes) and analcime-free (basaltic to trachytic lava flows and basaltic dykes). The analcime-bearing volcanic rocks have a fine-grained porphyritic texture with clinopyroxene phenocrysts, whereas analcime-free volcanic rocks show a variety of textures including hyalo-microlitic microgranular porphyritic, intersertal, trachytic, fluidal, and glomeroporphyritic. The volcanic rocks also show evidence of mineral-melt disequilibrium textures such as sieved, rounded, and corroded plagioclases, partially melted and dissolved clinopyroxenes and poikilitic texture. Petrochemically, the parental magmas of the volcanic rocks evolved from alkaline to calc-alkaline lava suites and include high-K and shoshonitic compositions. They display enrichments in light rare earth and large ion lithophile elements such as Sr, K, and Rb, as well as depletions in high field strength elements such as Nb, Ta, Zr, and Ti, resembling subduction-related magmas. The analcime-bearing and -free volcanic rocks share similar incompatible element ratios and chondrite-normalised rare rearth element patterns, indicating that they originated from similar sources. They also have relatively low to moderate initial 87Sr/86Sr (0.7042-0.7051), high positive εNd(t) values (+ 0.20 to + 3.32), and depleted mantle Nd model ages (TDM1 = 0.63-0.93 Ga, TDM2 = 0.58-0.84 Ga). The bulk-rock chemical and Sr-Nd isotope features as well as the high Rb/Y and Th/Zr, but low Nb/Zr and Nb/Y ratios, indicate that the volcanic rocks were derived from a lithospheric mantle source that had been metasomatised by slab-derived fluids. Trace element

  3. Hydrothermal zeolitisation controlled by host-rock lithofacies in the Periadriatic (Oligocene) Smrekovec submarine composite stratovolcano, Slovenia

    Science.gov (United States)

    Kralj, Polona

    2016-05-01

    Hydrothermal zeolites (laumontite, yugawaralite, analcime, heulandite, clinoptilolite), prehnite and pumpellyite have been recognised in a succession of volcanic, autoclastic, pyroclastic, resedimented volcaniclastic and mixed siliciclastic-volcaniclastic deposits. In cone-building lithofacies association attaining 310 m, the alteration minerals commonly change within a single normally graded depositional unit or alternate in the section on a dm- to m-scale, according to the host-rock lithofacies. Fine-grained deposits rich in juvenile glassy pyroclasts are altered to heulandite and clinoptilolite or analcime, and laumontite widely occurs in coarse-grained host-rocks (lapilli tuff, hyaloclastite breccia, volcaniclastic breccia, hyaloclastites) and fracture systems. In near-vent lithofacies association attaining 420 m, prehnite-laumontite, laumontite-analcime, and laumontite-heulandite-clinoptilolite zones developed as a result of superimposed thermal regime generated by the emplacement of an over 200 m thick sill. The recognised dependence of alteration on porosity, permeability and fracturing of the host-rock is closely related to hydrological conditions in the stratovolcano-hosted hydrothermal system with convective-advective flow regime. After separation of steam and gases from convecting hydrothermal fluids, denser liquids outflowed intermittently, preferentially through steeply inclined (20-30°) high-permeability layers in the stratovolcano edifice. In low-permeability layers the flow was slow and thermal conditions were mainly attained by conduction. Zeolites developed only in coarse- and fine-grained vitroclastic tuffs, presumably by the dissolution of volcanic glass. The interstratified siliciclastic siltstones, tuffites and resedimented deposits with low content of glassy particles are devoid of zeolites and indicate compositional constraint on zeolitisation. Lava flows, cooling in a submarine environment and undergoing disintegration and mingling with

  4. Waste Minimization Protocols for the Process of Synthesizing Zeolites from South African Coal Fly Ash

    Directory of Open Access Journals (Sweden)

    Leslie F. Petrik

    2013-04-01

    Full Text Available Production of a high value zeolite from fly ash has been shown to be an avenue for the utilization of South African fly ash which presently constitutes a huge disposal problem. The synthesis of zeolites Na-P1 and analcime on a micro-scale has been successful and preliminary investigation shows that scale-up synthesis is promising. However, the post-synthesis supernatant waste generated contains high levels of NaOH that may constitute a secondary disposal problem. A waste minimization protocol was developed to reduce the volume of waste generated with a view to enhancing the feasibility of the scale synthesis. Series of experiments were conducted in 100 mL jacketed batch reactors. Fly ash was reacted with 5 Mol NaOH on a 1:1 mass basis during the aging step, followed by hydrothermal treatment in which ultrapure water was added to the slurry. This study shows that by re-introducing the supernatant waste into the experiments in such a way that it supplies the required reagent (NaOH for the zeolite synthesis, zeolite Na-P1 and analcime can be synthesized. It also shows that the synthesis process can be altered to allow up to 100% re-use of the supernatant waste to yield high value zeolitic products. This study effectively constructed two protocols for the minimization of waste generated during the synthesis of zeolites from South African coal fly ash. This result could be used to establish a basis for legal and environmental aspects involved in the commission of a full-scale plant synthesizing zeolites NaP1 and analcime.

  5. Synthesis of zeolites using fly ash and their application in removing heavy metals from waters

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Three types of zeolite (NaP1 zeolite, analcime and chabazite) were hydrothermally synthesized by reacting fly ash with NaOH solution. The maximum conversion rate from fly ash to single zeolite is about 40%-75%, and the total conversion rate 60%-80%. The synthesis experimental results indicate that factors including vortex, viscosity, temperature, reaction time, and NaOH concentration in the reaction system strongly affect the type and conversion rate of zeolites. The batch experiments of removing Cu2+, Pb2+ and Cd2+ from wastewaters show that the adsorption capacity of zeolites synthesized is higher than that of fly ash.

  6. Synthesis of zeolitic materials from volcanic ash in presence and absence of cetyltrimethylammonium bromide

    Energy Technology Data Exchange (ETDEWEB)

    Sanhueza N, V. M.; Bennun T, L. D., E-mail: vsanhuez@udec.cl [Universidad de Concepcion, Facultad de Ciencias Quimicas, Edmundo Larenas 129, Region del Biobio (Chile)

    2015-07-01

    Zeolitic materials as Na-phillipsite, Na-K-phillipsite-like zeolites and the mixtures of zeolites (phillipsite+analcime and phillipsite+chabazite+analcime) were synthesized from volcanic ash, either in presence and absence of cetiltrimetilamonium bromide (CTAB). The ash sample used in the laboratory experiments contains 75.36% SiO{sub 2} and 14.11% Al{sub 2}O{sub 3}, abundances. The reaction time as well as the influence of CTAB were studied in the zeolitic materials crystallization. The experiments were carried out under hydrothermal conditions, autogenic pressure and temperature of 150 grades C, as well as reaction time from 8 to 116 h. Products from this hydrothermal treatment were identified by X-ray diffraction (XRD) and characterized by scanning electron microscopy-energy dispersive X-ray spectroscopy (Sem-EDS). Of the zeolitic materials obtained the Na-K-phillipsite-like zeolite was found to be the most effective for the retention of cations Pb{sup 2+}, Zn{sup 2+} and Ba{sup 2+}. (Author)

  7. Diagenesis of Oligocene continental sandstones in salt-walled mini-basins-Sivas Basin, Turkey

    Science.gov (United States)

    Pichat, Alexandre; Hoareau, Guilhem; Callot, Jean-Paul; Ringenbach, Jean-Claude

    2016-06-01

    The recent discovery of Oligo-Miocene salt-walled continental mini-basins in the Sivas Basin (central Anatolia, Turkey) provides the opportunity to unravel the influence of halokinesis on the diagenesis of continental mini-basin infilling. In this study, petrographic and geochemical analyses are used to define the diagenetic sequences recorded by two mini-basins filled mainly by fluvial clastic sediments of the upper Oligocene Karayün Formation. The initial diagenetic features are those commonly encountered in arid to semi-arid continental environments, i.e. clay infiltration, hematite precipitation and vadose calcite cement. Other early cements were strongly controlled by sandstone detrital composition in the presence of saline/alkaline pore water. In feldspathic litharenites and lithic arkoses, near-surface alterations were characterized by the precipitation of analcime (up to 10%), albite and quartz overgrowths (burial diagenesis which prevented further mesogenetic alteration phenomena such as compaction. In feldsarenites, early diagenesis differs by (i) the absence of analcime, (ii) better developed albite cements, (iii) thin smectite-illite coatings forming pore linings and (iv) patchy calcite cementation (burial, and result in a significant degradation of porosity.

  8. Clay mineralogy of the Boda Claystone Formation (Mecsek Mts., SW Hungary

    Directory of Open Access Journals (Sweden)

    Németh Tibor

    2016-04-01

    Full Text Available Boda Claystone Formation (BCF is the host rock of the planned site for high level nuclear waste repository inHungary. Samples representing the dominant rock types of BCF were studied: albitic claystone, claystone with high illite content, and analcime bearing claystone. Clay minerals in these three rock types were characterized by Xray powder diffraction (XRD, transmission electron microscopy (TEM and thermal analysis (DTA-TG, and the results were discussed from the point of view of the radionuclide sorption properties being studied in the future. Mineral compositions of bulk BCF samples vary in wide ranges. In the albitic sample, besides the dominant illite, few percent of chlorite represents the layer silicates in the clay fraction. Illite is the dominating phase in the illitic sample, with a few percent of chlorite. HRTEM study revealed that the thickness of illite particles rarely reaches 10 layers, usually are of 5-6 TOT layer thick. Illite crystals are generally thicker in the albitic sample than in the illitic one. The significant difference between the clay mineral characterisitics of the analcimous and the other two samples is that the former contains regularly interstratified chlorite/smectite beside the dominant illite.

  9. Diagramas de eslabilidad de zeolitas. I. Zeolitas en ambientes confinados alcalinos

    Directory of Open Access Journals (Sweden)

    La Iglesia, A.

    1989-12-01

    Full Text Available The stability fieds of zeolites in saline alkaline-lake deposits has been studied. Thermodynamical equilibriums were calculed by ussing a method of stimating the Gibbs free energies of formation of zeolites. We have studied the following stability fields: - Diagram c1inoptilolite-erionite-phillipsite.- Diagram analcime-clinoptilolite-chabazite-erionite-mordenite-phillipsite.- Diagram K-feldspar-zeolites in saline alkaline-lake deposits.The obtained stability diagrams show the influence of silica activity, water activity and alkaline ions activity on equilibrium relationship between analcime and alkalic silicic zeolites, and or feldspar and zeolites. pH influence on the solubility zeolites has been also studied. These results show, at pH below 10, that the most silicic zeolites (clinoptilolite and mordenite are more stable than low silicic ones (analcime and chabazite. However, at pH above 10, the low silicic zeolites are the most stable phases.Se estudia la estabilidad de las zeolitas que aparecen en ambientes confinados salinos. Los cálculos de equilibrio se realizan usando valores de energía libre de Gibbs estimados teóricamente. En este artículo se presentan los siguientes diagramas de estabilidad:- Diagrama clinoptiloita-erionita-phillipsita.- Diagrama aoalcima-clinoptilolita-chabazita-eriooita-mordenita-phillipsita.- Diagrama feldespato potásico-zeolitas depósitos salinos.Los diagramas calculados ponen de manifiesto la influencia de las actividades de los iones alcalinos, alcalinotérreos, agua y sílice en el equilibrio entre las distintas zeolitas y entre estas y el feldespato potásico. Se estudia también la influencia del pH en la solubilidad de las zeolitas. Los resultados obtenidos demuestran que las zeolitas muy silícicas (clinoptilolita y mordenita son las más estables a pH inferiores a 10. Por el contrario, las zeolitas de bajo contenido en sílice (analcima y chabazita son las más estables a pH superiores a 10.

  10. Mineral Chemistry and Precipitation Kinetics of Dawsonite in the Geological Sequestration of CO2

    Science.gov (United States)

    Duan, R.; Carey, J. W.; Kaszuba, J. P.

    2005-12-01

    Dawsonite [NaAl(OH)2CO3] is a relatively rare mineral that may play an important role in the geological sequestration of CO2: thermodynamic and reactive transport calculations predict that dawsonite should precipitate under a variety of CO2 injection scenarios by dissolution of Al-bearing minerals in Na-bearing brine. The precipitation of dawsonite is potentially beneficial as a means of fixing the CO2 in solid form but could also modify porosity and permeability. The relative rarity of natural dawsonite occurrences, however, indicates that either appropriate CO2-rich environments are rare in nature or that dawsonite formation is inhibited or more complex than the simplified geochemical systems used in the model calculations. We have conducted synthesis experiments and dissolution studies to help understand precipitation dynamics, Na-K substitution, and solubility. Both Na- and K-dawsonite were readily synthesized from mixtures of (Na,K)HCO3 and gibbsite [Al(OH)3] at 150°C for 24 hours. [Syntheses were made in unstirred, closed ParrTM reaction vessels and consisted generally of 15 ml of H2O with 6 g (Na,K)HCO3 and sufficient Al-bearing mineral to achieve a (Na,K)/Al ratio of 8.] At lower temperatures, a 41% yield of dawsonite was achieved at 120°C; 1% at 94°C; and no reaction was observed at ≤75°C. In contrast, other Al-bearing minerals including albite, analcime and pyrophyllite at 150°C (28 days) and albite, pyrophyllite, and clinoptilolite at 200°C (66 days) showed no evidence of dawsonite formation but did yield analcime. Kaolinite, however, did produce 1% dawsonite at 75°C (40 days), 37% at 150°C (90 days), and some dawsonite in addition to a complex mixture of albite, cancrisilite, and other phases at 200°C (66 days). Thermodynamic calculations suggest that silica activity restricts the range of dawsonite stability and synthesis experiments with gibbsite-quartz and gibbsite-opal-CT were significantly different than gibbsite alone. At 150°C, the

  11. Dacite – siltstone peperite from Trlično at Rogatec, Eastern Slovenia

    Directory of Open Access Journals (Sweden)

    Polona Kralj

    2006-06-01

    Full Text Available Dacitic glassy lava flow at Trlično is surrounded by a dacite – siltstone peperite and peperitic breccia that underwent alteration, recognised in two, only a few metres thick zones. In the higher-temperature alteration zone, albite extensively replaces volcanic glass and primary plagioclases. The siltstone components are altered to microcrystalline quartz, iron oxides and interlayered illite/smectite clay minerals. This zone developed upon thermalmetamorphosis related to the transfer of heat from the cooling lava. In the lower temperature alteration zone, analcime occurs as the replacement of volcanic glass and pore- and fissure-filling, while the primary plagioclases and poorly lithified siltstone remained fairly unchanged. This zone developed under hydrothermal conditions related to the heating, circulation and reactions of pore waters in the sediment surrounding the lava flow.

  12. Inorganic Corrosion-Inhibitive Pigments for High-Temperature Alkali-activated Well Casing Foam Cement

    Energy Technology Data Exchange (ETDEWEB)

    Sugama, T. [Brookhaven National Lab. (BNL), Upton, NY (United States); Pyatina, T. [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2014-11-14

    This study evaluates inorganic pigments for improving carbon steel (CS) brine-corrosion protection by the sodium metasilicate-activated calcium aluminate cement/Fly Ash blend at 300°C. Calcium borosilicate (CBS) and zinc phosphate, significantly improved CS corrosion-protection by decreasing cement’s permeability for corrosive ions and inhibiting anodic corrosion. An amorphous Na2O-Al2O3-SiO2-H2O phase tightly attached to CS surface formed at 300oC in CBS-modified cement pore solution. The corrosion rate of the CS covered with this phase was nearly 4-fold lower than in the case of nonmodified cement pore solution where the major phase formed on the surface of CS was crystalline analcime.

  13. Inorganic Corrosion-Inhibitive Pigments for High-Temperature Alkali-activated Well Casing Foam Cement

    Energy Technology Data Exchange (ETDEWEB)

    Sugama, T. [Brookhaven National Lab. (BNL), Upton, NY (United States); Pyatina, T. [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2014-11-01

    This study evaluates inorganic pigments for improving carbon steel (CS) brine-corrosion protection by the sodium metasilicate-activated calcium aluminate cement/Fly Ash blend at 300°C. Calcium borosilicate (CBS) and zinc phosphate, significantly improved CS corrosion-protection by decreasing cement’s permeability for corrosive ions and inhibiting anodic corrosion. An amorphous Na2O-Al2O3-SiO2-H2O phase tightly attached to CS surface formed at 300oC in CBS-modified cement pore solution. The corrosion rate of the CS covered with this phase was nearly 4-fold lower than in the case of nonmodified cement pore solution where the major phase formed on the surface of CS was crystalline analcime.

  14. Sandwich structure formation mechanism of metakaolin-based geopolymers in the hydrothermal process%地质聚合物水热过程中夹心结构形成机理研究

    Institute of Scientific and Technical Information of China (English)

    徐梦雪; 王艺频; 唐青; 贺艳; 崔学民

    2016-01-01

    利用偏高岭土为原料,以改性水玻璃溶液(摩尔比SiO2/Na2 O=1.0)为碱激发剂,按照产物中Si/Al=1.5(摩尔比)制备地质聚合物,60℃下养护3 d后脱模,在198℃下原位水热反应3.5 h得到由方沸石和地质聚合物组成的夹心型物质。利用X射线衍射( XRD)、扫描电镜( SEM)、N2吸附( BET)等手段对材料进行表征发现,质地均匀的地质聚合物膜片在进行水热反应后内部出现了分层现象,膜片内层的结构疏松,主要是方沸石,外层较为致密,仍为地质聚合物。推测夹心结构的形成机理如下:在水热过程中,外层的地质聚合物膜片中的游离钠离子以及其他养分溶解到水热母液当中,导致在膜片外层达不到晶体成核要求,而在内层可以形成晶核,当晶化条件达到后即可形成方沸石。%Geopolymer gels were prepared according to the designed composition ( Si/Al=1. 5 ) using metakaolin as raw materials and modified water glass (molar ratio of SiO2/Na2O=1. 0) as al-kali activator. Then the geopolymer gels were cured at 60 ℃ for 3 days to form the geopolymer. Through in-situ hydrothermal processing at 198 ℃ for 3. 5 h, a sandwich structure with geopolymers and zeolites was obtained. The analysis of XRD, SEM and BET were used for the characterization of the resulting product. The results indicated that the homogenous geopolymer membrane came to stratification. The sandwich layer was loose and mainly contained analcime. The parcel layer was dense and still composed of amorphous geopolymer. The formation mechanism of sandwich structure was presumed as follow:during the hydrothermal processing, Na+in the parcel layer diffused to the mother liquid, this indicated that there was no condition for the generation of analcime crystal, as a result, the analcime crystal core formed in the inner layer and grew into analcime crystal under suit-able conditions.

  15. The zeolite deposits of Greece

    Science.gov (United States)

    Stamatakis, M.G.; Hall, A.; Hein, J.R.

    1996-01-01

    Zeolites are present in altered pyroclastic rocks at many localities in Greece, and large deposits of potential economic interest are present in three areas: (1) the Evros region of the province of Thrace in the north-eastern part of the Greek mainland; (2) the islands of Kimolos and Poliegos in the western Aegean; and (3) the island of Samos in the eastern Aegean Sea. The deposits in Thrace are of Eocene-Oligocene age and are rich in heulandite and/or clinoptilolite. Those of Kimolos and Poliegos are mainly Quaternary and are rich in mordenite. Those of Samos are Miocene, and are rich in clinoptilolite and/or analcime. The deposits in Thrace are believed to have formed in an open hydrological system by the action of meteoric water, and those of the western Aegean islands in a similar way but under conditions of high heat flow, whereas the deposits in Samos were formed in a saline-alkaline lake.

  16. From anorthite to vesuvianite: an excursion through the minerals first discovered in Italy

    Institute of Scientific and Technical Information of China (English)

    GiovanniFerraris; MarcoCiriotti

    2003-01-01

    With regard to the number of mineral species first dis-covered in a particular country, Italy ranks fourth, being preceded only by USA, Russia and Germany. Important rock-forming minerals like analcime, anorthite, anortho-clase, antigorite, celadonite, diopside, dolomite,forsterite, humite, leucite, lime, lizardite, magnesiochlo-ritoid, magnesite, nepheline, and sepiolite are among the 240 species first discovered in Italy. Other significant first Italian findings are some important index mineralsof the UHP metamorphism (ellenbergerite, phosphoel-lenbergerite, magnesiodumortierite, and magnesiostau-rolite; second occurrence of coesite) which were discov-ered in the well-known and first reported UHP outcrop of the Dora-Màira massif Italy is also the native land of about 30 zeolites and of the two most abundant modern species: balangeroite and carlosturanite, which are rock-forming asbestos-like minerals of serpentinites in the western Alps.

  17. Preliminary stratigraphic and petrologic characterization of core samples from USW-G1, Yucca Mountain, Nevada

    Energy Technology Data Exchange (ETDEWEB)

    Waters, A.C.; Carroll, P.R. (eds.)

    1981-11-01

    Tuffs of the Nevada Test Site are currently under investigation to determine their potential for long-term storage of radioactive waste. As part of this program, hole USW-G1 was drilled to a depth of 6000 ft below the surface, in the central part of the Yucca Mountain area, Nevada Test Site, Nevada. Petrographic study of the USW-G1 core is presented in this report and shows the tuffs (which generally were variably welded ash flows) are partly recrystallized to a variety of secondary minerals. The important alteration products are zeolites (heulandite, clinoptilolite, mordenite and analcime), smectite clays with minor interstratified illite, albite, micas, potassium feldspar, and various forms of silica. Iijima`s zeolite zones I through IV of burial metamorphism can be recognized in the core. Zeolites are first observed at about the 1300-ft depth, and the high-temperature boundary of zeolite stability in this core occurs at about 4350 ft. Analcime persists, either metastably or as a retrograde mineral, deeper in the core. The oxidation state of Fe-Ti oxide minerals, through most of the core, increases as the degree of welding decreases, but towards the bottom of the hole, reducing conditions generally prevail. Four stratigraphic units transected by the core may be potentially favorable sites for a waste repository. These four units, in order of increasing depth in the core, are (1) the lower cooling unit of the Topopah Spring Member, (2) cooling unit II of the Bullfrog Member, (3) the upper part of the Tram tuff, and (4) the Lithic-rich tuff.

  18. Clay mineralogy of the Boda Claystone Formation (Mecsek Mts., SW Hungary)

    Science.gov (United States)

    Németh, Tibor; Máthé, Zoltán; Pekker, Péter; Dódony, István; Kovács-Kis, Viktória; Sipos, Péter; Cora, Ildikó; Kovács, Ivett

    2016-04-01

    Boda Claystone Formation (BCF) is the host rock of the planned site for high level nuclear waste repository inHungary. Samples representing the dominant rock types of BCF were studied: albitic claystone, claystone with high illite content, and analcime bearing claystone. Clay minerals in these three rock types were characterized by Xray powder diffraction (XRD), transmission electron microscopy (TEM) and thermal analysis (DTA-TG), and the results were discussed from the point of view of the radionuclide sorption properties being studied in the future. Mineral compositions of bulk BCF samples vary in wide ranges. In the albitic sample, besides the dominant illite, few percent of chlorite represents the layer silicates in the clay fraction. Illite is the dominating phase in the illitic sample, with a few percent of chlorite. HRTEM study revealed that the thickness of illite particles rarely reaches 10 layers, usually are of 5-6 TOT layer thick. Illite crystals are generally thicker in the albitic sample than in the illitic one. The significant difference between the clay mineral characterisitics of the analcimous and the other two samples is that the former contains regularly interstratified chlorite/smectite beside the dominant illite. Based on the structural and chemical data two illite type minerals are present in the BCF samples: 1M polytype containing octahedral Fe and Mg besides Al, 2M polytype illite generally is free of Fe andMg. Close association of very thin illite plates and nanosized hematite crystals is typical textural feature for BCF. The goal of this study is to provide solid mineralogical basis for further studies focusing on radionuclide sorption properties.

  19. Estimación de propiedades termodinámicas de silicatos. Construcción de diagramas de actividad de zeolitas

    Directory of Open Access Journals (Sweden)

    La Iglesia, A.

    1995-12-01

    Full Text Available In this paper we analyze the present methods of estimation of the thermodynamic properties of silicates with special emphasis on the free energy and enthalpy of zeolites. These data are not available in the literature, as these phases are chemically complexo The obtained values allow us to build the 10 following thermodynamic equilibrium diagrams: solubility of laumontite, chabazite, analcime, volcanic glass, zeolite A and zeolite X, and stability diagrams of chabazite-analcime-phillipsite-volcanic glass, clinoptilolite-phillipsite-erionite, prehnite-laumontite-heulandite, and kaolinite-metakaolinhidrosodalite-zeolite A. These diagrams can be useful to understand the genesis of these minerals and the processes that allow their formation in the laboratory.En este artículo se pasa revista a los métodos actuales de estimación de propiedades termodinámicas de silicatos, haciendo especial énfasis a los dedicados a la estimación de la energía libre de formación y de la entalpía de zeolitas, datos poco disponibles en la bibliografía debido a la complejidad química de estas fases. Los valores obtenidos han permitido construir los 10 diagramas de equilibrio termodinámico siguientes: diagramas de solubilidad de laumontita, chabazita, analcima, vidrio volcánico, zeolita A y zeolita X y los de estabilidad de chabazita-analcima-philipsitavidrio volcánico, clinoptilolita-philipsita-erionita, prehnita-laumontita-heulandita y caolinita-metacaolinita-hidrosodalita-zeolita A. Estos diagramas pueden explicar la génesis de los minerales o los procesos que dan lugar a su síntesis en el laboratorio.

  20. Spatial and stratigraphic distribution of water in oil shale of the Green River Formation using Fischer assay, Piceance Basin, northwestern Colorado

    Science.gov (United States)

    Johnson, Ronald C.; Mercier, Tracey J.; Brownfield, Michael E.

    2014-01-01

    The spatial and stratigraphic distribution of water in oil shale of the Eocene Green River Formation in the Piceance Basin of northwestern Colorado was studied in detail using some 321,000 Fischer assay analyses in the U.S. Geological Survey oil-shale database. The oil-shale section was subdivided into 17 roughly time-stratigraphic intervals, and the distribution of water in each interval was assessed separately. This study was conducted in part to determine whether water produced during retorting of oil shale could provide a significant amount of the water needed for an oil-shale industry. Recent estimates of water requirements vary from 1 to 10 barrels of water per barrel of oil produced, depending on the type of retort process used. Sources of water in Green River oil shale include (1) free water within clay minerals; (2) water from the hydrated minerals nahcolite (NaHCO3), dawsonite (NaAl(OH)2CO3), and analcime (NaAlSi2O6.H20); and (3) minor water produced from the breakdown of organic matter in oil shale during retorting. The amounts represented by each of these sources vary both stratigraphically and areally within the basin. Clay is the most important source of water in the lower part of the oil-shale interval and in many basin-margin areas. Nahcolite and dawsonite are the dominant sources of water in the oil-shale and saline-mineral depocenter, and analcime is important in the upper part of the formation. Organic matter does not appear to be a major source of water. The ratio of water to oil generated with retorting is significantly less than 1:1 for most areas of the basin and for most stratigraphic intervals; thus water within oil shale can provide only a fraction of the water needed for an oil-shale industry.

  1. Preparation for kinetic measurements on the silicates of the Yucca Mountain potential repository. [Final report], June 15, 1993--September 30, 1993

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1993-12-31

    Part 1, ``The Preparation of Clinoptilolite, Mordenite and Analcime,`` summarized progress made during the contract period on preparing Na-end member clinoptilolite, mordenite, and analcime. The objective is to use the prepared zeolites to determine rates of dissolution and precipitation in laboratory flow-through systems in both this lab to 350 C and by the geochemists at Yale University to about 80 C. Because clinoptilolite represents the most complicated phase of these three zeolites and it is most abundant at Yucca Mountain, the authors have concentrated most of their efforts on its preparation. They have collected, high-concentration natural clinoptilolite samples. A hindered settling technique that takes advantage of the relatively low specific gravity of clinoptilolite coupled with ultrasonic cleaning in deionized water has been employed. This material is now a mixed Na-K zeolite which must then be converted to the pure Na-end member composition. In Part 2, ``Draft Manuscript on the Heterogeneous Kinetics of Cristobalite,`` experiments on the rates of reactions of dissolution and precipitation of cristobalite were carried at 150--300 C. Results show that cristobalite may precipitate from hydrothermal solution if the concentration of Si(OH){sub 4} exceeds that at quartz saturation and is less than that of amorphous silica saturation and if there are cristobalite nuclei present. Such nuclei may occur where there has been devitrification of volcanic glasses, for example. Cristobalite has refused to crystallize in the absence of such nuclei. Steady state concentrations were reached experimentally after starting at 150 {degree} with initially supersaturated solutions and at 200 C starting with either supersaturated or undersaturated solutions. From the steady state conditions, equilibrium constants can be derived.

  2. Chemical, mineralogical and molecular biological characterization of the rocks and fluids from a natural gas storage deep reservoir as a baseline for the effects of geological hydrogen storage

    Science.gov (United States)

    Morozova, Daria; Kasina, Monika; Weigt, Jennifer; Merten, Dirk; Pudlo, Dieter; Würdemann, Hilke

    2014-05-01

    Planned transition to renewable energy production from nuclear and CO2-emitting power generation brings the necessity for large scale energy storage capacities. One possibility to store excessive energy produced is to transfer it to chemical forms like hydrogen which can be subsequently injected and stored in subsurface porous rock formations like depleted gas reservoirs and presently used gas storage sites. In order to investigate the feasibility of the hydrogen storage in the subsurface, the collaborative project H2STORE ("hydrogen to store") was initiated. In the scope of this project, potential reactions between microorganism, fluids and rocks induced by hydrogen injection are studied. For the long-term experiments, fluids of natural gas storage are incubated together with rock cores in the high pressure vessels under 40 bar pressure and 40° C temperature with an atmosphere containing 5.8% He as a tracer gas, 3.9% H2 and 90.3% N2. The reservoir is located at a depth of about 2 000 m, and is characterized by a salinity of 88.9 g l-1 NaCl and a temperature of 80° C and therefore represents an extreme environment for microbial life. First geochemical analyses showed a relatively high TOC content of the fluids (about 120 mg l-1) that were also rich in sodium, potassium, calcium, magnesium and iron. Remarkable amounts of heavy metals like zinc and strontium were also detected. XRD analyses of the reservoir sandstones revealed the major components: quartz, plagioclase, K-feldspar, anhydrite and analcime. The sandstones were intercalated by mudstones, consisting of quartz, plagioclase, K-feldspar, analcime, chlorite, mica and carbonates. Genetic profiling of amplified 16S rRNA genes was applied to characterize the microbial community composition by PCR-SSCP (PCR-Single-Strand-Conformation Polymorphism) and DGGE (Denaturing Gradient Gel Electrophoresis). First results indicate the presence of microorganisms belonging to the phylotypes alfa-, beta- and gamma

  3. Origin of sapphires from a lamprophyre dike at Yogo Gulch, Montana, USA: Clues from their melt inclusions

    Science.gov (United States)

    Palke, Aaron C.; Renfro, Nathan D.; Berg, Richard B.

    2016-09-01

    Gem corundum (sapphire) has been mined from an ultramafic lamprophyre dike at Yogo Gulch in central Montana for over 100 years. The sapphires bear signs of corrosion showing that they were not in equilibrium with the lamprophyre that transported them; however, their genesis is poorly understood. We report here the observation of minute glassy melt inclusions in Yogo sapphires. These inclusions are Na- and Ca-rich, Fe-, Mg-, and K-poor silicate glasses with compositions unlike that of the host lamprophyre. Larger, recrystallized melt inclusions contain analcime and calcite drawing a striking resemblance to leucocratic ocelli in the lamprophyre. We suggest here that sapphires formed through partial melting of Al-rich rocks, likely as the lamprophyre pooled at the base of the continental crust. This idea is corroborated by MELTS calculations on a kyanite-eclogite protolith which was presumably derived from a troctolite precursor. These calculations suggest that corundum can form through peritectic melting of kyanite. Linking the melt inclusions petrologically to the lamprophyre represents a significant advancement in our understanding of sapphire genesis and sheds light on how mantle-derived magmas may interact with the continental crust on their ascent to the surface.

  4. Synthesis of high capacity cation exchangers from a low-grade Chinese natural zeolite.

    Science.gov (United States)

    Wang, Yifei; Lin, Feng

    2009-07-30

    The Chinese natural zeolite, in which clinoptilolite coexists with quartz was treated hydrothermally with NaOH solutions, either with or without fusion with NaOH powder as pretreatment. Zeolite Na-P, Na-Y and analcime were identified as the reacted products, depending on the reaction conditions such as NaOH concentration, reaction time and hydrothermal temperature. The products were identified by X-ray diffraction, and characterized by Fourier transform IR and ICP. With hydrothermal treatment after fusion of natural zeolite with NaOH, high purity of zeolite Na-Y and Na-P can be selectively formed, their cation exchange capacity (CEC) are 275 and 355 meq/100g respectively, which are greatly higher than that of the natural zeolite (97 meq/100g). Furthermore, the ammonium removal by the synthetic zeolite Na-P in aqueous solution was also studied. The equilibrium isotherms have been got and the influence of other cations present in water upon the ammonia uptake suggested an order of preference Ca(2+)>K(+)>Mg(2+).

  5. Synthesis of high capacity cation exchangers from a low-grade Chinese natural zeolite

    Energy Technology Data Exchange (ETDEWEB)

    Wang Yifei, E-mail: yifeiwang0206@yahoo.com.cn [College of Biology and Chemical Engineering, Jiaxing University, Jiaxing, Zhejiang 314001 (China); Department of Chemistry, XiXi Campus, Zhejiang University, Hangzhou, Zhejiang 310028 (China); Lin Feng [Department of Chemistry, XiXi Campus, Zhejiang University, Hangzhou, Zhejiang 310028 (China)

    2009-07-30

    The Chinese natural zeolite, in which clinoptilolite coexists with quartz was treated hydrothermally with NaOH solutions, either with or without fusion with NaOH powder as pretreatment. Zeolite Na-P, Na-Y and analcime were identified as the reacted products, depending on the reaction conditions such as NaOH concentration, reaction time and hydrothermal temperature. The products were identified by X-ray diffraction, and characterized by Fourier transform IR and ICP. With hydrothermal treatment after fusion of natural zeolite with NaOH, high purity of zeolite Na-Y and Na-P can be selectively formed, their cation exchange capacity (CEC) are 275 and 355 meq/100 g respectively, which are greatly higher than that of the natural zeolite (97 meq/100 g). Furthermore, the ammonium removal by the synthetic zeolite Na-P in aqueous solution was also studied. The equilibrium isotherms have been got and the influence of other cations present in water upon the ammonia uptake suggested an order of preference Ca{sup 2+} > K{sup +} > Mg{sup 2+}.

  6. Mineralogía de los materiales de la Formación de La Viñuela (Cordilleras Béticas

    Directory of Open Access Journals (Sweden)

    Galán, E.

    1984-12-01

    Full Text Available Mineralogy of several samples from the Viñuela Formation,Lower Burdigalian (Vélez Málaga, Cordilleras Béticas, has been studied. Materials are composed of abundant microfauna. and pebbles of micaschits, quartzites and other materials, from the Alpujárrides and Maláguides Nappes, cemented by a micritic matrix . Most samples contain zeolites (clinoptilolite, mordenite and analcime, and illite chlorite, interstratified clay minerals, montmorillonite and opal C-T. A diagenetic genesis for zeolites is suggested.

    Se ha estudiado la composición mineralógica de unas muestras de la serie tipo de la Formación de La Viñuela (norte de Vélez Málaga, Cordilleras Béticas, datadas como Burdigaliense inferior. Se trata de sedimentos marinos carbonatados micríticos, con abundante microfauna. que cementan cantos de micaesquistos, cuarcitas y otros materiales procedentes de los mantos alpujárrides y maláguides. En gran parto de estas muestras se han encontrado zeolitas (clinoptilolita, mordenita y analcima, así como illita, clorita, interestratificados, montmorillonita y ópalo C-T. Se atribuye a las zeolitas un origen diagenético.

  7. Synthesis of zeolite phases from combustion by-products

    Energy Technology Data Exchange (ETDEWEB)

    Pimraksa, K.; Chindaprasirt, P.; Setthaya, N. [Chiang Mai University, Chiang Mai (Thailand). Dept. of Industrial Chemistry

    2010-12-15

    Synthesis of zeolites from combustion by-products, including fly ash, bottom ash and rice husk ash, was studied. A molar ratio of SiO{sub 2}/Al2O{sub 3} of 1.5 was used for the syntheses. Refluxing and hydrothermal methods were also used for synthesis for comparison. The reaction temperatures of refluxing and hydrothermal methods were 100{sup o}C and 130{sup o}C, respectively. Sodalite, phillipsite-K, and zeolite P1 with analcime were obtained when fly ash, bottom ash and rice husk ash were used as starting materials, respectively. With rice husk ash as a starting material, zeolite P1 was produced. This result had advantages over previous studies as there was no prior activation required for the synthesis. The concentrations and types of alkaline used in the synthesis also determined the zeolite type. The different zeolites obtained from three systems were measured for specific surface area and pore size by using BET and Hg-porosimetry, respectively. Ammonium exchange capacities of the synthesised powders containing zeolites, sodalite, zeolite P1 and phillipsite-K were 38.5, 65.0 and 154.7 meq 100 g{sup 1}, respectively.

  8. Synthesis of zeolite phases from combustion by-products.

    Science.gov (United States)

    Pimraksa, Kedsarin; Chindaprasirt, Prinya; Setthaya, Naruemon

    2010-12-01

    Synthesis of zeolites from combustion by-products, including fly ash, bottom ash and rice husk ash, was studied. A molar ratio of SiO2/Al2O3 of 1.5 was used for the syntheses. Refluxing and hydrothermal methods were also used for synthesis for comparison. The reaction temperatures of refluxing and hydrothermal methods were 100 degrees C and 130 degrees C, respectively. Sodalite, phillipsite-K, and zeolite P1 with analcime were obtained when fly ash, bottom ash and rice husk ash were used as starting materials, respectively. With rice husk ash as a starting material, zeolite P1 was produced. This result had advantages over previous studies as there was no prior activation required for the synthesis. The concentrations and types of alkaline used in the synthesis also determined the zeolite type. The different zeolites obtained from three systems were measured for specific surface area and pore size by using BET and Hg-porosimetry, respectively. Ammonium exchange capacities of the synthesised powders containing zeolites, sodalite, zeolite P1 and phillipsite-K were 38.5, 65.0 and 154.7 meq 100 g(-1), respectively.

  9. Fly ash from a Mexican mineral coal. II. Source of W zeolite and its effectiveness in arsenic (V) adsorption

    Energy Technology Data Exchange (ETDEWEB)

    Medina, Adriana [CINVESTAV IPN-Unidad Saltillo, Carretera Saltillo-Monterrey Km 13.5, C.P. 25900, Ramos Arizpe, Coahuila (Mexico); Gamero, Procoro, E-mail: pgamerom@hotmail.com [CINVESTAV IPN-Unidad Saltillo, Carretera Saltillo-Monterrey Km 13.5, C.P. 25900, Ramos Arizpe, Coahuila (Mexico); Almanza, Jose Manuel [CINVESTAV IPN-Unidad Saltillo, Carretera Saltillo-Monterrey Km 13.5, C.P. 25900, Ramos Arizpe, Coahuila (Mexico); Vargas, Alfredo; Montoya, Ascencion [Instituto Mexicano del Petroleo, Eje Central Lazaro Cardenas 152, G.A. Madero, C.P. 07730, Distrito Federal (Mexico); Vargas, Gregorio [CINVESTAV IPN-Unidad Saltillo, Carretera Saltillo-Monterrey Km 13.5, C.P. 25900, Ramos Arizpe, Coahuila (Mexico); Izquierdo, Maria [Instituto de Ciencias de la Tierra ' Jaume Almera' , CSIC, C/Luis Sole Sabaris, s/n 08028 Barcelona (Spain)

    2010-09-15

    Coal-fired plants in Coahuila (Mexico) produce highly reactive fly ash (MFA), which is used in a one-step process as a raw material in producing zeolite. We explored two routes in the synthesis of zeolite: (a) direct MFA zeolitization, which resulted in the formation of W zeolite with KOH and analcime with NaOH and (b) a MFA fusion route, which resulted in the formation of zeolite W or chabazite with KOH and zeolite X or P with NaOH. No residual crystalline phases were present. When LiOH was employed, ABW zeolite with quartz and mullite were obtained. For both zeolitization routes, the nature of the alkali (KOH, NaOH, LiOH), the alkali/MFA ratio (0.23-1.46), and the crystallization temperature and time (90-175 {sup o}C; 8-24 h) were evaluated. Additionally, the effect of temperature and time on MFA fusion was studied. W zeolite was obtained by both zeolitization methods. The direct route is preferred because it is a straightforward method using soft reaction conditions that results in a high yield of low cost zeolites with large crystal agglomerates. It was demonstrated that aluminum modified W zeolite has the ability to remove 99% of the arsenic (V) from an aqueous solution of Na{sub 2}HAsO{sub 4}.7H{sub 2}O originally containing 740 ppb.

  10. Single-crystal elastic properties of (Cs,Na)AlSi2O6.H2O pollucite: A zeolite with potential use for long-term storage of Cs radioisotopes

    Science.gov (United States)

    Sanchez-Valle, Carmen; Chio, Chi-Hong; Gatta, G. Diego

    2010-11-01

    The single-crystal and aggregate elastic properties of the zeolite pollucite (Cs,Na)AlSi2O6ṡH2O, a potential host for Cs radionucleides in geological repositories, have been determined by Brillouin scattering spectroscopy at ambient conditions. The three nonzero individual elastic constants of cubic pollucite are: C11=105.0(1.3) GPa, C44=27.0(3) GPa, and C12=25.7(6) GPa. The Voigt-Reuss-Hill average of the aggregate bulk, shear modulus, Young's modulus and Poisson's ratio are KS=52.2(1.0) GPa, G=31.5(7) GPa, E=78.6(1.0) GPa, and ν =0.248(4), respectively. The bulk modulus of pollucite is 12.7% lower than that of the all-Na isotypic mineral analcime NaAlSi2O6ṡH2O whereas the shear moduli G are identical within mutual uncertainties. The higher compressibility of pollucite results from the weaker Cs-O bonds compared to Na-O bonds, suggesting strong control of the nature and configuration of the extraframework content on the behavior of the structure. The elastic properties of pollucite reported here will help in the prediction of its behavior as a geological barrier and in the modeling of the short-term and long-term safety of the Cs-repositories.

  11. Catalytic decarboxylations of fatty acids in immature oil source rocks

    Institute of Scientific and Technical Information of China (English)

    李哲; 张再龙; 孙燕华; 劳永新; 蔺五正; 吴卫芳

    2003-01-01

    Catalytic decarboxylations of fatty acids in immature oil source rock samples were examined in this study. The rock samples were obtained from seven oil fields in China. In order to clarify the effect of each mineral matter in the rock samples, both the Fe M?ssbauer effect and the X-ray diffraction (XRD) were used to determine the relative content of each mineral in the rock samples, and the catalytic activities of several minerals like clays, carbonates and pyrite were determined. The Fe M?ssbauer effect and the XRD studies show that clays are the main mineral components in the rock samples except for the samples from Biyang and Jianghan in which the main mineral component is ankerite. The other mineral components include calcite, plagioclase, quartz, feldspar, siderite, aragonite, pyrite, analcime, pyroxene and anhydrite. The studies of the catalytic decarboxylations of fatty acids suggest that carbonates and pyrite can make much greater contributions to the catalytic activities of the rock samples than clays. It is found that the overall catalytic activities of the rock samples are well related to the relative contents and the catalytic activities of clays, carbonates and pyrite in the rock samples.

  12. Synthesis and catalytic properties of metal clusters encapsulated within small-pore (SOD, GIS, ANA) zeolites.

    Science.gov (United States)

    Goel, Sarika; Wu, Zhijie; Zones, Stacey I; Iglesia, Enrique

    2012-10-24

    The synthesis protocols for encapsulation of metal clusters reported here expand the diversity in catalytic chemistries made possible by the ability of microporous solids to select reactants, transition states, and products on the basis of their molecular size. We report a synthesis strategy for the encapsulation of noble metals and their oxides within SOD (Sodalite, 0.28 nm × 0.28 nm), GIS (Gismondine, 0.45 nm × 0.31 nm), and ANA (Analcime, 0.42 nm × 0.16 nm) zeolites. Encapsulation was achieved via direct hydrothermal synthesis for SOD and GIS using metal precursors stabilized by ammonia or organic amine ligands, which prevent their decomposition or precipitation as colloidal hydroxides at the conditions of hydrothermal synthesis (12), thereby causing precipitation of even ligand-stabilized metal precursors as hydroxides. As a result, encapsulation was achieved by the recrystallization of metal clusters containing GIS into ANA, which retained these metal clusters within voids throughout the GIS-ANA transformation.

  13. Alteration history of Mount Epomeo Green Tuff and a related polymictic breccia, Ischia Island, Italy: evidence for debris avalanche

    Science.gov (United States)

    Altaner, S.; Demosthenous, C.; Pozzuoli, A.; Rolandi, G.

    2013-05-01

    This paper presents mineralogical, chemical, and textural data for the Mount Epomeo Green Tuff and an associated polymictic breccia on Ischia Island, Italy with the purpose of defining the alteration history of the two units and the emplacement origin of the polymictic breccia. Our results indicate that the Green Tuff trachytic ignimbrite experienced three alteration events that produced the following mineral assemblages: (1) phillipsite, randomly interstratified (R0) illite/smectite (I/S), Fe-illite, and smectite (in situ Green Tuff); (2) chabazite, phillipsite, R0 I/S, and Fe-illite (proximal facies Green Tuff at Scarrupata di Barano); and (3) analcime, authigenic K-feldspar, Fe-illite, R0 I/S, and smectite (clasts of Green Tuff in polymictic breccia). Phillipsite, chabazite, and R0 I/S within the in situ and proximal facies Green Tuff indicate low-temperature alteration ( T 70 °C) alteration within a mostly closed chemical system. These data suggest that the polymictic breccia represents a debris avalanche deposit created by a catastrophic volcanic collapse, which was associated with low-temperature hydrothermal alteration and thus structural weakening of the volcano. The debris avalanche that produced the polymictic breccia on Ischia may be related to nearby massive debris avalanche deposits recently discovered offshore of southern Ischia. The young age of the polymictic breccia (5.7-8.6 ka) and the possibility of its catastrophic emplacement indicate an additional volcanic hazard for Ischia Island.

  14. Fly ash from a Mexican mineral coal. II. Source of W zeolite and its effectiveness in arsenic (V) adsorption.

    Science.gov (United States)

    Medina, Adriana; Gamero, Prócoro; Almanza, José Manuel; Vargas, Alfredo; Montoya, Ascención; Vargas, Gregorio; Izquierdo, María

    2010-09-15

    Coal-fired plants in Coahuila (Mexico) produce highly reactive fly ash (MFA), which is used in a one-step process as a raw material in producing zeolite. We explored two routes in the synthesis of zeolite: (a) direct MFA zeolitization, which resulted in the formation of W zeolite with KOH and analcime with NaOH and (b) a MFA fusion route, which resulted in the formation of zeolite W or chabazite with KOH and zeolite X or P with NaOH. No residual crystalline phases were present. When LiOH was employed, ABW zeolite with quartz and mullite were obtained. For both zeolitization routes, the nature of the alkali (KOH, NaOH, LiOH), the alkali/MFA ratio (0.23-1.46), and the crystallization temperature and time (90-175 degrees C; 8-24 h) were evaluated. Additionally, the effect of temperature and time on MFA fusion was studied. W zeolite was obtained by both zeolitization methods. The direct route is preferred because it is a straightforward method using soft reaction conditions that results in a high yield of low cost zeolites with large crystal agglomerates. It was demonstrated that aluminum modified W zeolite has the ability to remove 99% of the arsenic (V) from an aqueous solution of Na(2)HAsO(4).7H(2)O originally containing 740 ppb.

  15. A large volume cell for in situ neutron diffraction studies of hydrothermal crystallizations

    Science.gov (United States)

    Xia, Fang; Qian, Gujie; Brugger, Joël; Studer, Andrew; Olsen, Scott; Pring, Allan

    2010-10-01

    A hydrothermal cell with 320 ml internal volume has been designed and constructed for in situ neutron diffraction studies of hydrothermal crystallizations. The cell design adopts a dumbbell configuration assembled with standard commercial stainless steel components and a zero-scattering Ti-Zr alloy sample compartment. The fluid movement and heat transfer are simply driven by natural convection due to the natural temperature gradient along the fluid path, so that the temperature at the sample compartment can be stably sustained by heating the fluid in the bottom fluid reservoir. The cell can operate at temperatures up to 300 °C and pressures up to 90 bars and is suitable for studying reactions requiring a large volume of hydrothermal fluid to damp out the negative effect from the change of fluid composition during the course of the reactions. The capability of the cell was demonstrated by a hydrothermal phase transformation investigation from leucite (KAlSi2O6) to analcime (NaAlSi2O6ṡH2O) at 210 °C on the high intensity powder diffractometer Wombat in ANSTO. The kinetics of the transformation has been resolved by collecting diffraction patterns every 10 min followed by Rietveld quantitative phase analysis. The classical Avrami/Arrhenius analysis gives an activation energy of 82.3±1.1 kJ mol-1. Estimations of the reaction rate under natural environments by extrapolations agree well with petrological observations.

  16. Geochemical inputs for hydrological models of deep-lying sedimentary units: Loss of mineral hydration water

    Science.gov (United States)

    Graf, D. L.; Anderson, D. E.

    1981-12-01

    Hydrological models that treat phenomena occurring deep in sedimentary piles, such as petroleum maturation and retention of chemical and radioactive waste, may require time spans of at least several million years. Many input quantities classically treated as constants will be variables on this time scale. Models sophisticated enough to include transport contributions from such processes as chemical diffusion, mineral dehydration and shale membrane behavior require considerable knowledge about regional geological history as well as the pertinent mineralogical and geochemical relationships. Simple dehydrations such as those of gypsum and halloysite occur at sharply-defined temperatures but, as with all mineral dehydration reactions, the equilibrium temperature is strongly dependent on the pore-fluid salinity and degree of overpressuring encountered in the subsurface. The dehydrations of analcime and smectite proceed by reactions involving other sedimentary minerals. The smectite reaction is crystallographically complex, yielding a succession of mixed-layered illite/smectites, and on the U.S.A. Gulf of Mexico coast continues over several million years at a particular stratigraphic interval.

  17. Experimental alteration of artificial and natural impact melt rock from the Chesapeake Bay impact structure

    Science.gov (United States)

    Declercq, J.; Dypvik, H.; Aagaard, P.; Jahren, J.; Ferrell, R.E.; Horton, J. Wright

    2009-01-01

    The alteration or transformation of impact melt rock to clay minerals, particularly smectite, has been recognized in several impact structures (e.g., Ries, Chicxulub, Mj??lnir). We studied the experimental alteration of two natural impact melt rocks from suevite clasts that were recovered from drill cores into the Chesapeake Bay impact structure and two synthetic glasses. These experiments were conducted at hydrothermal temperature (265 ??C) in order to reproduce conditions found in meltbearing deposits in the first thousand years after deposition. The experimental results were compared to geochemical modeling (PHREEQC) of the same alteration and to original mineral assemblages in the natural melt rock samples. In the alteration experiments, clay minerals formed on the surfaces of the melt particles and as fine-grained suspended material. Authigenic expanding clay minerals (saponite and Ca-smectite) and vermiculite/chlorite (clinochlore) were identified in addition to analcime. Ferripyrophyllite was formed in three of four experiments. Comparable minerals were predicted in the PHREEQC modeling. A comparison between the phases formed in our experiments and those in the cores suggests that the natural alteration occurred under hydrothermal conditions similar to those reproduced in the experiment. ?? 2009 The Geological Society of America.

  18. Metamorfismo de muy bajo grado asociado a un sistema geotermal en rocas volcánicas básicas del Jurásico Medio, Formación Lonco Trapial, Paso Berwin, Chubut extra-andino Very low grade metamorphism associated with a geothermal system in basic volcanic rocks of the Middle Jurassic, Lonco Trapial Formation, Paso Berwin, Extra-Andean Chubut

    Directory of Open Access Journals (Sweden)

    P. Montecinos

    2004-12-01

    Full Text Available Las rocas volcánicas básicas de la Formación Lonco Trapial, poseen una mineralogía primaria compuesta principalmente por olivino, plagioclasa cálcica y piroxeno, presentando además gran cantidad de amígdalas. La mineralogía metamórfica de muy bajo grado en estas rocas está caracterizada por ceolitas, minerales arcillosos y micáceos. La asociación mineral más característica está compuesta por celadonita, montmorillonita, heulandita, analcima, gonnardita y, además, por levyna y minerales de la serie analcima-wairakita en forma subordinada. Esta asociación pertenece a la facies ceolita y tuvo un origen asociado a un sistema geotermal. La analogía establecida con las zonas de ceolitas conocidas para sistemas geotermales equivalentes y el uso de la grilla petrogénetica para paragénesis ceolíticas, en el sistema An-Ab-SiO2-H2O, permiten establecer un rango de temperatura entre 80°-180°C. En este contexto habría ocurrido un único evento metamórfico hidrotermal en presencia de una fase fluida, muy pobre en CO2, cuya composición química habría cambiado desde un carácter neutro con baja a(SiO2 y a(K2O moderada (permitiendo la precipitación de esmectitas y celadonita a un carácter neutro-alcalino con a(SiO2 que posibilita la estabilidad de la heulandita.The basic volcanic rocks of the Lonco Trapial Formation, have a primary mineralogy mainly composed of olivine, calcic plagioclase and pyroxene, and present a large quantity of amygdales. Their metamorphic mineralogy is characterized by zeolites, clay and micaceous minerals. The main mineral association includes celadonite, montmorillonite, heulandite, analcime, gonnardite and subordinate levyne and minerals of the wairakite-analcime series. This association belongs to the zeolite facies and its origin was associated with a geothermal system. The analogy with known zeolite zones in equivalent geothermal systems and the use of the petrogenetic grid for zeolite parageneses, in

  19. The heat capacity of hydrous cordierite above 295 K

    Science.gov (United States)

    Carey, J. William

    1993-04-01

    The heat capacity of synthetic hydrous cordierite (Mg2Al4Si5O18·nH2O) has been determined by differential scanning calorimetry (DSC) from 295 to 425 K as a function of H2O content. Six samples with H2O contents ranging from 0 to 0.82 per formula unit were examined. The partial molar heat capacity of H2O in cordierite over the measured temperature interval is independent of composition and temperature within experimental uncertainty and is equal to 43.3 ±0.8 J/mol/ K. This value exceeds the molar heat capacity of gaseous H2O by 9.7 J/mol/K, but is significantly smaller than the heat capacity of H2O in several zeolites and liquid H2O. A statistical-mechanical model of the heat capacity of adsorbed gas species (Barrer 1978) is used to extrapolate the heat capacity of hydrous cordierite to temperatures greater than 425 K. In this model, the heat capacity of hydrous cordierite (Crd·nH2O) is represented as follows: Cp(Crd · nH2O) = Cp(Crd)+ n{Cp(H2O, gas)+ R(gas constant)} (1) An examination of calorimetric data for hydrous beryl, analcime, mordenite, and clinoptilolite (Hemingway et al. 1986; Johnson et al. 1982, 1991, 1992) demonstrates the general applicability of the statistical-mechanical model for the extrapolation of heat capacity data of zeolitic minerals. The heat capacity data for cordierite are combined with the data of Carey and Navrotsky (1992) to obtain the molar enthalpy of formation and enthalpy of hydration of hydrous cordierite as a function of temperature.

  20. Synthesis of zeolites from boiler fly ash: physical, chemical and mineralogical characterization; Sintese de zeolitas a partir de cinza volante de caldeiras: caracterizacao fisica, quimica e mineralogica

    Energy Technology Data Exchange (ETDEWEB)

    Rocha Junior, C.A.F.; Santos, S.C.A.; Souza, C.A.G., E-mail: augustorocha2@gmail.com [Programa de Pos Graduacao em Engenharia Quimica (PPEQ-UFPA), Belem, PA (Brazil); Angelica, R.S.; Neves, R.F. [Programa de Pos-Graduacao em Geologia e Geoquimica, Instituto de Geociencias (PPGG-IG-UFPA), Ananindeua, PA (Brazil)

    2012-01-15

    Along the years, worldwide industrial development has causing a growing generation of residues, bringing potentials environmental problems. A study of the characteristics of these wastes, as well as the development of techniques for their use in new processes becomes indispensable for the environment preservation. The main purpose of this work is to evaluate the possible use of two important industrial residues from the Amazon region for zeolite synthesis: (a) the fly ash (particle size < 100 {mu}m) that comes from burning of mineral coal in boiler; and (b) the micro silica, a by-product of the reaction between quartz and coal in the production of metallic silicon and alloys iron-silicon.The following chemical, physical and mineralogical characterization methods were carried out: X-ray diffractometry, X-ray fluorescence, scanning electron microscopy, granulometric analysis, differential thermal and thermogravimetric analysis (DTA-TG). The analyses were carried out at the following conditions: 60, 100, 150 and 190 deg C, Na{sub 2}O/Al{sub 2}O{sub 3} molar ratio of 5 and Si/Al molar ratio ranging from 2.12 to 15, and reaction time of 24 h. The results of the fly characterization demonstrate its enormous potential as raw material for the zeolite synthesis. SiO{sub 2} and Al{sub 2}O{sub 3} represent more than 50% of its composition, mineralogical phases defined, low humidity content, low particle size (d{sub 90} < 10 {mu}m), among others. Mineralogical analyses of the synthesized products showed the formation of some zeolite types, as follow: analcime, phillipsite, sodalite, zeolite P and tobermorite. The results show that the mixture fly ash-micro silica in these reaction conditions point to a promising material for zeolite synthesis (author)

  1. Groundwater prospecting for sandstone-type uranium deposits: the merits of mineral-solution equilibria versus single element tracer methods. Volume II

    Energy Technology Data Exchange (ETDEWEB)

    Wanty, R.B.; Langmuir, D.; Chatham, J.R.

    1981-08-01

    This report presents the results of further research on the groundwater geochemistry of 96 well waters in two uraniferous aquifers in Texas and Wyoming, and is a continuation of the work presented by Chatham et al. (1981). In this study variations in concentrations of U, As, Mo, Se and V were compared with the saturation state of the groundwater with respect to mineral phases of these elements known or expected to occur in each area. The non-radiogenic trace elements exhibited strong redox dependence consistent with thermodynamic predictions, but their variations did not pinpoint existing uranium ore bodies, because of a shift in groundwater flow patterns since the time of ore emplacement. Saturation levels of trace element minerals such as realgar, native Se, and molybdenite showed broad anomalies around the ore-bearing areas, similar to patterns found for U minerals by Langmuir and Chatham (1980), and Chatham et al. (1981). The radiogenic elements Ra and Rn showed significant anomalies directly within the ore zones. Helium anomalies were displaced in the direction of groundwater flow, but by their magnitude and areal extent provided strong evidence for the existence of nearby uranium accumulations. Uranium isotope ratios showed no systematic variations within the two aquifers studied. Saturation maps for kaolinite, illite, montmorillonite and the zeolites analcime and clinoptilolite provided 1 to 2 km anomalies around the ore at the Texas site. Saturation values for the gangue minerals pyrite and calcite defined the redox interface and often suggested the position of probable uranium mineralization. When properly used, the groundwater geochemical concepts for exploration can accurately pinpoint uranium mineralization at a fraction of the cost of conventional methods that involve test drilling and geophysical and core logging.

  2. Revised mineralogic summary of Yucca Mountain, Nevada

    Energy Technology Data Exchange (ETDEWEB)

    Bish, D.L.; Chipera, S.J.

    1989-03-01

    We have evaluated three-dimensional mineral distribution at Yucca Mountain, Nevada, using quantitative x-ray powder diffraction analysis. All data were obtained on core cuttings, or sidewall samples obtained from drill holes at and around Yucca Mountain. Previously published data are included with corrections, together with new data for several drill holes. The new data presented in this report used the internal standard method of quantitative analysis, which yields results of high precision for the phases commonly found in Yucca Mountain tuffs including opal-CT and glass. Mineralogical trends with depth previously noted are clearly shown by these new data. Glass occurrence is restricted almost without exception to above the present-day static water level (SWL), although glass has been identified below the SWL in partially zeolitized tuffs. Silica phases undergo well-defined transitions with depth, with tridymite and cristobalite occurring only above the SWL, opal-CT occurring with clinoptilolite-mordenite tuffs, and quartz most abundant below the SWL. Smectite occurs in small amounts in most samples but is enriched in two distinct zones. These zones are at the top of the vitric nonwelded base of the Tiva Canyon Member and at the top of the basal vitrophyre of the Topopah Spring Member. Our data support the presence of several zones of mordenite and clinoptilolite-heulandite as shown previously. New data on several deep clinoptililite-heulandite samples coexisting with analcime show that they are heulandite. Phillipsite has not been found in any Yucca Mountain samples, but erionite and chabazite have been found once in fractures. 21 refs., 17 figs.

  3. Understanding the dissolution of zeolites.

    Science.gov (United States)

    Hartman, Ryan L; Fogler, H Scott

    2007-05-08

    Scientific knowledge of how zeolites, a unique classification of microporous aluminosilicates, undergo dissolution in aqueous hydrochloric acid solutions is limited. Understanding the dissolution of zeolites is fundamental to a number of processes occurring in nature and throughout industry. To better understand the dissolution process, experiments were carried out establishing that the Si-to-Al ratio controls zeolite framework dissolution, by which the selective removal of aluminum constrains the removal of silicon. Stoichiometric dissolution is observed for Type 4A zeolite in HCl where the Si-to-Al ratio is equal to 1.0. Framework silicon dissolves completely during Type 4A dissolution and is followed by silicate precipitation. However, for the zeolite analcime which has a Si-to-Al ratio of 2.0 dissolves non-stoichiometrically as the selective removal of aluminum results in partially dissolved silicate particles followed by silicate precipitation. In Type Y zeolite, exhibiting a Si-to-Al ratio of 3.0, there is insufficient aluminum to weaken the structure and cause silicon to dissolve in HCl. Thus, little or no precipitation is observed, and amorphous undissolvable silicate particles remain intact. The initial dissolution rates of Type Y and 4A zeolites demonstrate that dissolution is constrained by the number of available reaction sites, and a selective removal rate parameter is applied to delineate the mechanism of particle dissolution by demonstrating the kinetic influence of the Si-to-Al ratio. Zeolite framework models are constructed and used to undergird the basic dissolution mechanism. The framework models, scanning electron micrographs of partially dissolved crystals, and experimentally measured dissolution rates all demonstrate that a zeolite's Si-to-Al framework ratio plays a universal role in the dissolution mechanism, independent of framework type. Consequently, the unique mechanism of zeolite dissolution has general implications on how petroleum

  4. Reactivity of the cement-bentonite interface with alkaline solutions using transport cells

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez, Raul [Dpto. Quimica Agricola, Geologia y Geoquimica, Facultad de Ciencias, Universidad Autonoma de Madrid, Campus Cantoblanco, 28049 Madrid (Spain); Cuevas, Jaime [Dpto. Quimica Agricola, Geologia y Geoquimica, Facultad de Ciencias, Universidad Autonoma de Madrid, Campus Cantoblanco, 28049 Madrid (Spain)]. E-mail: jaime.cuevas@uam.es; Sanchez, Laura [Dpto. Quimica Agricola, Geologia y Geoquimica, Facultad de Ciencias, Universidad Autonoma de Madrid, Campus Cantoblanco, 28049 Madrid (Spain); Villa, Raquel Vigil de la [Dpto. Quimica Agricola, Geologia y Geoquimica, Facultad de Ciencias, Universidad Autonoma de Madrid, Campus Cantoblanco, 28049 Madrid (Spain); Leguey, Santiago [Dpto. Quimica Agricola, Geologia y Geoquimica, Facultad de Ciencias, Universidad Autonoma de Madrid, Campus Cantoblanco, 28049 Madrid (Spain)

    2006-06-15

    Clayey formations are considered as suitable host rocks to develop a Deep Geological Repository (DGR) for nuclear wastes. A concrete ring, located between the clayey formation and the bentonite barrier, is needed as structural support for the galleries. This material will act as a source of alkaline fluids when the formation's pore water saturates the system. This investigation evaluates the performance of the concrete-bentonite system by means of both geochemical codes and experimental results. A column made of compacted bentonite from La Serrata (Almeria, Spain) (1.4 g/cm{sup 3}, dry density) was held in contact with an ordinary Portland cement (OPC) mortar. Two alkaline solutions (Ca(OH){sub 2} saturated and NaOH 0.25 M) were injected from the mortar's side at 25, 60 and 120 deg. C. The permeability of the system and the effluent fluid composition were determined periodically. Finally, the solid phase was sampled and analyzed after 1 year of treatment. Ca(OH){sub 2} saturated fluids does not alter the mineralogy over the experiment time scale. NaOH fluids produced minor changes at 60-25 deg. C but at 120 deg. C a thin tobermorite layer of 1.5 mm precipitates in the clay aggregate surfaces at the interface. After this layer, analcime nucleates in heterogeneous patches affecting the whole compacted bentonite probe (2 cm thickness). The use of the PHREEQC code thermodynamic approach predicts the mineralogical transformations. However, it is necessary to introduce kinetic laws and to consider the existence of stagnant zones in the model in order to simulate the heterogeneous spatial alteration observed.

  5. Immobilization of simulated low and intermediate level waste in alkali-activated slag-fly ash-metakaolin hydroceramics

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jin, E-mail: wjin761026@163.com [State Key Laboratory Cultivation Base for Nonmetal Composite and Functional Materials, Southwest University of Science and Technology, Mianyang 621010, Sichuan (China); School of Materials Science and Engineering, Southwest University of Science and Technology, Mianyang 621010, Sichuan (China); Wang, Jun-xia; Zhang, Qin [School of Materials Science and Engineering, Southwest University of Science and Technology, Mianyang 621010, Sichuan (China); Li, Yu-xiang [State Key Laboratory Cultivation Base for Nonmetal Composite and Functional Materials, Southwest University of Science and Technology, Mianyang 621010, Sichuan (China); School of Materials Science and Engineering, Southwest University of Science and Technology, Mianyang 621010, Sichuan (China)

    2016-04-15

    Highlights: • Evaluation of the suitability of ASFMH for solidifying simulated S-LILW. • The introduction of S-LILW avails forming zeolitic phases of ASFMH waste forms. • The ASFMH waste forms have low leachability and high compressive strength. - Abstract: In the current study, the alkali-activated slag-fly ash-metakaolin hydroceramic (ASFMH) waste forms for immobilizing simulated low and intermediate level waste (S-LILW) were prepared by hydrothermal process. The crystalline phase compositions, morphology, compressive strength and aqueous stability of S-LILW ASFMH waste forms were investigated. The results showed that the main crystalline phases of S-LILW ASFMH waste forms were analcime and zeolite NaP1. The changes of Si/Al molar ratio (from 1.7 to 2.2) and Ca/Al molar ratio (from 0.15 to 0.35) had little effect on the phase compositions of S-LILW ASFMH waste forms. However, the hydrothermal temperature, time as well as the content of S-LILW (from 12.5 to 37.5 wt%) had a major impact on the phase compositions. The compressive strength of S-LILW ASFMH waste forms was not less than 20 MPa when the content of S-LILW reached 37.5 wt%. In addition, the aqueous stability testing was carried out using the standard MCC-1 static leach test method; the normalized elemental leach rates of Sr and Cs were fairly constant in a low value below 5 × 10{sup −4} g m{sup −2} d{sup −1} and 3 × 10{sup −4} g m{sup −2} d{sup −1} after 28 days, respectively. It is indicated that ASFMH waste form could be a potential host for safely immobilizing LILW.

  6. Indikasi mineralisasi epitermal emas bersulfi da rendah, di Wilayah Kecamatan Bonjol, Kabupaten Pasaman, Sumatera Barat

    Directory of Open Access Journals (Sweden)

    Hamdan Z. Abidin

    2014-06-01

    Full Text Available http://dx.doi.org/10.17014/ijog.vol2no1.20075Bonjol gold prospect, known as Old Dutch Gold mine, consists of several ore bodies (Malintang, Balimbing, Lubang Sempit, Lubang Belanda and Lubang Perak. The deposit hosts within the altered volcanic rocks known as Gunung Amas Formation of Early Miocene age (9.3 ± 0.4 - 11.9 ±1.0 Ma. This formation consists of various rock types such as rhyolitic tuff, volcanic breccia, dacitic tuffs and rhyolites. These rocks are moderate to strongly alter. Mineralogy of the deposit consists of gold and silver with minor pyrite, sphalerite and galena. Besides this, hematite, jarosite and manganese are also present as supergene minerals. Ore minerals are found within quartz veins ranging from few centimetres to tens of metres thick. The veins are characterized by crustiform, comb, vuggy, botroyidal, layering and bladed. Quartz is a dominant mineral as hydrothermal alteration in addition to illite, dickite, monmorillonite, kaolinite, chlorite, smectite, natrolite, nontronite, calcite, halloysite, palygorskite, muscovite, sepiolite, analcime, heulandite, clino-chlor, zircon, zoisite, laumontite, alunite, biotite and erionite. The presence of these secondary minerals could be classifi ed into prophylitic, argillic and advanced argillic types. Analytical result of gold–bearing quartz vein indicates higher content of gold (0.3% and silver (400 ppm. In contrast, the content of sulphide minerals (Cu, Pb, and Zn is very low (< 100 ppm. Combined geology, mineralogy, textures and alteration minerals, it is concluded that gold deposit in the area shows an indication of a low sulphidation epithermal type within Gunung Amas Formation.  

  7. Deep Boreholes Seals Subjected to High P,T conditions - Proposed Experimental Studies

    Science.gov (United States)

    Caporuscio, F.

    2015-12-01

    Deep borehole experimental work will constrain the P,T conditions which "seal" material will experience in deep borehole crystalline rock repositories. The rocks of interest to this study include mafic (amphibolites) and silicic (granitic gneiss) end members. The experiments will systematically add components to capture discrete changes in both water and EBS component chemistries. Experiments in the system wall rock-clay-concrete-groundwater will evaluate interactions among components, including: mineral phase stability, metal corrosion rates and thermal limits. Based on engineered barrier studies, experimental investigations will move forward with three focusses. First, evaluation of interaction between "seal" materials and repository wall rock (crystalline) under fluid-saturated conditions over long-term (i.e., six-month) experiments; which reproduces the thermal pulse event of a repository. Second, perform experiments to determine the stability of zeolite minerals (analcime-wairakitess) under repository conditions. Both sets of experiments are critically important for understanding mineral paragenesis (zeolites and/or clay transformations) associated with "seals" in contact with wall rock at elevated temperatures. Third, mineral growth at the metal interface is a principal control on the survivability (i.e. corrosion) of waste canisters in a repository. The objective of this planned experimental work is to evaluate physio-chemical processes for 'seal' components and materials relevant to deep borehole disposal. These evaluations will encompass multi-laboratory efforts for the development of seals concepts and application of Thermal-Mechanical-Chemical (TMC) modeling work to assess barrier material interactions with subsurface fluids and other barrier materials, their stability at high temperatures, and the implications of these processes to the evaluation of thermal limits.

  8. Thermal Conductivity of Pyroclastic Soil ( Pozzolana) from the Environs of Rome

    Science.gov (United States)

    McCombie, M. L.; Tarnawski, V. R.; Bovesecchi, G.; Coppa, P.; Leong, W. H.

    2017-02-01

    The paper reveals the experimental procedure and thermo-physical characteristics of a coarse pyroclastic soil ( Pozzolana), from the neighborhoods of Rome, Italy. The tested samples are comprised of 70.7 % sand, 25.9 % silt, and 3.4 % clay. Their mineral composition contained 38 % pyroxene, 33 % analcime, 20 % leucite, 6 % illite/muscovite, 3 % magnetite, and no quartz content was noted. The effective thermal conductivity of minerals was assessed to be about 2.14 W{\\cdot } m^{-1}{\\cdot } K^{-1}. A transient thermal probe method was applied to measure the thermal conductivity (λ ) over a full range of the degree of saturation (Sr), at two porosities ( n) of 0.44 and 0.50, and at room temperature of about 25°C. The λ data obtained were consistent between tests and showed an increasing trend with increasing Sr and decreasing n. At full saturation (Sr=1), a nearly quintuple λ increase was observed with respect to full dryness (Sr=0). In general, the measured data closely followed the natural trend of λ versus Sr exhibited by published data at room temperature for other unsaturated soils and sands. The measured λ data had an average root-mean-squared error (RMSE) of 0.007 W{\\cdot } m^{-1}{\\cdot } K^{-1} and 0.008 W{\\cdot } m^{-1}{\\cdot } K^{-1} for n of 0.50 and 0.44, respectively, as well as an average relative standard deviation of the mean at the 95 % confidence level (RSDM_{0.95}) of 2.21 % and 2.72 % for n of 0.50 and 0.44, respectively.

  9. Predictive hydrogeochemical modelling of bauxite residue sand in field conditions.

    Science.gov (United States)

    Wissmeier, Laurin; Barry, David A; Phillips, Ian R

    2011-07-15

    The suitability of residue sand (the coarse fraction remaining from Bayer's process of bauxite refining) for constructing the surface cover of closed bauxite residue storage areas was investigated. Specifically, its properties as a medium for plant growth are of interest to ensure residue sand can support a sustainable ecosystem following site closure. The geochemical evolution of the residue sand under field conditions, its plant nutrient status and soil moisture retention were studied by integrated modelling of geochemical and hydrological processes. For the parameterization of mineral reactions, amounts and reaction kinetics of the mineral phases natron, calcite, tricalcium aluminate, sodalite, muscovite and analcime were derived from measured acid neutralization curves. The effective exchange capacity for ion adsorption was measured using three independent exchange methods. The geochemical model, which accounts for mineral reactions, cation exchange and activity corrected solution speciation, was formulated in the geochemical modelling framework PHREEQC, and partially validated in a saturated-flow column experiment. For the integration of variably saturated flow with multi-component solute transport in heterogeneous 2D domains, a coupling of PHREEQC with the multi-purpose finite-element solver COMSOL was established. The integrated hydrogeochemical model was applied to predict water availability and quality in a vertical flow lysimeter and a cover design for a storage facility using measured time series of rainfall and evaporation from southwest Western Australia. In both scenarios the sand was fertigated and gypsum-amended. Results show poor long-term retention of fertilizer ions and buffering of the pH around 10 for more than 5 y of leaching. It was concluded that fertigation, gypsum amendment and rainfall leaching alone were insufficient to render the geochemical conditions of residue sand suitable for optimal plant growth within the given timeframe. The

  10. Seizure modeling of Pb(II) and Cd(II) from aqueous solution by chemically modified sugarcane bagasse fly ash: isotherms, kinetics, and column study.

    Science.gov (United States)

    Shah, Bhavna; Mistry, Chirag; Shah, Ajay

    2013-04-01

    Heavy metal pollution is a common environmental problem all over the world. The purpose of the research is to examine the applicability of bagasse fly ash (BFA)-an agricultural waste of sugar industry used for the synthesis of zeolitic material. The zeolitic material are used for the uptake of Pb(II) and Cd(II) heavy metal. Bagasse fly ash is used as a native material for the synthesis of zeolitic materials by conventional hydrothermal treatment without (conventional zeolitic bagasse fly ash (CZBFA)) and with electrolyte (conventional zeolitic bagasse fly ash in electrolyte media (ECZBFA)) media. Heavy metal ions Pb(II) and Cd(II) were successfully seized from aqueous media using these synthesized zeolitic materials. In this study, the zeolitic materials were well characterized by different instrumental methods such as Brunauer-Emmett-Teller, XRF, Fourier transform infrared spectroscopy, powder X-ray diffraction, and scanning electron microscopic microphotographs. The presence of analcime, phillipsite, and zeolite P in adsorbents confirms successful conversion of native BFA into zeolitic materials. Seizure modeling of Pb(II) and Cd(II) was achieved by batch sorption experiments, isotherms, and kinetic studies. These data were used to compare and evaluate the zeolitic materials as potential sorbents for the uptake of heavy metal ions from an aqueous media. The Langmuir isotherm correlation coefficient parameters best fit the equilibrium data which indicate the physical sorption. Pseudo-second-order and intra-particle diffusion model matches best which indicates that the rate of sorption was controlled by film diffusion. The column studies were performed for the practical function of sorbents, and breakthrough curves were obtained, which revealed higher sorption capacity as compared to batch method. Synthesized zeolitic material (CZBFA and ECZBFA), a low-cost sorbent, was proven as potential sorbent for the uptake of Pb(II) and Cd(II) heavy metal ions.

  11. Hydrothermal Alteration of Hyaloclastites Adjacent to Sill-Like Intrusives in the HSDP 3-km Core Hole.

    Science.gov (United States)

    McClain, J. S.; Schiffman, P.; Walton, A. W.; Yin, Q.; Pauly, B.

    2008-12-01

    Hyaloclastites at present depths below1880 mbsl on the submarine flanks of Mauna Kea volcano have been intruded by numerous, < 10 m-thick, sill-like bodies. The contact metamorphism of the hyaloclastites has resulted in up to 1 m-thick bleached zones, characterized by the presence of Na-and Mg-enriched alteration rinds on sideromelane clasts as well as the precipitation of drusy hydrothermal clinopyroxene (calcic augite to hedenbergite) and analcime within void spaces. The intrusive activity associated with contact metamorphism appears to have occurred early in the diagenetic history of the hylaoclastites, when they possessed porosities of 40-50%, because (1) early induration and pore-filling by hydrothermal minerals apparently strengthened them, preventing significant grain compaction during subsequent burial, (2) hydrothermal minerals have been coated or overgrown by smectite, zeolites, and palagonite during subsequent diagenesis and microbial innoculation, and (3) 87Sr/86Sr ratios of hydrothermal rinds on glass shards, averaging .7069 ± .0006, imply extensive interaction with seawater, whereas 87Sr/86Sr ratios of adjacent palagonitized glass, averaging .7042 ± .0002, imply interaction with comparatively less fluid, presumably after diagenetic pore-filling. Thermal modeling, which assumes (1) convective cooling, (2) that hydrothermal clinopyroxenes formed at minimum temperatures of 350°C, and (3) that hyaloclastite porosities approached 50% at the time of intrusion, implies that the observed contact aureoles must have been produced by mafic intrusions that maintained temperatures above the solidus rather than being rapidly cooled and frozen. This may have occurred because magma continued to flow in the intrusion conduit, consistent with the suggestion that these intrusions fed overlying pillow flows (Garcia et al., 2007). If this intrusive activity occurred at shallow depths within the edifice of Mauna Kea (Seaman et al. 2004), then hydrothermal clinopyroxene

  12. The Gem Mineralogy Researching for Guatemala Jade%危地马拉翡翠的宝石矿物学研究

    Institute of Scientific and Technical Information of China (English)

    陈晶晶; 何明跃; 白志民

    2012-01-01

    利用电子探针(PXRF)、X射线粉末衍射(XRD)及红外光谱(FIR)等技术手段对危地马拉翡翠样品进行分析,并与缅甸翡翠的宝石矿物学特征进行对比研究.结果表明,危地马拉翡翠的化学成分与硬玉的基本相同.矿物组成主要为硬玉,并且含有钠长石、白云母以及少量金云母、黝帘石、榍石和方沸石等.结构主要为柱粒状变晶结构与碎裂结构,是导致其质地较粗的主要原因之一.红外光谱与缅甸翡翠的红外光谱相比有明显漂移.%The samples of Guatemala jadeite were analyzed by electron probe analysis (EP), X-ray powder diffraction (XRD) and infrared spectroscopy (IR), and compared with the gem mineralogical characteristics of the Burma jade. Which shows that the chemical compositions of jadeite are as same as the jade's in Guatemala. The main minerals in Guatemala jadeite are jade containing albite, muscovite, and few phlogopite, zoisite, titanite and analcime; the main structures are columnargrain metacryst structure and cataclastic texture structure, which is one of the mainly reasons why their texture are crude; the infrared spectroscopy of Guatemala jade is drifted obviously than the Burma jade's.

  13. SODIUM POLYPHOSPHATE-MODIFIED CLASS C/CLASS F FLY ASH BLEND CEMENTS FOR GEOTHERMAL WELLS.

    Energy Technology Data Exchange (ETDEWEB)

    SUGAMA, T.; BROTHERS, L.E.; KASPEREIT, D.

    2006-02-01

    The authors investigated the usefulness of the coal combustion by-products, Class C fly ash (C) and Class F fly ash (F), in developing cost-effective acid-resistant phosphate-based cements for geothermal wells. In the temperature range of 20-100 C, sodium polyphosphate (NaP) as the acidic cement-forming solution preferentially reacted with calcium sulfate and lime in the C as the base solid reactant through the exothermic acid-base reaction route, rather than with the tricalcium aluminate in C. This reaction led to the formation of hydroxyapatite (HOAp). In contrast, there was no acid-base reaction between the F as the acidic solid reactant and NaP. After autoclaving the cements at 250 C, a well-crystallized HOAp phase was formed in the NaP-modified C cement that was responsible for densifying the cement's structure, thereby conferring low water permeability and good compressive strength on the cement. however, the HOAp was susceptible to hot CO{sub 2}-laden H{sub 2}SO{sub 4} solution (pH 1.1), allowing some acid erosion of the cement. On the other hand, the mullite in F hydrothermally reacted with the Na from NaP to form the analcime phase. Although this phase played a pivotal role in abating acid erosion, its generation created an undesirable porous structure in the cement. They demonstrated that blending fly ash with a C/F ratio of 70/30 resulted in the most suitable properties for acid-resistant phosphate-based cement systems.

  14. Depositional conditions of the coal-bearing Hirka Formation beneath Late Miocene explosive volcanic products in NW central Anatolia, Turkey

    Indian Academy of Sciences (India)

    Mehmet Şener

    2007-04-01

    This work focuses on the relationship between the coal deposition and explosive volcanism of the Miocene basin, NW central Anatolia, Turkey. The coal-bearing Hirka Formation was deposited over the Galatian Andesitic Complex and/or massive lagoonal environments during the Miocene. The investigated lignite is a high ash (from 32 to 58%) and sulphur (from 1.43 to 3.03%) lignite which is petrographically characterised by a high humunite content. The mineral matter of the studied lignite samples is made up of mainly clay minerals (illite–smectite and kaolinite), plagioclase and quartz in Bolu coal field, clay minerals (illite–smectite, smectite and illite), quartz, calcite, plagioclase and gypsum in Seben coal field, quartz, K-feldspar, plagioclase and clay minerals (kaolinite and illite) in Kıbrıscık, and dolomite, quartz, clinoptilolite, opal CT and gypsum in C¸ amlıdere coal field. The differences in these four types of lignite with specific mineralogical patterns may be due to the explosive volcanic events and depositional conditions which changed from one coal field to the others. There is a zonation from SW to SE in the studied area for zeolites such as Opal CT+smectite-clinoptilolite-analcime-K-feldspar. Carbonate minerals are commonly calcite in Seben and Kıbrıscık coal fields. In Bolu, coal samples are devoid of calcite and dolomite. These analyses show that there is an increase in the amount of Mg and a decrease in the amount of Na from the northwestern part to the southern part in the study area.

  15. Raman-Mössbauer-XRD studies of selected samples from "Los Azulejos" outcrop: A possible analogue for assessing the alteration processes on Mars

    Science.gov (United States)

    Lalla, E. A.; Sanz-Arranz, A.; Lopez-Reyes, G.; Sansano, A.; Medina, J.; Schmanke, D.; Klingelhoefer, G.; Rodríguez-Losada, J. A.; Martínez-Frías, J.; Rull, F.

    2016-06-01

    The outcrop of "Los Azulejos" is visible at the interior of the Cañadas Caldera in Tenerife Island (Spain). It exhibits a great variety of alteration processes that could be considered as terrestrial analogue for several geological processes on Mars. This outcrop is particularly interesting due to the content of clays, zeolite, iron oxides, and sulfates corresponding to a hydrothermal alteration catalogued as "Azulejos" type alteration. A detailed analysis by portable and laboratory Raman systems as well as other different techniques such as X-ray diffraction (XRD) and Mössbauer spectroscopy has been carried out (using twin-instruments from Martian lander missions: Mössbauer spectrometer MIMOS-II from the NASA-MER mission of 2001 and the XRD diffractometer from the NASA-MSL Curiosity mission of 2012). The mineral identification presents the following mineral species: magnetite, goethite, hematite, anatase, rutile, quartz, gregoryite, sulfate (thenardite and hexahydrite), diopside, feldspar, analcime, kaolinite and muscovite. Moreover, the in-situ Raman and Micro-Raman measurements have been performed in order to compare the capabilities of the portable system specially focused for the next ESA Exo-Mars mission. The mineral detection confirms the sub-aerial alteration on the surface and the hydrothermal processes by the volcanic fluid circulations in the fresh part. Therefore, the secondary more abundant mineralization acts as the color agent of the rocks. Thus, the zeolite-illite group is the responsible for the bluish coloration, as well as the feldspars and carbonates for the whitish and the iron oxide for the redish parts. The XRD system was capable to detect a minor proportion of pyroxene, which is not visible by Raman and Mössbauer spectroscopy due to the "Azulejos" alteration of the parent material on the outcrop. On the other hand, Mössbauer spectroscopy was capable of detecting different types of iron-oxides (Fe3+/2+-oxide phases). These analyses

  16. Chemical mobility during low-grade metamorphism of a Jurassic lava flow: Río Grande Formation, Peru

    Science.gov (United States)

    Aguirre, L.

    Chemical and mineralogical changes produced by very low-grade metamorphism in a 40 meter thick, K-rich, calc-alkaline andesite flow of the marine Jurassic Río Grande Formation of southern coastal Peru are discussed. This metamorphism (=spilitization) was non-deformational and generated spilitic domains at (and near) both vesicular margins of the flow, whereas the massive central zone remained relatively unaltered. The metadomains are characterized by mineral associations of the zeolite facies. Primary minerals are Ca-plagioclase, augitic pyroxene, iron-titanium oxides, and (pseudomorphs after) olivine. Metamorphic minerals are: albite (three generations), K-feldspar, pumpellyite, chlorite, interlayered chlorite-celadonite, celadonite, various mixed-layer Si- and Fe-rich phyllosilicates, "iddingsite," calcite, analcime, titanite, and white mica. The effect of the metamorphism on the rock chemistry is reflected in changes especially observed at the marginal zones of the flow which affect major, trace, and RE elements: 1) strong increase of the iron oxidation ratio (Fe 2O 3/FeO); 2) enrichment in Na 2O accompanied by a concomitant depletion of CaO in non-amygdaloidal domains; 3) depletion of SiO 2; 4) strong enrichment in H 2O and CO 2; 5) marked depletion of Sr and Rb; 6) enrichment in Cl and S; and 7) slight depletion in RE elements, notably in the top zone of the flow. Conversely, elements such as Ti, P, Nb, and Y were fairly immobile, whereas Zr and K were only slightly mobilized. The effect of the metamorphism on the mineral chemistry is expressed by the predominance of metastable equilibrium evidenced by the existence of wide compositional ranges in the phyllosilicates, the incomplete albitization of the Ca-plagioclase, and the Al-rich character of the pumpellyites. The metamorphism is considered to be of hydrothermal-burial type, which takes place at low temperature and pressure — probably about 125-230°C and less than 3 kb, and is produced mainly through

  17. Basaltic Martian analogues from the Baikal Rift Zone and Mongolian terranes

    Science.gov (United States)

    Gurgurewicz, J.; Kostylew, J.

    2007-08-01

    these results with those of Martian missions. The range of the recorded spectra is from 400 to 2000 cm-1. Characteristic absorption bands in the spectra confirm the presence of minerals observed in thin sections and moreover, indicate the presence of leucite, analcime and saponite. The analyzed spectra have been compared with those of the Planetary Fourier Spectrometer of the Mars Express mission. The long wavelength channel of this spectrometer has a similar spectral range, from 230 to 2000 cm-1. This comparison indicates the similar absorption bands of clinopyroxenes in both spectra. References: [1] Komatsu G. (2003) Lunar Planet. Sci. XXXIV, abstract 1314. [2] Soja C. M. and White B. (2006) Geol. Soc. Amer., 38, 90. [3] Parfenov L. M. et al. (2002) Northeast Asia geodynamics map.

  18. Natural zeolites filling amygdales and veins in basalts from the British Tertiary Igneous Province on the Isle of Skye, Scotland

    Directory of Open Access Journals (Sweden)

    Triana J M

    2012-10-01

    Full Text Available

    ABSTRACT

    Natural zeolites filling amygdales and veins in tertiary basaltic host rocks on the Isle of Skye (NW Scotland have been studied in some detail by transmitted light microscopy, scanning electron microscopy and X-ray diffraction techniques . The zeolites and associated minerals so identified in order of their relative time of formation from early to late were nontronite, amorphous silica phases, carbonate phases, chabazite, phillipsite, wairakite, thomsonite, analcime, natrolite and stilbite-type minerals . Zeolite formation in the Skye basalts began with low Si/Al ratio Na zeolites and a gradual increase in Ca content and Si/Al ratio, ending up as Ca zeolites . They were probably formed as a consequence of late-stage hydrothermal activity, although, locally, contact metamorphism may control the process of zeolite formation

    RESUMEN

    Las zeolitas naturales como relleno en amígdalas y venas que ocurren en rocas basálticas Terciarias de la Isla de Skye (NW Escocia han sido estudiadas en detalle por técnicas de microscopía de luz transmitida, microscopía electrónica de barrido y difracción de rayos X. Las zeolitas y los minerales asociados identificados, en orden de su tiempo relativo de formación, son nontronita, fases de sílice amorfa, carbonatos, chabazita, filipsita, wairakita, thomsonita, analcima, natrolita y minerales tipo estilbita. La formación de zeolitas en los basaltos de Skye comenzó con una zeolita rica en Na de baja relación Si/Al y con el aumento gradual en el contenido de Ca y Si/Al, terminó con una zeolita rica en Ca Estas probablemente se formaron como consecuencia de una actividad hidrotermal tardía, aunque localmente un metamorfismo de contacto pudo controlar el proceso de formación de las zeolitas

  19. Composition and diagenetic processes of sandstone and tuff deposits of the Cenomanian Cardiel Formation, Cardiel Lake area, province of Santa Cruz

    Directory of Open Access Journals (Sweden)

    R.R. Andreis

    2007-06-01

    Full Text Available The Cardiel Formation (Cenomanian, around 200 m in thickness in the studied area, includes different types of volcaniclastic deposits, mainly represented by fine tuffs and massive bentonites, and subordinated epiclastics such as lithic sandstones of yellowish-brown, dusky yellow, or light olive hues, siltstones and claystones. Reddened paleosols with some small axial roots and weak prismatic structures appear on top of siltstones, tuffs and bentonites. Tufites and tuffs contain the same neovolcanic components, abundant glass shards and minor pumices. Different types of glass shards can be differentiated whitin this unit, whereas pumice fragments are represented by different vesicular varieties. Vitreous tuffaceous clasts are abundant in the tufites. Almost all samples contain not only diagenetically-derived, but also pedogenetically-infiltrated montmorillonite, as well as zeolites. Predominant Ca-Na-K clinoptilolite (Si/Al>4 and minor analcime (Si/Al near 3 were identified. Smectite and clinoptilolite may either replace glass-shards or pumices, or fill pore spaces, whereas smectite also appears as thin cutans. The sequence of diagenetic processes includes the conversion (hydrolysis of glass to smectite, and later to zeolites. Furthermore, zeolites preceded calcite growth (sometimes replacing glass-shards or pumices, which in turn, formed prior to pervading ferric oxides-hydroxides. The vertical distribution of zeolites can be explained taking into account the presence of percolating waters in an open hydrologic system. The zeolite content throughout the whole profile links the mineralogical association observed within the sediments of the Cardiel Formation to the clinoptilolite zone. Paleoenvironmental reconstructions for the Cardiel Formation point out to tidal currents taking place in wide lagoons; tuffaceous and bentonitic deposits covered those ancient lagoons forming wide, flat plains on which paleosols developed. Paleocurrents measured on

  20. Petrologic and isotopic data from the Cretaceous (Campanian) Blackhawk Formation and Star Point Sandstone (Mesaverde Group), Wasatch Plateau, Utah

    Science.gov (United States)

    Fishman, Neil S.; Turner, Christine E.; Peterson, Fred

    2013-01-01

    The presence of discrete minerals associated with coal—whether (1) detrital or authigenic constituents of the coals or in thin mudstone or siltstone units interbedded with coals, or (2) authigenic phases that formed along cleats—might influence its utilization as an energy resource. The build-up of sintered ash deposits on the surfaces of heat exchangers in coal-fired power plants, due to the alteration of minerals during combustion of the coal, can seriously affect the functioning of the boiler and enhance corrosion of combustion equipment. In particular, the presence of sodium in coals has been considered a key factor in the fouling of boilers; however, other elements (such as calcium or magnesium) and the amount of discrete minerals burned with coal can also play a significant role in the inefficiency of and damage to boilers. Previous studies of the quality of coals in the Cretaceous (Campanian) Blackhawk Formation of the Wasatch Plateau, Utah, revealed that the sodium content of the coals varied across the region. To better understand the origin and distribution of sodium in these coals, petrologic studies were undertaken within a sedimentological framework to evaluate the timing and geochemical constraints on the emplacement of sodium-bearing minerals, particularly analcime, which previously had been identified in coals in the Blackhawk Formation. Further, the study was broadened to include not just coals in the Blackhawk Formation from various localities across the Wasatch Plateau, but also sandstones interbedded with the coals as well as sandstones in the underlying Star Point Sandstone. The alteration history of the sandstones in both formations was considered a key component of this study because it records the nature and timing of fluids passing through them and the associated precipitation of sodium-bearing minerals; thus, the alteration history could place constraints on the distribution and timing of sodium mineralization in the interbedded or

  1. Thermodynamic and Kinetic Aspects of the Dissolution of Quartz-Kaolinite Mixtures by Alkalis Aspects thermodynamiques et cinétiques de la dissolution des mélanges quartz-kaolinite par les alcalis

    Directory of Open Access Journals (Sweden)

    Labrid J.

    2006-11-01

    de réduire la tension interfaciale entre l'eau et l'huile brute, grâce à la formation in situ de tensio-actifs résultant de la réaction de l'additif alcalin avec certains constituants de l'huile. La technique s'est depuis largement améliorée avec l'emploi des alcalins en combinaison avec d'autres additifs chimiques tels que les polymères et les tensio-actifs. Dans tous les cas, un point critique réside dans le transport de l'agent alcalin du puits d'injection au puits de production. Divers processus contribuent en effet à réduire la quantité d'additif réellement disponible. Parmi ceux-ci, figure la consommation de l'alcali par dissolution de certains minéraux de la roche réservoir. Ce problème est abordé en étudiant tout d'abord les conditions de dissolution d'un sable supposé représenter la matrice quartzeuse d'une roche gréseuse naturelle. Nous avons adopté un schéma cinétique fondé sur l'adsorption d'acide silicique à la surface du quartz : l'étape déterminante de la dissolution est l'expulsion d'un motif silicique du réseau cristallin, l'acide silicique adsorbé bloquant la dissolution. La concentration en silicium solubilisé au cours du temps est calculée à l'aide d'un modèle numérique qui utilise les paramètres cinétiques déterminés de manière expérimentale. Il est connu que l'adsorption d'aluminium à la surface du quartz réduit de manière considérable sa dissolution. Dans une roche gréseuse, l'aluminium provient de la dissolution des argiles et des feldspaths. Les essais de dissolution effectués avec des solutions alcalines contenant de l'aluminium ont montré que celui-ci s'adsorbait à la surface solide et réduisait ainsi les vitesses initiale et courante de dissolution. Ces essais ont aussi permis de mettre en évidence la formation et la précipitation, au cours de la dissolution, d'un aluminosilicate : l'analcime AISi2O6Na. H2O. Son produit de solubilité a pu être déterminé par analyse des effluents. L

  2. Identification of Some Zeolite Group Minerals by Application of Artificial Neural Network and Decision Tree Algorithm Based on SEM-EDS Data

    Science.gov (United States)

    Akkaş, Efe; Evren Çubukçu, H.; Akin, Lutfiye; Erkut, Volkan; Yurdakul, Yasin; Karayigit, Ali Ihsan

    2016-04-01

    Identification of zeolite group minerals is complicated due to their similar chemical formulas and habits. Although the morphologies of various zeolite crystals can be recognized under Scanning Electron Microscope (SEM), it is relatively more challenging and problematic process to identify zeolites using their mineral chemical data. SEMs integrated with energy dispersive X-ray spectrometers (EDS) provide fast and reliable chemical data of minerals. However, considering elemental similarities of characteristic chemical formulae of zeolite species (e.g. Clinoptilolite ((Na,K,Ca)2 -3Al3(Al,Si)2Si13O3612H2O) and Erionite ((Na2,K2,Ca)2Al4Si14O36ṡ15H2O)) EDS data alone does not seem to be sufficient for correct identification. Furthermore, the physical properties of the specimen (e.g. roughness, electrical conductivity) and the applied analytical conditions (e.g. accelerating voltage, beam current, spot size) of the SEM-EDS should be uniform in order to obtain reliable elemental results of minerals having high alkali (Na, K) and H2O (approx. %14-18) contents. This study which was funded by The Scientific and Technological Research Council of Turkey (TUBITAK Project No: 113Y439), aims to construct a database as large as possible for various zeolite minerals and to develop a general prediction model for the identification of zeolite minerals using SEM-EDS data. For this purpose, an artificial neural network and rule based decision tree algorithm were employed. Throughout the analyses, a total of 1850 chemical data were collected from four distinct zeolite species, (Clinoptilolite-Heulandite, Erionite, Analcime and Mordenite) observed in various rocks (e.g. coals, pyroclastics). In order to obtain a representative training data set for each minerals, a selection procedure for reference mineral analyses was applied. During the selection procedure, SEM based crystal morphology data, XRD spectra and re-calculated cationic distribution, obtained by EDS have been used for the

  3. Isla Isabel (Nayarit, México): Quaternary alkalic basalts with mantle xenoliths erupted in the mouth of the Gulf of California

    Science.gov (United States)

    Housh, Todd B.; Aranda-Gómez, José Jorge; Luhr, James F.

    2010-11-01

    Isla Isabel is a small island (~ 1.06 km 2) off the coast of Nayarit where intraplate-type alkali-basaltic volcanic rocks erupted during the Quaternary, and one of two Mexican islands (along with Isla Guadalupe) where it is known that the alkali basalts have transported peridotite xenoliths to the surface. The volume of the island is estimated at approximately 4.2 km 3; the volume above sea level is estimated to be approximately 0.03 km 3. The dominant volcanic rock type exposed above sea level is analcime-cemented basaltic tuff-breccia, the rapidly lithified products of hydrovolcanic eruptions; however, subaerial scoria-fall deposits and lava flows are also present. Ten analyzed Isla Isabel volcanic rocks are relatively homogeneous alkali basalts with 4.5-6.4 wt.% nepheline in the CIPW norm. Compared to other analyzed Mexican intraplate-type volcanic rocks from oceanic and continental localities, at the same MgO content, the Isabel samples are depleted in TiO 2, FeO total, and Na 2O, and moderately incompatible trace elements (e.g., Sm, Eu, Tb, and Zr). On the other hand, they are enriched in CaO and Al 2O 3, and relatively compatible trace elements (e.g., Lu and Sc). It is suggested that relative to other Mexican intraplate alkaline lavas the Isabel lavas were derived by higher degrees of melting at lower pressures of mantle that is characterized by ancient HIMU-like isotope systematics. Isabel olivine phenocrysts and their spinel inclusions range to Mg#s that overlap with the peridotite minerals in the accompanying mantle xenoliths, which has not been reported at other Mexican xenolith localities. Olivine-hosted glass inclusions in rapidly quenched scoria yielded the first estimates for volatile contents in Mexican intraplate-type mafic melts; maximum values are: 1.3 wt.% H 2O, 2241 ppm CO 2, 1500 ppm F, 1300 ppm S, and 1200 ppm Cl. Isabel peridotites (Ol ± Hy ± Di + Sp ± Pl) include dunites, harzburgites, and rare plagioclase-harzburgite, and are depleted in

  4. Hypogene and supergene alteration of the zeolite-bearing pyroclastic deposits at Tell Rimah, Jordan, and rift-related processes along the Dead-Sea-Transform Fault System during the Quaternary

    Science.gov (United States)

    Dill, H. G.; Techmer, A.; Botz, R.; Dohrmann, R.; Kaufhold, S.

    2012-09-01

    The boundary between the Arabian and African plates, is marked in the Middle East by one of the most prominent deep-seated lineamentary structures, called the Dead-Sea-Transform Fault System (DSTFS). Structural and mineralogical processes related to the DSTFS were correlated with equivalent processes leading to the alteration of pyroclastic deposits of alkali-olivine basaltic to nepheline basaltic composition which formed during a time span of less than 0.5 Ma. The large deposit of Tell Rimah, Jordan, is operated for the exploitation of zeolites, tuffs, and as pozzolana raw material. Four discrete stages of mineralizations have been distinguished from each other within these volcanic-hosted mineral deposits. (1) Hypogene syneruptive alteration of pyroclastic rocks produced siliceous gels ("allophane"), smectite, analcime, and phillipsite in vesicles when the groundwater level was low in the rift basin of the DSTFS. The lake-level lowstand caused the fluid system in the pyroclastic cone to become self-sufficient and it has been considered as a closed hydrothermal system. (2) Periods of tectonic and magmatic quiescence grinded the detrital sedimentation in the rift basin to a halt, while triggering a supergene alteration in the eruptive cones on the adjacent Arabian Plate. (3) Epigenetic alteration affected the pyroclastic rocks in the distal part of the DSTFS as a result of a rising water level. The water gradually filled the pore space of the permeable pyroclastic deposits almost to completeness and caused meniscus and blocky cements of calcite, phillipsite and chabazite to develop. In the rift basin, contemporaneously with the alteration of the pyroclastic rocks, freshwater limestones formed on calcareous bedrocks. Ba and Mn minerals in these freshwater limestones were supplied by subaquatic brines. Subsequently, a drastic lowering of the lake water level in the DSTFS converted the system of subaquatic freshwater limestones into subaerial tufa and travertine. As

  5. Síntese de zeólitas a partir de cinza volante de caldeiras: caracterização física, química e mineralógica Synthesis of zeolites from boiler fly ash: physical, chemical and mineralogical characterization

    Directory of Open Access Journals (Sweden)

    C. A. F. Rocha Junior

    2012-03-01

    chemical, physical and mineralogical characterization methods were carried out: X-ray diffractometry, X-ray fluorescence, scanning electron microscopy, granulometric analysis, differential thermal and thermogravimetric analysis (DTA-TG. The analyses were carried out at the following conditions: 60, 100, 150 and 190 °C, Na2O/Al2O3 molar ratio of 5 and Si/Al molar ratio ranging from 2.12 to 15, and reaction time of 24 h. The results of the fly characterization demonstrate its enormous potential as raw material for the zeolite synthesis. SiO2 and Al2O3 represent more than 50% of its composition, mineralogical phases defined, low humidity content, low particle size (d90 < 10 µm, among others. Mineralogical analyses of the synthesized products showed the formation of some zeolite types, as follow: analcime, phillipsite, sodalite, zeolite P and tobermorite. The results show that the mixture fly ash-microsilica in these reaction conditions point to a promising material for zeolite synthesis.

  6. Hydrothermal Synthesis of Zeolite from Coal Class F Fly Ash. Influence of Temperature

    Directory of Open Access Journals (Sweden)

    Goñi, S.

    2010-06-01

    Full Text Available The influence of temperature of alkaline hydrothermal treatment on the conversion in zeolite of Spanish coal low calcium-fly ash (ASTM class F is presented in this work. Zeolite Na-P1 gismondine type (Na6Al6Si10O32.12H2O was formed at the temperature of 100ºC, which transformed in zeolite; analcime-C type (Na(Si2AlO6H2O and sodalite (1.08 Na2O.Al2O3.1.68SiO2.1.8H2O at 200ºC together with traces of tobermorite-11Å (Ca5(OH2Si6O16.4H2O. At this temperature the 100% of the fly ash reaction was allowed. An equivalent study was carried out in water as reference. The zeolite conversion of the fly ash was characterized by X ray diffraction (XRD, FT infrared (FTIR spectroscopy, surface area (BET-N2 and thermal analyses.

    En este trabajo se presenta el papel que juega la temperatura durante el tratamiento hidrotermal en medio alcalino para convertir una ceniza volante de bajo contenido en cal (clase F, según la norma ASTM en zeolita. Durante este tratamiento a la temperatura de 100ºC se forma Zeolita Na-P1 tipo gismondina (Na6Al6Si10O32.12H2O; al elevar la temperatura a 200ºC, dicha zeolita se transforma en zeolita Analcima C (Na(Si2AlO6H2O y en fase sodalita (1.08 Na2O.Al2O3.1.68SiO2.1.8H2O junto con trazas de tobermorita-11Å (Ca5(OH2Si6O16.4H2O. A esta temperatura y en estas condiciones se ha conseguido un 100% de reacción. Un estudio equivalente se ha llevado a cabo empleando agua como medio de referencia. La conversión de ceniza volante en zeolita se ha caracterizado mediante técnicas, como difracción de Rayos X (DRX, espectroscopia

  7. Geochemical Modeling of ILAW Lysimeter Water Extracts

    Energy Technology Data Exchange (ETDEWEB)

    Cantrell, Kirk J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2014-12-22

    Geochemical modeling results of water extracts from simulated immobilized low-activity waste (ILAW) glasses, placed in lysimeters for eight years suggest that the secondary phase reaction network developed using product consistency test (PCT) results at 90°C may need to be modified for field conditions. For sediment samples that had been collected from near the glass samples, the impact of glass corrosion could be readily observed based upon the pH of their water extracts. For unimpacted sediments the pH ranged from 7.88 to 8.11 with an average of 8.04. Sediments that had observable impacts from glass corrosion exhibited elevated pH values (as high as 9.97). For lysimeter sediment samples that appear to have been impacted by glass corrosion to the greatest extent, saturation indices determined for analcime, calcite, and chalcedony in the 1:1 water extracts were near equilibrium and were consistent with the secondary phase reaction network developed using PCT results at 90°C. Fe(OH)3(s) also appears to be essentially at equilibrium in extracts impacted by glass corrosion, but with a solubility product (log Ksp) that is approximately 2.13 units lower than that used in the secondary phase reaction network developed using PCT results at 90°C. The solubilities of TiO2(am) and ZrO2(am) also appear to be much lower than that assumed in the secondary phase reaction network developed using PCT results at 90°C. The extent that the solubility of TiO2(am) and ZrO2(am) were reduced relative to that assumed in the secondary phase reaction network developed using PCT results at 90°C could not be quantified because the concentrations of Ti and Zr in the extracts were below the estimated quantification limit. Gibbsite was consistently highly oversaturated in the extract while dawsonite was at or near equilibrium. This suggests that dawsonite might be a more suitable phase for the secondary phase reaction network

  8. Fluid-Ultramafic Rock Interaction and Formation of Jadeite Rocks%流体一超镁铁质岩相互作用与硬玉岩的形成

    Institute of Scientific and Technical Information of China (English)

    祁敏; 向华; 钟增球; 周汉文

    2011-01-01

    俯冲带中流体与岩石相互作用以及流体循环一直是地质学家关注的焦点之一.硬玉岩(翡翠)作为高档宝玉石材料,其成因一直备受关注.硬玉岩产于与俯冲带有关的蛇纹石化超镁铁质岩中,是俯冲带中流体与超镁铁岩相互作用的特殊产物.岩石组合、岩相学、显微结构及矿物化学特征表明:橄榄岩与流体的作用可以分为5个阶段,分别为蛇纹石化→(绿泥石、金云母)→角闪石→辉石→(方沸石、钠长石)阶段.结合热力学相图,总结了橄榄岩与流体作用过程中矿物的演化序列.硬玉岩的形成需要富Na、Al、si流体和较高的压力.缅甸硬玉岩中,钠质闪石总是与硬玉岩伴生,钠质闪石成分变化大,且能与流体发生再平衡从而调节自身和流体的成分.钠质闪石在硬玉形成过程中充当了Na、Al、Si的缓冲剂,使Na、Al、Si达到一定比例有利于硬玉的结晶.%The fluid-rock interactions and fluid circulations in subduction zone have been a focus for geologists. As a kind of high-grade gem material, the genesis of jadeite rocks attracts an increasing concern. The jadeite rocks generally occur in the serpentinized ultramafic rocks in subduction zones and its formation is related to the interaction between subduction-related fluids and ultramafic rocks (peridotite). Based on rock association, petrography, microstructure and mineral chemical characteristics, the processes of interaction between peridotite and fluid can be divided into five stages, that is, serpentine→ (chlorite, phlogopite) →amphibole→pyroxene→ (analcime, albite). Combined with analysis of thermodynamic phase diagrams, the evolutionary series of minerals in the processes of interaction are identified. Formation of jadeite requires the fluids enrich in Na, Al, Si and under relatively higher pressure. In the jadeite rocks from Myanmar, the sodium amphiboles with various chemical components are always associated with

  9. 准噶尔盆地西北缘下二叠统油气储层中火山物质蚀变及控制因素%Alteration of volcanics and its controlling factors in the Lower Permian reservoirs at northwestern margin of Junggar Basin

    Institute of Scientific and Technical Information of China (English)

    朱世发; 朱筱敏; 吴冬; 刘英辉; 李盼盼; 姜淑贤; 刘学超

    2014-01-01

    通过岩心分析、显微镜下观察(常规、铸体薄片和扫描电镜)、岩石地球化学分析测试等技术手段,以准噶尔盆地西北缘下二叠统油气储层为实例,研究了火山岩、火山碎屑岩和火山岩屑质砂砾岩中的火山玻璃、火山碎屑、长石以及辉石、角闪石等火山物质的低温-埋藏蚀变作用。镜下观察发现,在含火山物质油气储层中,常见对储集空间具有重要影响的自生矿物主要有绿泥石、沸石(包括方沸石、片沸石和浊沸石)、方解石、钠长石和自生的石英。结合共生关系、元素组成和元素迁移,分析了自生矿物的微观特征和成因,建立了火山物质蚀变的成岩演化序列,可以概括为:①火山玻璃水化-蒙脱石化-沸石化及各种沸石的转化---钠长石化;②铁镁矿物影响的绿泥石化;③长石蚀变向绿泥石和方解石转化,后期发生钠长石化。在研究区,火山物质的蚀变和自生矿物的析出与中-基性的母岩物质组成密切相关,并受地层温度、压力、孔隙水的化学性质控制。研究火山物质蚀变的产物、蚀变过程及控制因素,能够明确含火山物质的油气储层质量差异机理,为优质储层预测提供科学的依据。%Based on observations of available cores ,thin-sections and SEM and analysis of rock geochemistry ,we studied low-temperature-burial metamorphism ( alteration ) of volcanics in the Lower Permian at northwestern margin of Junggar Basin .These volcanics include volcanic glass , volcanic clasts , feldspar , and mafic minerals such as pyroxene and horn-blende,etc.,which originate from lavas,pyroclastic rocks,and volcaniclastic sandstones or conglomerates .In oil/gas reservoirs containing volcanics ,the authigenic minerals that are common but important to pore spaces include chlorite ,ze-olites(like analcime,heulandite,and laumontite),calcite,albite,and authigenic quartz.Based on

  10. Composition and diagenetic processes of sandstone and tuff deposits of the Cenomanian Cardiel Formation, Cardiel Lake area, province of Santa Cruz Composición y procesos diagenéticos de los depósitos de arenisca y toba de la Formación Cardiel (Cenomaniano, área Lago Cardiel, provincia de Santa Cruz

    Directory of Open Access Journals (Sweden)

    R.R. Andreis

    2007-06-01

    Full Text Available The Cardiel Formation (Cenomanian, around 200 m in thickness in the studied area, includes different types of volcaniclastic deposits, mainly represented by fine tuffs and massive bentonites, and subordinated epiclastics such as lithic sandstones of yellowish-brown, dusky yellow, or light olive hues, siltstones and claystones. Reddened paleosols with some small axial roots and weak prismatic structures appear on top of siltstones, tuffs and bentonites. Tufites and tuffs contain the same neovolcanic components, abundant glass shards and minor pumices. Different types of glass shards can be differentiated whitin this unit, whereas pumice fragments are represented by different vesicular varieties. Vitreous tuffaceous clasts are abundant in the tufites. Almost all samples contain not only diagenetically-derived, but also pedogenetically-infiltrated montmorillonite, as well as zeolites. Predominant Ca-Na-K clinoptilolite (Si/Al>4 and minor analcime (Si/Al near 3 were identified. Smectite and clinoptilolite may either replace glass-shards or pumices, or fill pore spaces, whereas smectite also appears as thin cutans. The sequence of diagenetic processes includes the conversion (hydrolysis of glass to smectite, and later to zeolites. Furthermore, zeolites preceded calcite growth (sometimes replacing glass-shards or pumices, which in turn, formed prior to pervading ferric oxides-hydroxides. The vertical distribution of zeolites can be explained taking into account the presence of percolating waters in an open hydrologic system. The zeolite content throughout the whole profile links the mineralogical association observed within the sediments of the Cardiel Formation to the clinoptilolite zone. Paleoenvironmental reconstructions for the Cardiel Formation point out to tidal currents taking place in wide lagoons; tuffaceous and bentonitic deposits covered those ancient lagoons forming wide, flat plains on which paleosols developed. Paleocurrents measured on

  11. Long-Term CO2 Exposure Experiments - Geochemical Effects on Brine-Saturated Reservoir Sandstone

    Science.gov (United States)

    Fischer, Sebastian; Zemke, Kornelia; Liebscher, Axel; Wandrey, Maren

    2010-05-01

    The injection of CO2 into deep saline aquifers is the most promising strategy for the reduction of CO2 emissions to the atmosphere via long-term geological storage. The study is part of the CO2SINK project conducted at Ketzin, situated 40 km west of Berlin. There, food grade CO2 has been pumped into the Upper Triassic Stuttgart Formation since June 2008. The main objective of the experimental program is to investigate the effects of long-term CO2 exposure on the physico-chemical properties of the reservoir rock. To achieve this goal, core samples from observation well Ktzi 202 have been saturated with synthetic brine and exposed to CO2 in high quality steel autoclaves at simulated reservoir P-T-conditions of 5.5 MPa and 40 ° C. The synthetic brine had a composition representative of the formation fluid (Förster et al., 2006) of 172.8 g/l NaCl, 8.0 g/l MgCl2×2H2O, 4.8 g/l CaCl2×2H2O and 0.6 g/l KCl. After 15 months, the first set of CO2-exposed samples was removed from the pressure vessels. Thin sections, XRD, SEM as well as EMP data were used to determine the mineralogical features of the reservoir rocks before and after the experiments. Additionally, NMR relaxation and MP was performed to measure poroperm and pore size distribution values of the twin samples. The analyzed samples are fine- to medium grained, moderately well- to well sorted and weakly consolidated sandstones. Quartz and plagioclase are the major components, while K-feldspar, hematite, white & dark mica, chlorite and illite are present in minor and varying amounts. Cements are composed of analcime, dolomite and anhydrite. Some samples show mm- to cm-scale cross-beddings. The laminae comprise lighter, quartz- and feldspar-dominated layers and dark-brownish layers with notably less quartz and feldspars. The results are consistent with those of Blaschke et al. (2008). The plagioclase composition indicates preferred dissolution of the Ca-component and a trend toward albite-rich phases or even pure

  12. Selected durability studies of geopolymer concrete with respect to carbonation, elevated temperature, and microbial induced corrosion

    Science.gov (United States)

    Badar, Mohammad Sufian

    prepared with certain fly ashes exhibited signs of expansion along with cracking and spalling, while GPC prepared with specific class F fly ash showed superior resistance to thermal shock. Microstructural analysis revealed that the resistance of GPC at elevated temperatures was dependent on the type of fly ash used, its particle size distribution, formation of zeolitic phases such as sodalite, analcime and nepheline, and the overall pore structure of the geopolymer concrete. The work indicates that the chemical composition and particle size distribution of the fly ash, type of fly ash (Class C & F) and the geopolymerization process that took place a vital role in the performance of geopolymer concretes in high temperature applications. Microbial Induced Corrosion: Corrosion is a major form of deterioration in concrete structures. According to a report published by the U.S. FHWA 2002, the cost of corrosion in water and wastewater conveyance, and storage and treatment facilities in the U.S. is about $138 billions. A main form of corrosion in wastewater collection systems is Microbial Induced Corrosion (MIC). However, the conditions present in industrial or municipal wastewater pipes, or storage facility are induced by the production of sulfuric acid by biological processes, which cannot be fully mimicked by simple acid corrosion. The present study intends to provide similar conditions inside pipe specimens that mimic a true sewer atmosphere. The experimental setup consisted of three 12" diameter and 30" long concrete pipe specimens, 2 specimens were coated with different formulations of GPC while the third was a control. Both ends of each pipe specimen were sealed to prevent hydrogen sulfide gas from escaping. One pipe was coated with GPC that had a biocide agent entrained. Another pipe specimen was coated with OPC and the 3rd pipe was used as a control and was not coated. Parameters measured can be divided into three groups: general environmental parameters like pH and

  13. Encapsulating Metal Clusters and Acid Sites within Small Voids: Synthetic Strategies and Catalytic Consequences

    Science.gov (United States)

    Goel, Sarika

    The selective encapsulation of metal clusters within zeolites can be used to prepare clusters that are uniform in diameter and to protect them against sintering and contact with feed impurities, while concurrently allowing active sites to select reactants based on their molecular size, thus conferring enzyme-like specificity to chemical catalysis. The apertures in small and medium-pore zeolites preclude the use of post-synthetic protocols to encapsulate the relevant metal precursors because cationic or anionic precursors with their charge-balancing double layer and gaseous complexes cannot diffuse through their windows or channels. We have developed general strategies to encapsulate metal clusters within small-pore zeolites by using metal precursors stabilized by ammonia or organic amine ligands, which stabilize metal precursors against their premature precipitation at the high temperature and pH conditions required for the hydrothermal synthesis of the target zeolite structures and favor interactions between metal precursors and incipient aluminosilicate nuclei during the self-assembly of microporous frameworks. When synthesis temperatures were higher than 400 K, available ligands were unable to prevent the premature precipitation of the metal precursors. In such cases, encapsulation was achieved instead via interzeolite transformations after successfully encapsulating metal precursors or clusters via post-synthesis exchange or ligand protection into parent zeolites and subsequently converting them into the target structures while retaining the encapsulated clusters or precursors. Such strategies led to the successful selective encapsulation of a wide range of metal clusters (Pt, Pd, Ru, Rh, Ir, Re, and Ag) within small-pore (SOD (sodalite), LTA (Linde type A (zeolite A)), GIS (gismondine), and ANA (analcime)) and medium-pore (MFI (ZSM-5)) zeolites. These protocols provide novel and diverse mechanism-based strategies for the design of catalysts with protected