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Sample records for spodumene petalite eucryptite

  1. Luminescence study of spodumene

    International Nuclear Information System (INIS)

    Isotani, S.; Fujii, A.T.; Antonini, R.; Pontuschka, W.M.; Rabani, S.R.; Furtado, W.W.

    1990-02-01

    A comparative study is made of the luminescence of five kinds of spodumene from Minas Gerais, Brazil, studied previously by optical absorption spectroscopy. Natural gemstones are used which, in the course of the experiments, were irradiated with X-rays. (L.C.) [pt

  2. Extraction of lithium Carbonate from Petalite Ore (Momeik District, Myanmar)

    International Nuclear Information System (INIS)

    Tun Tun Moe

    2011-12-01

    The methods for preparing high purity lithium carbonate which can be used for pharmaceutical applications, electronic grade crystals of lithium or to prepare battery-grade lithium metal are disclosed. Lithium carbonate as commercially produced from mineral extraction, lithium containing brines or sea water. One method for the production of pure lithium carbonate from mineral source (petalite ore) obtained from Momeik District, Myanmar is disclosed. Method for mineral processing of ore concentrate is also disclosed.

  3. Fluorescence and optical absorption in spodumene

    International Nuclear Information System (INIS)

    Antonini, R.

    1987-01-01

    This work studied the mechanism of the isothermal decay's kinetic of the 15.600 cm-1 optical absorption band (A.O.) of irradiated spodumene, and the phosphorescence of irradiated spodumene in low temperatures. The kinetic mechanisms applying the bimolecular model to liberation, capture and recombination reactions are analysed. The coupled differential equations, resultants of this model, numerically using the Runge-Kutta method is solved, and a computer programs that allowed determine the kinetics parameters by try and error methods is developped. This work showed that the electrons are untrapped according to Arrhernios kinetic and that the parameters of the trap and recombination are proportional to a factor (√T - √T o ), where T o is the cutting temperature, bfore which the reactions do not occur. (author) [pt

  4. Time measurements for thermalequilibrium in spodumene crystals

    International Nuclear Information System (INIS)

    Fujii, A.T.; Isotani, S.

    1982-01-01

    Experiments for measurement of time taken to reach thermal equilibrium in Spodumene crystals - 2mm to 5,4mm thick - in the temperature range 100 0 to 250 0 C are described. The measurements indicate a linear relationship between time and thickenes for heating as well as for cooling. Difference in thermal equilibrium time for heating and for cooling is about of 20 seconds. (author) [pt

  5. Crystallization and properties of a spodumene-willemite glass ceramic

    International Nuclear Information System (INIS)

    Hu, A.M.; Li, M.; Dali, D.L. Mao; Liang, K.M.

    2005-01-01

    Spodumene-willemite glass ceramics were produced by replacement of Al 2 O 3 in lithium aluminium silicate by ZnO. With replacement of Al 2 O 3 by ZnO, the batch melting temperature, glass transition temperature (T g ) and crystallization temperature (T p ) all decreased. The main crystalline phases precipitated were eucriptite, β-spodumene and willemite (Zn 2 SiO 4 ). All compositions of glass ceramics showed bulk crystallization. As ZnO content increased, the grain sizes and thermal expansion coefficients increased, while the flexural strength and fracture toughness of the glass-ceramics increased first, and then decreased. The mechanical properties were correlated with crystallization and morphology of glass ceramics

  6. Radiation detection using the color changes of lilac spodumene

    International Nuclear Information System (INIS)

    Oliveira, Raquel A.P.; Mello, Ana Carolina S.; Lima, Hestia R.B.R.; Campos, Simara Santos; Souza, Suzana O.

    2009-01-01

    The use of radiation in industrial processes currently offers several advantages in the field of sterilization of medical and pharmaceuticals products, the preservation of food, and a variety of other products widely used in modern society. A dosimetry of confidence is a key parameter for the quality assurance of radiation processing and the irradiated products. This work investigates dosimetric properties in natural spodumene, LiAlSi 2 O 6 , called kunzite, from Minas Gerais State, Brazil. After X irradiation on the samples in powder form was detected a change in color of the crystal where the dose received. This makes a possible viability of this material is applied in research on development of radiation detectors using the change in color of purple spodumene. (author)

  7. Luminescence spectra of lead tungstate, spodumene and topaz crystals

    International Nuclear Information System (INIS)

    Ramachandran, Vasuki

    2002-01-01

    A detailed set of thermoluminescence, cathodoluminescence and radioluminescence (TL, CLTL and RLTL) data of lead tungstate, Spodumene and Topaz have been reported for the first time over a wide temperature range from 25 to 500K. Lead tungstate (PbWO 4 ), a widely known scintillating material, gives TL glow peaks which are related to complex defect centres. Doping of this crystal with trivalent rare earth ions (La 3+ , Y 3+ ) reduces the slow component of the emission thereby making it more suitable for its applications. The pentavalent dopants on the other hand, enhance the green emission and quench the blue emission at temperatures 100K. The origin and the irradiation temperature definitely have an effect on the spectrum. No strong relationship could be derived from the dose dependence data. Two less studied minerals, Spodumene and Topaz have also been investigated with the luminescence techniques. The glow peak near 250degC is thought to have originated from Mn 2+ centres. As there are no ESR data available, the assignment of defect centres is rather difficult. Cr + acts as the quencher in green spodumene. Topaz had the same treatment as the other two sets of samples and the defect centre characterisation looks complex as each coloured sample gave different patterns of glow peaks. Cathodoluminescence whilst heating (CLTL) of all these samples showed some unusual features in the form of a luminescence intensity step which is believed to have originated from the presence of ice. Water, in nanoparticle size quantities, is present as a contaminant in the lattice and undergoes a phase transition at 170K from hexagonal to cubic structures. This phase change influences the luminescence efficiency of the host material and is reflected in the spectrum as a discontinuity in intensity. (author)

  8. In situ synchrotron XRD analysis of the kinetics of spodumene phase transitions.

    Science.gov (United States)

    L Moore, Radhika; Mann, Jason P; Montoya, Alejandro; Haynes, Brian S

    2018-04-25

    The phase transition by thermal activation of natural α-spodumene was followed by in situ synchrotron XRD in the temperature range 896 to 940 °C. We observed both β- and γ-spodumene as primary products in approximately equal proportions. The rate of the α-spodumene inversion is first order and highly sensitive to temperature (apparent activation energy ∼800 kJ mol-1). The γ-spodumene product is itself metastable, forming β-spodumene, with the total product mass fraction ratio fγ/fβ decreasing as the conversion of α-spodumene continues. We found the relationship between the product yields and the degree of conversion of α-spodumene to be the same at all temperatures in the range studied. A model incorporating first order kinetics of the α- and γ-phase inversions with invariant rate constant ratio describes the results accurately. Theoretical phonon analysis of the three phases indicates that the γ phase contains crystallographic instabilities, whilst the α and β phases do not.

  9. Optical absorption study of radiation and thermal effects in Brazilian samples of spodumene

    International Nuclear Information System (INIS)

    Isotani, S.; Fujii, A.T.; Antonini, R.; Furtado, W.

    1988-03-01

    A detailed analysis of the optical absorption spectra of five varieties of Brazilian spodumene is presented. The samples were submitted to heat treatments and irradiated with gamma rays, x radiation, electrons and ultraviolet light. (M.C.K.) [pt

  10. Comparative study of five varieties of spodumene through optical absorption

    International Nuclear Information System (INIS)

    Fujii, A.T.; Isotani, S.

    1983-11-01

    A comparative study of five varieties of spodumene crystals from Brazil through optical absorption spectroscopy, classified according to the colours lylac, colourless I, colourless II, yellow and green is reported. This series shows a consistent increase of the [Fe]/[Mn] ratio. The principal bands in the yellow sample are at 7,000 and 9,000 cm -1 , and in the green sample besides these bands a band at 16,000 cm -1 is observed. In lylac, colourless I and colourless II samples, the principal bands are at 18,000 cm -1 and when irradiated two new bands appears at 15,700 cm -1 (E perpendicular to c) and 11,000 cm -1 (K perpendicular to c). It is suggested that in green and yellow samples the bands are due to Fe 2+ (at 7,000 cm -1 and 9,000 cm -1 ) and due to Fe 2+ - Fe 3+ charge transfer (at 16,000 cm -1 ). In lylac and colourless I samples the model for Mn 3+ at two different sites is applied. The colourless II corresponds to the case in which Mn 3+ is at one site alone, being prohibited from occupying the second site due to higher Fe concentration. (Author) [pt

  11. Influence of the amount containing spodumene or albite on the sintering of a triaxial ceramic

    International Nuclear Information System (INIS)

    Oliveira, Camila Felippe de; Strecker, Kurt

    2012-01-01

    In this study, we investigated the properties of porcelain stoneware, made with albite or spodumene. The amount of the feldspar in the compositions ranged from 15 to 30% by weight. Specimens were pressed and sintered at 1000, 1100, 1200 and 1280 °C with an isotherm of 1 hour at the maximum temperature. The samples were characterized by analysis of the fracture surface using scanning electron microscopy and the vitrification curves, showing both the linear shrinkage and porosity in relation to the sintering temperature. The best results were obtained for samples containing 30% spodumene sintered at 1280 °C, with a linear shrinkage of 9.97% and porosity of 13.28%, while the corresponding results of samples containing 30% albite were 10.13% and 12.17%, respectively. It is concluded that the use of spodumene in the production of porcelain stoneware is viable, resulting in comparable properties. (author)

  12. Preliminary evaluation of beta-spodumene as a fusion reactor structural material

    International Nuclear Information System (INIS)

    Kelsey, P.V. Jr.; Schmunk, R.E.; Henslee, S.P.

    1982-01-01

    Beta-spodumene was investigated as a candidate material for use in fusion reactor environments. Properties which support the use of beta-spodumene include good thermal shock resistance, a very low coefficient of thermal expansion, a low-Z composition which would result in minimum impact on the plasma, and flexibility in fabrication processes. Specimens were irradiated in the Advanced Test Reactor (ATR) to a fluence of 5.3 x 10 22 n/m 2 , E > MeV, and 4.9 x 10 23 n/m 2 thermal fluence in order to obtain a preliminary evaluation of the impact of irradiation on the material. Preliminary data indicate that the mechanical properties of beta-spodumene are little affected by irradiation. Gas production and release have also been investigated. (orig.)

  13. Spectrophotometric study of bio-sorption of uranium on glass grade spodumene shell powder

    International Nuclear Information System (INIS)

    Parakudyil, A.S.; Pillai, A.K.; Reddy, A.V.R.; Singal, R.K.; Sharma, P.K.; Michael, K.M.

    2012-01-01

    Separation of uranium found in iron ore leachates was done by extraction chromatography using glass grade spodumene shellpowder (GSS) in nitric acid medium and analyzed spectrophotometrically. The influences of metal ion concentration, pH and adsorption capacity of biomass were investigated. Biosorption is a potential method of separation of heavy and trace metals from waste water and effluents from various sources. The adsorption capacities of biomass were investigated by batch experiments and column experiments. In the present study, glass grade spodumene shell powder (GSS) in acidic medium is being used as a biosorbent

  14. Anisotropic thermal expansion behaviors of copper matrix in β-eucryptite/copper composite

    International Nuclear Information System (INIS)

    Wang Lidong; Xue Zongwei; Qiao Yingjie; Fei, W.D.

    2012-01-01

    Highlights: ► The thermal expansion behaviors of Cu matrix were studied by in situ XRD. ► The expansion of Cu{1 1 1} plane is linear, that of Cu{2 0 0} is nonlinear. ► The anisotropic thermal expansion of Cu is related to the twinning of Cu matrix. ► The twinning of Cu matrix makes the CTE of the composite increasing. - Abstract: A β-eucryptite/copper composite was fabricated by spark plasma sintering process. The thermal expansion behaviors of Cu matrix of the composite were studied by in situ X-ray diffraction during heating process. The results show that Cu matrix exhibits anisotropic thermal expansion behaviors for different crystallographic directions, the expansion of Cu{1 1 1} plane is linear in the temperature range from 20 °C to 300 °C and the expansion of Cu{2 0 0} is nonlinear with a inflection at about 180 °C. The microstructures of Cu matrix before and after thermal expansion testing were investigated using transmission electronic microscope. The anisotropic thermal expansion behavior is related to the deformation twinning formed in the matrix during heating process. At the same time, the deformation twinning of Cu matrix makes the average coefficient of thermal expansion of the composite increase.

  15. Microstrain temperature evolution in β-eucryptite ceramics: Measurement and model

    International Nuclear Information System (INIS)

    Bruno, G.; Garlea, V.O.; Muth, J.; Efremov, A.M.; Watkins, T.R.; Shyam, A.

    2012-01-01

    Mechanisms of microcracking and stress release in β-eucryptite ceramics were investigated by applying a combination of neutron diffraction (ND), dilatometry and the Integrity Factor Model (IFM). It was observed that the macroscopic thermal expansion of solid samples closely follows the lattice thermal expansion as a function of temperature, and both are dominated by microcracks closing (during heating) and opening (during cooling). Analogous experiments on powders showed that the stresses that manifest peak shift are indeed relieved by comminution, and that the resulting lattice thermal expansion can be considered as unconstrained. By means of Rietveld refinement of the ND data, the evolution with temperature of peak width parameters linked to strain distributions along the basal, pyramidal and axial planes could also be extracted. The peak width parameters S HKL correlated well with the strains calculated by peak shift and with the model results. Furthermore, while the peak shifts showed that the powders are basically stress free, the S HKL showed a strong evolution of the peak width. Powders carry, therefore, a measurable strain distribution inside the particles, owing to the thermal expansion anisotropy of the crystallites. The IFM allowed this behavior to be rationalized, and the effect of microcracking on thermal expansion to be quantified. Experimental data allowed accurate numerical prediction of microcracking on cooling and of the evolution of microstresses. They also allowed the derivation of the material elastic modulus from bulk thermal expansion curves through the IFM concept. Ultrasound resonance measurements of the elastic modulus strongly support these theoretical predictions.

  16. Kinetic study on the chlorination of β-spodumene for lithium extraction with Cl2 gas

    International Nuclear Information System (INIS)

    Barbosa, L.I.; Valente, N.G.; González, J.A.

    2013-01-01

    Highlights: ► β-Spodumene was chlorinated to extract lithium with pure chlorine. ► The kinetics of the chlorination was studied in the range of 1000–1100 °C. ► Cl 2 flow rate, sample mass, and Cl 2 partial pressure were the operating variables. ► Experimental data were best fitted by the sequential nucleation and growth model. - Abstract: In this paper, the kinetics chlorination of β-spodumene for the extraction of lithium has been studied using gaseous chlorine as chlorinating agent. The effect of chlorine flow rate, temperature, mass of the sample, and partial pressure of Cl 2 was investigated. The study of the effect of chlorine flow rate indicated that the chlorination of β-spodumene may be carried out in the presence of active chlorinating species The chlorine partial pressure was found to have an appreciable effect on the system reactivity. The temperature was found to be the most important variable affecting the reaction rate. The β-spodumene chlorination process by Cl 2 was characterized by an apparent activation energy of about 359 kJ/mol in the range from 1000 to 1100 °C. Reaction was of non-catalytic gas–solid nature and experimental data fitted the sequential nucleation and growth model

  17. Optical properties of alpha spodumene: Orientation of its principal optical axes

    Energy Technology Data Exchange (ETDEWEB)

    Souza, S O; Lima, A F [Universidade Federal de Sergipe, Departamento de Fisica, PO Box 353, 49100-000 Sao Cristovao - SE (Brazil); Lalic, M V, E-mail: mlalic@fisica.ufs.b

    2009-05-01

    We studied the orientation of the three orthogonal principal optical axes of the alpha spodumene crystal. This orientation is determined relative to the crystallographic axes, and expressed as function of the incident radiation wavelength in ultraviolent region. The calculations were performed by density functional theory based, full potential augmented plane wave method.

  18. Mechanical and thermal expansion properties of β-eucryptite prepared by sol-gel methods and hot pressing

    International Nuclear Information System (INIS)

    Xia, L.; Wen, G.W.; Qin, C.L.; Wang, X.Y.; Song, L.

    2011-01-01

    Research highlights: → Dense LAS glass-ceramics were fabricated by sol-gel and hot pressing technique. → The LAS glass-ceramics have relative good mechanical properties. → The negative thermal expansion behavior of LAS glass-ceramics was investigated. -- Abstract: The microstructures, mechanical properties and thermal expansion behavior of monolithic lithium aluminosilicate glass-ceramics, prepared by sol-gel method and hot pressing, were investigated by using X-ray diffraction, scanning and transmission electron microscopies, three-point bend tests and dilatometry. β-eucryptite appeared as main phase in the monolithic lithium aluminosilicate glass-ceramics. The glass ceramics exhibited high relative densities and the average flexural strength and fracture toughness values were 154 MPa and 2.46 MPa m 1/2 , respectively. The lithium aluminosilicate glass-ceramics hot pressed 1300 and 1350 o C demonstrated negative coefficient of thermal expansion, which was affected by amount and type of crystalline phases.

  19. Investigation of Enhanced Leaching of Lithium from α-Spodumene Using Hydrofluoric and Sulfuric Acid

    Directory of Open Access Journals (Sweden)

    Hui Guo

    2017-10-01

    Full Text Available An effective method using hydrofluoric and sulfuric acid was proposed to enhance the leaching of lithium from α-spodumene, without calcination that is subjected to 1000 °C for phase transformation. The thermodynamic feasibility of the reactions was firstly verified. Dissolution conditions were tested to maximize the leaching efficiency of lithium and with efficient utilization of hydrofluoric acid (HF served as evaluation criteria. The results showed that 96% of lithium could be transferred into lixivium with an ore/HF/H2SO4 ratio of 1:3:2 (g/mL/mL, at 100 °C for 3 h. Due to the fact that HF molecules were the main reaction form, the dissolution behaviors were theoretically represented and investigated by dissolution in HF/H2SO4. When combined with chemical elements analyses and characterizations, the results of the dissolution behaviors revealed that α-spodumene and albite were preferentially dissolved over quartz. Insoluble fluoroaluminates, such as AlF3, cryolite (Na3AlF6 and cryolithionite (Na3Li3Al2F12, were generated and might be further partially dissolved by H2SO4. Fluorosilicates, such as K2SiF6, Na2SiF6, or KNaSiF6, were also generated as a part of the insoluble residues. This work provides fundamental insight into the role of HF/H2SO4 played in the dissolution of α-spodumene, and sheds light on a novel and promising process to efficiently extract lithium.

  20. Determining Age and Origin of Spodumene-Bearing Pegmatites in Southeastern Ireland

    Science.gov (United States)

    Brown, A. A.; Barros, R.; Menuge, J. F.

    2017-12-01

    Exploration prospecting around Caldonian Leinster Granite has revealed pegmatite intrusions containing spodumene, a lithium ore, on the eastern margin of the Tullow Lowlands Pluton. Drill cores of these pegmatites have been extracted and studied due to increasing economic interest. Ages between 430 and 400 Ma for spodumene pegmatites have been previously determined using the in situ Rb-Sr isochron method [1]. Here we use the Sm-Nd isochron method to see if the less-mobile nature of REEs during contact metamorphism and deformation impacts ages. Suitable samples containing garnet and feldspar from spodumene and barren pegmatites were studied using regular microscopy and SEM; minerals were then isolated manually. After mineral dissolution and elemental separation via ion exchange columns, a Neptune MS measured Sm and Nd isotope ratios. Blank corrections were applied. Both types of pegmatites were used to calculate an isochron using Isoplot 3.7 [2] which yielded an initial 143Nd/144Nd ratio of 0.51190±0.00009, and an age of 414±52 Ma. Ages and ɛNd, relating to the initial Nd ratio, were compared with previous whole rock data of Leinster Granite [3] and Rb-Sr multimineral data [1]. Comparable ages from both methods likely represent crystallization age. At the minimum possible age considering uncertainty, the origins of pegmatites and granitic rocks are indistinguishable, but at the maximum age, pegmatites show lower ɛNd values suggesting heterogeneous sources. All representative data points held negative ɛNd values signifying crustal assimilation. The Sm-Nd method was found suitable for age/ source investigation; however, Leinster pegmatite garnet is particularly depleted in Nd (Microsoft Excel. Berkeley Geochronology Center Special Publication, 4 [3] Mohr, Peter (1991): "Cryptic Sr and Nd isotopic variation across the Leinster Granite, Southeast Ireland" Geology Magazine, Vol 128, 3, 251-256

  1. Extraction of lithium from β-spodumene using chlorination roasting with calcium chloride

    Energy Technology Data Exchange (ETDEWEB)

    Barbosa, Lucía I., E-mail: lbarbosa@unsl.edu.ar [Instituto de Investigaciones en Tecnología Química (INTEQUI-CONICET), Facultad de Química Bioquímica y Farmacia, Universidad Nacional de San Luis, Chacabuco 17, CP 5700 San Luis (Argentina); González, Jorge A. [Instituto de Investigaciones en Tecnología Química (INTEQUI-CONICET), Facultad de Química Bioquímica y Farmacia, Universidad Nacional de San Luis, Chacabuco 17, CP 5700 San Luis (Argentina); Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Cuyo, Padre Jorge Contreras 1300, Parque General San Martín, CP M5502JMA Mendoza (Argentina); Ruiz, María del Carmen [Instituto de Investigaciones en Tecnología Química (INTEQUI-CONICET), Facultad de Química Bioquímica y Farmacia, Universidad Nacional de San Luis, Chacabuco 17, CP 5700 San Luis (Argentina)

    2015-04-10

    Highlights: • β-Spodumene was roasted with calcium chloride to extract lithium. • The optimal conditions of the chlorination process are 900 °C and 120 min. • The products of the reaction are lithium chloride, anorthite, and silica. - Abstract: Chlorination roasting was used to extract lithium as lithium chloride from β-spodumene. The roasting was carried out in a fixed bed reactor using calcium chloride as chlorinating agent. The mineral was mixed with CaCl{sub 2} on a molar ratio of 1:2. Reaction temperature and time were investigated. The reactants and roasted materials were characterized by X-ray fluorescence (XRF), X-ray diffraction (XRD) and atomic absorption spectrophotometry (AAS). The mineral starts to react with CaCl{sub 2} at around 700 °C. The optimal conditions of lithium extraction were found to be 900 °C and 120 min of chlorination roasting, under which it is attained a conversion degree of 90.2%. The characterization results indicate that the major phases present in the chlorinating roasting residue are CaAl{sub 2}Si{sub 2}O{sub 8}, SiO{sub 2}, and CaSiO{sub 3}.

  2. Study of the Extraction Kinetics of Lithium by Leaching β-Spodumene with Hydrofluoric Acid

    Directory of Open Access Journals (Sweden)

    Gustavo D. Rosales

    2016-09-01

    Full Text Available Parameters affecting the kinetics of the dissolution of β-spodumene with hydrofluoric acid have been investigated. The experimental tests were carried out in a closed vessel. The influence of several parameters, such as stirring speed, temperature, and reaction time were studied in order to deduce the kinetics of the dissolution reaction. The other parameters, particle size −45 μm; HF concentration 4% v/v, and the solid–liquid ratio 0.95% w/v were kept constant. The results indicate that the stirring speed does not have an important effect on the dissolution of the mineral above 330 rpm. The extent of the leaching of β-spodumene increases with temperature and reaction time augmentations. Scanning electron microscope (SEM analyses of some residues in which the conversion was lower than 30% indicated a selective attack on certain zones of the particle. The treatment of the experimental data was carried out using the Modelado software. The model that best represents the dissolution of the mineral is the following: ln(1 − X = −b1 [ln(1 + b2t − b2t/(1 + b2t]. This model is based on “nucleation and growth of nuclei” theory, and describes the style of attack physically observed by SEM on the residues.

  3. Extraction of lithium from β-spodumene using chlorination roasting with calcium chloride

    International Nuclear Information System (INIS)

    Barbosa, Lucía I.; González, Jorge A.; Ruiz, María del Carmen

    2015-01-01

    Highlights: • β-Spodumene was roasted with calcium chloride to extract lithium. • The optimal conditions of the chlorination process are 900 °C and 120 min. • The products of the reaction are lithium chloride, anorthite, and silica. - Abstract: Chlorination roasting was used to extract lithium as lithium chloride from β-spodumene. The roasting was carried out in a fixed bed reactor using calcium chloride as chlorinating agent. The mineral was mixed with CaCl 2 on a molar ratio of 1:2. Reaction temperature and time were investigated. The reactants and roasted materials were characterized by X-ray fluorescence (XRF), X-ray diffraction (XRD) and atomic absorption spectrophotometry (AAS). The mineral starts to react with CaCl 2 at around 700 °C. The optimal conditions of lithium extraction were found to be 900 °C and 120 min of chlorination roasting, under which it is attained a conversion degree of 90.2%. The characterization results indicate that the major phases present in the chlorinating roasting residue are CaAl 2 Si 2 O 8 , SiO 2 , and CaSiO 3

  4. Preparation of. beta. -spodumene glass-ceramics from blast furnace slag. Koro slag wo genryo to shita. beta. -spodumene kei kesshoka glass no seizo

    Energy Technology Data Exchange (ETDEWEB)

    Wang, M. (National Kaoshing Institute Technology, Kaoshiung (Rep. of China)); Hon, M. (National Cheng Kung University, Tainan (Rep. of China))

    1990-07-01

    Li {sub 2} O-CaO-Al {sub 2} O {sub 3} -SiO {sub 2} (LCAS) glass-ceramics were prepared from blast furnace slag by quenching in water after heating at 1,450 {degree} C for 3 hours. Blast furnace slag (40.0wt%) containing CaO, MgO, Al {sub 2} O {sub 3} and SiO {sub 2} as major components was used as a raw material, and batch compositions were modified by mixing blast furnace slag with Al {sub 2} O {sub 3}, SiO {sub 2} and Li {sub 2} CO {sub 3}, and a nucleating agent TiO {sub 2}. The A specimen with TiO {sub 2} of 7.4wt% and B specimen with 4.6wt% were prepared, and the crystallization process of the glass was examined with X-ray diffraction, electron diffraction and so forth. As a result, a major crystalline phase was {beta} -spodumene (Li {sub 2} O-Al {sub 2} O {sub 3} -4SiO {sub 2}), and the average thermal expansion coefficients of A and B were 40.1 and 47.2 {times} 10 {sup {minus} 7} / {degree} C in the temperature range from 25 to 700 {degree} C, respectively. A small amount of titanite was also observed in A as a sub-phase. 14 refs., 5 figs., 3 tabs.

  5. Anisotropic surface physicochemical properties of spodumene and albite crystals: Implications for flotation separation

    Science.gov (United States)

    Xu, Longhua; Peng, Tiefeng; Tian, Jia; Lu, Zhongyuan; Hu, Yuehua; Sun, Wei

    2017-12-01

    Aluminosilicate minerals (e.g., spodumene, albite) have complex crystal structures and similar surface chemistries, but they have poor selectivity compared to traditional fatty acid collectors, making flotation separation difficult. Previous research has mainly considered the mineral crystal structure as a whole. In contrast, the surface characteristics at the atomic level and the effects of different crystal interfaces on the flotation behavior have rarely been investigated. This study focuses on investigating the surface anisotropy quantitatively, including the chemical bond characteristics, surface energies, and broken bond densities, using density functional theory and classical theoretical calculations. In addition, the anisotropy of the surface wettability and adsorption characteristics were examined using contact angle, zeta potential, and Fourier-transform infrared measurements. Finally, these surface anisotropies with different flotation behaviors were investigated and interpreted using molecular dynamics simulations, scanning electron microscopy, and X-ray photoelectron spectroscopy. This systematic research offers new ideas concerning the selective grinding and stage flotation of aluminosilicate minerals based on the crystal characteristics.

  6. Optical absorption and electron spin resonance in natural, irradiated and heated spodumene

    International Nuclear Information System (INIS)

    Ito, A.S.; Isotani, S.

    1983-09-01

    Heat treatment and X and γ-Rays irradiation of lylac and colorless natural spodumene, LiAlSi 2 O 6 , have been studied. Irradiation produces a color change, from lylac or colorless to green. Irradiated samples heated at 200 0 C turn lylac and bleach at 400 0 C. Optical absorption spectra were decomposed into gaussian line shape bands and it is observed that green and lylac centers are simultaneously created by irradiation. These centers are independent from each other. Optical absorption, EPR and X-Ray fluorescence results show the spectra of impurities, responsible by the presence of the created centers and indicated Mn participation in the process of centers creation and destruction. Decay Kinetics of green and lylac centers have been studied and it is observed that simple Kinetic models do not apply to these cases. An empirical fit allowed the calculation of activation energies of the lylac and green centers decays. Discussions about the present results led us to propose a new model where the green and lylac centers are due to Mn 3+ ions in two different Al 3+ sites, whose absorption are intensified by the interaction with an electron trapped in a neighbour oxygen. (Author) [pt

  7. High temperature behavior of eucryptite by means of in situ X ray diffraction studies; Comportamiento de la eucriptita a alta temperatura mediante estudio in situ por difraccion de Rayos X

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Moreno, O.; Khainakov, S.; Torrecillas, R.

    2012-11-01

    Eucryptite is a lithium aluminosilicate with striking thermal expansion properties: it has negative expansion, i. e. it contracts upon heating in one of its crystallographic dimensions. Due to this characteristic, eucryptite is used in the fabrication of very low coefficient of thermal expansion materials. Two different eucryptite solid solution compositions were synthesized in this study with Li{sub 2}O:Al{sub 2}O{sub 3}:SiO{sub 2} contents of 1:1:3 and 1:1:2. The synthesis was prepared using kaolinite, lithium carbonate and TEOS and o {gamma} Al{sub 2}O{sub 3}, respectively. High resolution X Ray diffraction characterization was performed at high temperature for both compositions between 25 and 1200 degree centigrade. The temperature effect on structure and composition was studied by determining cell parameters and crystal structures. The relation between the observed changes and the CTE variations with the sintering temperature of materials based in these compositions was finally determined. (Author) 19 refs.

  8. Rocha com espodumênio como fundente para massas cerâmicas tradicionais Spodumene rock as a flux for traditional ceramic bodies

    Directory of Open Access Journals (Sweden)

    S. R. Bragança

    2010-07-01

    Full Text Available Investigou-se a atuação de uma rocha com espodumênio como fundente em massas cerâmicas, analisando-se sua reatividade com outras matérias-primas, como quartzo e caulim. Primeiramente, caracterizou-se petrograficamente o pegmatito de onde se extrai esse fundente. Posteriormente avaliou-se o comportamento de moabilidade, fundência e deformação piroplástica da rocha com espodumênio. Analisou-se então sua influência nas propriedades tecnológicas finais das peças, principalmente em relação à temperatura de queima, às fases e à microestrutura. Comparou-se a gresificação com outros fundentes comerciais como a albita e o feldspato. O espodumênio mostrou maior capacidade de reduzir a temperatura de gresificação das peças que os fundentes tradicionais, promovendo a densificação por fluxo viscoso.A spodumene rock was used as a flux in ceramic bodies, analyzing its reactivity to other raw materials such as quartz and kaolin. The petrology properties of the pegmatite (parent rock from which the flux is extracted was characterized. The grindability, fluxing strength and pyroplastic deformation of the spodumene rock were investigated. The influence on technological properties of the final pieces, mainly in relation to the firing temperature, phases formation and microstructure were also further analyzed. The firing behavior to other commercial flux such as albite and feldspar were then compared. The spodumene rock was considered an effective flux, capable of reducing the firing temperatures of the tested bodies by viscous flow.

  9. Homogenization Experiments of Crystal-Rich Inclusions in Spodumene from Jiajika Lithium Deposit, China, under Elevated External Pressures in a Hydrothermal Diamond-Anvil Cell

    Directory of Open Access Journals (Sweden)

    Jiankang Li

    2017-01-01

    Full Text Available Extensive studies of the crystal-rich inclusions (CIs hosted in minerals in pegmatite have resulted in substantially different models for the formation mechanism of the pegmatite. In order to evaluate these previously proposed formation mechanisms, the total homogenization processes of CIs hosted in spodumene from the Jiajika pegmatite deposit in Sichuan, China, were observed in situ under external H2O pressures in a new type of hydrothermal diamond-anvil cell (HDAC. The CIs in a spodumene chip were loaded in the sample chamber of HDAC with water, such that the CIs were under preset external H2O pressures during heating to avoid possible decrepitation. Our in situ observations showed that the crystals within the CIs were dissolved in carbonic-rich aqueous fluid during heating and that cristobalite was usually the first mineral being dissolved, followed by zabuyelite and silicate minerals until their total dissolution at temperatures between 500 and 720°C. These observations indicated that the minerals within the CIs were daughter minerals crystallized from an entrapped carbonate- and silica-rich aqueous solution and therefore provided useful information for evaluating the formation models of granitic pegmatites.

  10. Cationic flotation of some lithium ores

    International Nuclear Information System (INIS)

    Valadao, G.E.S.; Peres, A.E.C.; Silva, H.C. da

    1984-01-01

    The cationic flotation of some lithium ores (spodumene, amblygonite, petalite, lepidolite) is studied by the measure of zeta potential and micro-flotation tests in Hallimond tube. The effect of some modifier agents (corn starch, meta sodium silicate) on the lithium flotation is studied. (M.A.C.) [pt

  11. Preparation and properties of Li2O-BaO-Al2O3 -SiO2 glass-ceramic materials

    Directory of Open Access Journals (Sweden)

    Gamal A. Khater

    2014-12-01

    Full Text Available The crystallization of some glasses, based on celsian-spodumene glass-ceramics, was investigated by different techniques including differential thermal analysis, optical microscope, X-ray diffraction, indentation, microhardness, bending strengths, water absorption and density measurement. The batches were melted and then cast into glasses, which were subjected to heat treatment to induce controlled crystallization. The resulting crystalline materials were mainly composed of β-eucryptite solid solution, β-spodumene solid solution, hexacelsian and monoclinic celsian, exhibiting fine grains and uniform texture. It has been found that an increasing content of celsian phase in the glasses results in increased bulk crystallization. The obtained glass-ceramic materials are characterized by high values of hardness ranging between 953 and 1013 kg/mm2, zero water absorption and bending strengths values ranging between 88 and 126 MPa, which makes them suitable for many applications under aggressive mechanical conditions.

  12. Near zero coefficient of thermal expansion of beta-eucryptite without microcracking

    Science.gov (United States)

    Reimanis, Ivar; Ramalingam, Subramanian

    2015-06-16

    The present invention is drawn to a lithia alumina silica material that exhibits a low CTE over a broad temperature range and a method of making the same. The low CTE of the material allows for a decrease in microcracking within the material.

  13. Dosimetric and thermoluminescent characteristics of sintered samples based on Li{sub 2}OAl{sub 2}O{sub 3}nSiO{sub 2} systems

    Energy Technology Data Exchange (ETDEWEB)

    Cogollo P, R.; Salcedo Q, J. [Universidad de Cordoba, Materials and Applied Physics Group, Carrera 6 No. 76-103, Monteria, Cordoba (Colombia); Gutierrez F, O., E-mail: rafaelcogollo@correo.unicordoba.edu.co [Metropolitan Technological Institute, Alquimia Group, Calle 54 No. 30-01, Medellin (Colombia)

    2013-10-01

    This work describes the thermoluminescent (Tl) characteristics of lithium aluminosilicates, Li{sub 2}OAl{sub 2}O{sub 3}nSiO{sub 2}, for its possible use as Tl dosimeter for low doses. The sinterized tablets of Li{sub 2}OAl{sub 2}O{sub 3}nSiO{sub 2} were characterized by means of X-ray diffraction (XRD), and irradiated at different doses using a Theratron 780 C-{sup 60}Co unit in air at room temperature. The Rasheedy's technique was used for the kinetic trap parameters determination. The XRD results show a mixture of two phases of 64% {beta}-spodumene and 36% {beta}-eucryptite in the sinterized tablets. Tl analysis indicates that in these systems, recombination processes prevail, and that these systems can be used successfully as Tl dosimeters for therapeutic dose ranges. (Author)

  14. OH-point defects in quartz in B- and Li-bearing systems and their application to pegmatites

    Science.gov (United States)

    Baron, M. A.; Stalder, R.; Konzett, J.; Hauzenberger, C. A.

    2015-01-01

    OH incorporation in quartz in Al-, B- and Li-bearing systems (granitic systems containing tourmaline or spodumene) was studied experimentally in order to investigate the effect of pressure, temperature and chemical impurities on the generation of OH-defects. High-pressure experiments were carried out at pressures between 5 and 25 kbar and temperatures between 800 and 900 °C, and OH-contents in quartz were calculated from IR absorption spectra measured on oriented quartz crystals. IR absorption features were assigned to impurity substitutions, such as AlOH (3,420, 3,379 and 3,315 cm-1) and BOH (3,595 cm-1), LiOH (3,483 cm-1), and hydrogarnet substitution (4H)Si defects (3,583 cm-1). Results indicate a negative correlation of incorporated Al-specific OH-defect content versus pressure (630 ± 130 wt ppm H2O at 5 kbar to 102 ± 6 wt ppm H2O at 25 kbar), but no clear correlation of B-specific OH-defects with pressure. In runs initially containing spodumene, virtually OH-free quartzes were observed at pressures ≥10 kbar, where impurity cations compensate each other forming an anhydrous eucryptite-defect component. In contrast, at 5 kbar, both Li- ad Al-specific OH-defects are observed (corresponding to 470 ± 75 wt ppm H2O). Results from this study may therefore be used to monitor formation conditions of quartz in terms of pressure and trace metal saturation of the crystallizing petrological system. IR spectra obtained from natural quartz grains from a tourmaline-bearing pegmatite exhibit B- and Al-related OH-bands. The B-related OH-band is also exhibited in quartz from a tourmaline + spodumene-bearing pegmatite. Li- and Al-related OH-bands, however, are subordinate or not observed at all in the spodumene-bearing system, which suggests that OH-vibrations do not reflect absolute Li-contents in quartz due to efficient coupled substitution involving Al. Data from experimental runs and natural specimens indicate that the B-related OH-band can be used as a rough proxy for

  15. Litiniferous pegmatites from Itinga-Aracuai region, Minas Gerais, Brazil

    International Nuclear Information System (INIS)

    Silva Sa, J.H. da.

    1977-01-01

    This work explains the study of more a hundred pegmatites from Itinga and Aracuai, in middle Jequitinhonha. This area have cassiterite, tantalite-columbite, semiprecious stones ad lithium minerals. The lithium ores are the most economic importance. The predominate rocks are quartz-mica schist, rich in cordierite. Geochronological dating, by the Rb-Sr method, show ages about 650 m.a. to schist and 520 m.a. to the granites. Was dated muscovites from two pegmatites by K-Ar method showing ages about 4677+- 18 m.a and 490 +- 12 m.a. The pegmatites was classified in simple and complex, based in mineralogical and structural criterion. In the complex pegmatites was determinated notable accessory minerological association, in which the principal are lithium ores-petalite, spodumene, lepidolite, ambligonite, the cesium ore-polucite-and cassiterite, tantalite-columbite, and great variety of turmaline. Genetically the pegmatites are related with the granites of this region, with present high tenor of the lithium, cesium and beryllium, comparate with the normal granites. (C.D.G.) [pt

  16. Applications of lithium in nuclear energy

    Energy Technology Data Exchange (ETDEWEB)

    Oliviera, Glaucia A.C. de; Bustillos, José O.V.; Ferreira, João C.; Bergamaschi, Vanderlei S.; Moraes, Rafaeli M. de; Gimenez, Maíse P.; Miyamoto, Flavia K.; Seneda, José A., E-mail: glaucia.oliveira@ipen.br, E-mail: ovega@ipen.br, E-mail: jcferrei@ipen.br, E-mail: vsberga@ipen.br, E-mail: rafaeli.medeiros.moraes@gmail.com, E-mail: maisepastore@hotmail.com, E-mail: fla.kimiyamoto@gmail.com, E-mail: jaseneda@ipen.br [Instituto de Pesquisas Energéticas e Nucleares (IPEN-CNEN/SP), Paulo, SP (Brazil)

    2017-07-01

    Lithium is a material of great interest in the world, it is found in different minerals on Earth's crust (spodumene, lepidolite, amblygonite and petalite) also in salt pans. This element belongs to alkaline group and has two natural isotopes: Li-6 and Li-7. In the nuclear field, lithium isotopes are used for different purposes. The Li-6 is applied in the production of energy, because its section of shock is larger than the other isotope. The Li-7 regulates the pH in refrigerant material in the primary circuits of the Pressurized Water Nuclear Reactor (PWR). In nuclear reactor, lithium is used as a heat transfer due its boiling temperature (1342°C), making it an excellent thermal conductor. However, to reach all these applications, lithium must have high purity (> 99%). The main processes to reach a high purity level of lithium employee a combination of solvent extraction and ion exchange process, to obtain its salts or ending with chemical electrolysis of its chlorides to obtain its pure metal. This work presents a review of new applications of Lithium in Nuclear Energy and its purification and enrichment processes. (author)

  17. Applications of lithium in nuclear energy

    International Nuclear Information System (INIS)

    Oliviera, Glaucia A.C. de; Bustillos, José O.V.; Ferreira, João C.; Bergamaschi, Vanderlei S.; Moraes, Rafaeli M. de; Gimenez, Maíse P.; Miyamoto, Flavia K.; Seneda, José A.

    2017-01-01

    Lithium is a material of great interest in the world, it is found in different minerals on Earth's crust (spodumene, lepidolite, amblygonite and petalite) also in salt pans. This element belongs to alkaline group and has two natural isotopes: Li-6 and Li-7. In the nuclear field, lithium isotopes are used for different purposes. The Li-6 is applied in the production of energy, because its section of shock is larger than the other isotope. The Li-7 regulates the pH in refrigerant material in the primary circuits of the Pressurized Water Nuclear Reactor (PWR). In nuclear reactor, lithium is used as a heat transfer due its boiling temperature (1342°C), making it an excellent thermal conductor. However, to reach all these applications, lithium must have high purity (> 99%). The main processes to reach a high purity level of lithium employee a combination of solvent extraction and ion exchange process, to obtain its salts or ending with chemical electrolysis of its chlorides to obtain its pure metal. This work presents a review of new applications of Lithium in Nuclear Energy and its purification and enrichment processes. (author)

  18. Buli. Mater. Sci., Vol. 20, No. 2, April 1997, pp. 247-257. (C

    Indian Academy of Sciences (India)

    Synthesis of spodumene and spodumene-zirconia composite ... were prepared using aqueous sol-gel method employing lithium formate, aluminium formate, ... synthesis and the processing of spodumene using different precursor compounds.

  19. Investigation of Thermal Expansion of a Glass Ceramic Material with an Extra-Low Thermal Linear Expansion Coefficient

    Science.gov (United States)

    Kompan, T. A.; Korenev, A. S.; Lukin, A. Ya.

    2008-10-01

    The artificial material sitall CO-115M was developed purposely as a material with an extra-low thermal expansion. The controlled crystallization of an aluminosilicate glass melt leads to the formation of a mixture of β-spodumen, β-eucryptite, and β-silica anisotropic microcrystals in a matrix of residual glass. Due to the small size of the microcrystals, the material is homogeneous and transparent. Specific lattice anharmonism of these microcrystal materials results in close to zero average thermal linear expansion coefficient (TLEC) of the sitall material. The thermal expansion coefficient of this material was measured using an interferometric method in line with the classical approach of Fizeau. To obtain the highest accuracy, the registration of light intensity of the total interference field was used. Then, the parameters of the interference pattern were calculated. Due to the large amount of information in the interference pattern, the error of the calculated fringe position was less than the size of a pixel of the optical registration system. The thermal expansion coefficient of the sitall CO-115M and its temperature dependence were measured. The TLEC value of about 3 × 10-8 K-1 to 5 × 10-8 K-1 in the temperature interval from -20 °C to +60 °C was obtained. A special investigation was carried out to show the homogeneity of the material.

  20. The influence of Al2O3, MgO and ZnO on the crystallization characteristics and properties of lithium calcium silicate glasses and glass-ceramics

    International Nuclear Information System (INIS)

    Salman, S.M.; Darwish, H.; Mahdy, E.A.

    2008-01-01

    The crystallization characteristics of glasses based on the Li 2 O-CaO-SiO 2 eutectic (954 ± 4 deg. C) system containing Al 2 O 3 , MgO and ZnO has been investigated by differential thermal analysis (DTA), X-ray diffraction analysis (XRD), and scanning electron microscopy (SEM). The partial replacement of Li 2 O by Al 2 O 3 and CaO by MgO or ZnO in the studied glass-ceramics led to the development of different crystalline phase assemblages, including lithium meta- and di-silicates, lithium calcium silicates, α-quartz, diopside, clinoenstatite, wollastonite, β-eucryptite ss, β-spodumene, α-tridymite, lithium zinc orthosilicate, hardystonite and willemite using various heat-treatment processes. The dilatometric thermal expansion of the glasses and their corresponding glass-ceramics were determined. A wide range of thermal expansion coefficient values were obtained for the investigated glasses and their corresponding crystalline products. The thermal expansion coefficients of the investigated glasses were decreased by Al 2 O 3 , MgO or ZnO additions. The α-values of the investigated glasses were ranged from (+18) to (+108) x 10 -7 K -1 (25-300 deg. C), while those of the glass-ceramics were (+3) to (+135) x 10 -7 K -1 (25-700 deg. C). The chemical durability of the glass-ceramics, towards the attack of 0.1N HCl solution, was markedly improved by Al 2 O 3 with MgO replacements. The composition containing 11.5 mol% Al 2 O 3 and 6.00 mol% MgO exhibited low thermal expansion values and good chemical durability

  1. Mineral-deposit model for lithium-cesium-tantalum pegmatites

    Science.gov (United States)

    Bradley, Dwight C.; McCauley, Andrew D.; Stillings, Lisa L.

    2017-06-20

    Lithium-cesium-tantalum (LCT) pegmatites comprise a compositionally defined subset of granitic pegmatites. The major minerals are quartz, potassium feldspar, albite, and muscovite; typical accessory minerals include biotite, garnet, tourmaline, and apatite. The principal lithium ore minerals are spodumene, petalite, and lepidolite; cesium mostly comes from pollucite; and tantalum mostly comes from columbite-tantalite. Tin ore as cassiterite and beryllium ore as beryl also occur in LCT pegmatites, as do a number of gemstones and high-value museum specimens of rare minerals. Individual crystals in LCT pegmatites can be enormous: the largest spodumene was 14 meters long, the largest beryl was 18 meters long, and the largest potassium feldspar was 49 meters long.Lithium-cesium-tantalum pegmatites account for about one-fourth of the world’s lithium production, most of the tantalum production, and all of the cesium production. Giant deposits include Tanco in Canada, Greenbushes in Australia, and Bikita in Zimbabwe. The largest lithium pegmatite in the United States, at King’s Mountain, North Carolina, is no longer being mined although large reserves of lithium remain. Depending on size and attitude of the pegmatite, a variety of mining techniques are used, including artisanal surface mining, open-pit surface mining, small underground workings, and large underground operations using room-and-pillar design. In favorable circumstances, what would otherwise be gangue minerals (quartz, potassium feldspar, albite, and muscovite) can be mined along with lithium and (or) tantalum as coproducts.Most LCT pegmatites are hosted in metamorphosed supracrustal rocks in the upper greenschist to lower amphibolite facies. Lithium-cesium-tantalum pegmatite intrusions generally are emplaced late during orogeny, with emplacement being controlled by pre-existing structures. Typically, they crop out near evolved, peraluminous granites and leucogranites from which they are inferred to be

  2. Stress relief of ceramic components in high voltage assemblies. Final report

    International Nuclear Information System (INIS)

    Heinen, R.J.

    1979-02-01

    Two types of ceramic packages were evaluated to determine the effectiveness of encapsulating the ceramic components in beta eucryptite filled epoxy. The requirements (no high voltage breakdown, no ceramic cracking, and no encapsulant cracking) were met by the spark gap assembly, but the sprytron assembly had cracking in the encapsulant after thermal cycling. The encapsulation of the ceramic component in beta eucryptite filled epoxy with a stress decoupling material selectively applied in the stress concentrated areas were used to prevent cracking in the sprytron encapsulant. This method is proposed as the standard encapsulation process for high voltage ceramic components

  3. Pressure Induced Phase Transformations in Ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Reimanis, Ivar [Colorado School of Mines, Golden, CO (United States); Cioabanu, Cristian [Colorado School of Mines, Golden, CO (United States)

    2017-10-15

    The study of materials with unusual properties offers new insight into structure-property relations as well as promise for the design of novel composites. In this spirit, the PIs seek to (1) understand fundamental mechanical phenomena in ceramics that exhibit pressure-induced phase transitions, negative coefficient of thermal expansion (CTE), and negative compressibility, and (2) explore the effect of these phenomena on the mechanical behavior of composites designed with such ceramics. The broad and long-term goal is to learn how to utilize these unusual behaviors to obtain desired mechanical responses. While the results are expected to be widely applicable to many ceramics, most of the present focus is on silicates, as they exhibit remarkable diversity in structure and properties. Eucryptite, a lithium aluminum silicate (LiAlSiO4), is specifically targeted because it exhibits a pressure-induced phase transition at a sufficiently low pressure to be accessible during conventional materials processing. Thus, composites with eucryptite may be designed to exhibit a novel type of transformation toughening. The PIs have performed a combination of activities that encompass synthesis and processing to control structures, atomistic modeling to predict and understand structures, and characterization to study mechanical behavior. Several materials behavior discoveries were made. It was discovered that small amounts of Zn (as small as 0.1 percent by mol) reverse the sign of the coefficient of thermal expansion of beta-eucryptite from negative to slightly positive. The presence of Zn also significantly mitigates microcracking that occurs during thermal cycling of eucryptite. It is hypothesized that Zn disrupts the Li ordering in beta-eucryptite, thereby altering the thermal expansion behavior. A nanoindentation technique developed to characterize incipient plasticity was applied to examine the initial stages of the pressure induced phase transformation from beta to

  4. Development of low-expansion ceramics with strength retention to elevated temperatures. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Hirschfeld, D.A.; Brown, J.J. Jr. [Virginia Polytechnic Inst. and State Univ., Blacksburg, VA (United States)

    1994-09-01

    The development of advanced engines has resulted in the need for new ceramic compositions which exhibit thermo-mechanical properties suitable for the engine environment, e.g., low thermal expansion, stability to 1,200 C, and thermal shock resistance. To meet these goals, a two phase research program was instituted. In the first phase, new oxide ceramics were identified in the AlPO{sub 4}-{beta}-eucryptite, {beta}-cristobalite, mullite and zircon systems. This research focused on screening and property characterization of ceramics in the four systems. The most promising compositions in the AlPO{sub 4}-{beta}-eucryptite and zircon systems were then further evaluated and developed in the second phase with the goal of being ready for prototype testing in actual engines. Of the compositions, calcium magnesium zirconium phosphate (zircon system) exhibits the most desirable properties and is presently being developed for commercialization.

  5. Development of glass ceramics for the incorporation of fission products

    International Nuclear Information System (INIS)

    De, A.K.; Luckscheiter, B.; Lutze, W.; Malow, G.; Schiewer, E.

    1976-01-01

    Spontaneous devitrification of fission-product-containing borosilicate glasses can be avoided by controlled crystallization after melting. Glass ceramics have been developed from a vitrified simulated waste and further improvement of product properties was achieved. In particular perovskite, h-celsian, diopside and eucryptite glass ceramics were prepared. These contained leach resistant host phases which exhibited considerable enrichment of long-lived fission products. All products showed increased impact resistance, but the thermal expansion was only slightly improved

  6. High temperature flow behaviour of SiC reinforced lithium

    Indian Academy of Sciences (India)

    The compressive flow behaviour of lithium aluminosilicate (LAS) glass, with and without SiC particulate reinforcements, was studied. The LAS glass crystallized to spodumene during high-temperature testing. The flow behaviour of LAS glass changed from Newtonian to non-Newtonian due to the presence of crystalline ...

  7. X-ray fluorescence analysis of Fe, Mn, Cr and V in natural silicate crystals

    International Nuclear Information System (INIS)

    Dias, O.L.; Albuquerque, A.R.P.L.; Isotani, S.

    1983-04-01

    Concentrations of Fe, Mn, Cr and V were determined in samples of beryl, topaz, tourmaline and spodumene by measuring the first order K sub(α) fluorescence lines. The intensity of these lines were calibrated by using beryl as the standard matrix. The matrices were prepared in the form of pressed pellets with 4:1 mixture of beryl and boric acid, where transition metal oxides were added. (Author) [pt

  8. X-ray fluorescence analysis of Fe, Mn, Cr and V in natural silicate crystals

    International Nuclear Information System (INIS)

    Dias, O.L.; Albuquerque, A.R.P.L.; Isotani, S.

    1983-01-01

    Concentrations of Fe, Mn, Cr and V were determined in samples of beryl, topaze, tourmaline and spodumene by measuring the first order Kα fluorescence lines. The intensity of these lines were calibrated by using beryl as the standard matrix. The matrices were prepared in the form of pressed pellets with 4:1 mixture of beryl and boric acid, where transition metal oxides were added. (Author) [pt

  9. Ionic diffusion in quartz studied by transport measurements, SIMS and atomistic simulations

    International Nuclear Information System (INIS)

    Sartbaeva, Asel; Wells, Stephen A; Redfern, Simon A T; Hinton, Richard W; Reed, Stephen J B

    2005-01-01

    Ionic diffusion in the quartz-β-eucryptite system is studied by DC transport measurements, SIMS and atomistic simulations. Transport data show a large transient increase in ionic current at the α-β phase transition of quartz (the Hedvall effect). The SIMS data indicate two diffusion processes, one involving rapid Li + motion and the other involving penetration of Al and Li atoms into quartz at the phase transition. Atomistic simulations explain why the fine microstructure of twin domain walls in quartz near the transition does not hinder Li + diffusion

  10. Influence of feldspar containing lithium in the sintering of triaxial ceramics

    International Nuclear Information System (INIS)

    Oliveira, Camila Felippe de; Strecker, Kurt

    2011-01-01

    In this work, the properties of a ceramic material based on a triaxial mass composed of clay, quartz and 15 to 30% feldspar, albite or spodumene, has been investigated. Specimen were prepared by uniaxial pressing under 28.5MPa and sintering at temperatures of 1000, 1100 and 1200 deg C, for 1h. The samples were characterized by their linear shrinkage, apparent porosity, apparent density and flexural strength, as well as analysis of the microstructure. The best results were obtained for samples prepared with 30% spodumene and sintered at 1200 deg C, with a shrinkage of 6.4%, density of 2.01g/cm 3 , porosity of 14.3% and flexural strength of 13.4MPa, while samples prepared with albite exhibited shrinkage of 5.8%, density of 1.9g/cm 3 , porosity of 18.9% and strength of 9.8MPa. Therefore, by the substitution of albite by spodumene in the ceramic triaxial mass, lower sintering temperatures may be employed, thus reducing production costs by the lesser energy consumption. (author)(

  11. Crystallization behavior of (1 - x)Li2O.xNa2O.Al2O3.4SiO2 glasses

    International Nuclear Information System (INIS)

    Wang, Moo-Chin; Cheng, Chih-Wei; Chang, Kuo-Ming; Hsi, Chi-Shiung

    2010-01-01

    The crystallization behavior of the (1 - x)Li 2 O.xNa 2 O.Al 2 O 3 .4SiO 2 glasses has been investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), electron diffraction (ED) and energy dispersive spectroscopy (EDS). The crystalline phase was composed of β-spodumene. The isothermal crystallization kinetics of β-spodumene from the (1 - x)Li 2 O.xNa 2 O.Al 2 O 3 .4SiO 2 glasses has also been studied by a quantitative X-ray diffraction method. The activation energy of β-spodumene formation decreases from 359.2 to 317.8 kJ/mol when the Na 2 O content increases from 0 to 0.4 mol and it increases from 317.8 to 376.9 kJ/mol when the Na 2 O content increases from 0.4 to 0.6 mol. The surface nucleation and plate-like growth were dominant in the crystallization of the (1 - x)Li 2 O.xNa 2 O.Al 2 O 3 .4SiO 2 glasses.

  12. Crystallization behavior of (1 - x)Li{sub 2}O.xNa{sub 2}O.Al{sub 2}O{sub 3}.4SiO{sub 2} glasses

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Moo-Chin [Department of Fragrance and Cosmetic Science, Kaohsiung Medical University, 100 Shih-Chuan 1st Road, Kaohsiung 807, Taiwan (China); Cheng, Chih-Wei; Chang, Kuo-Ming [Department of Mechanical Engineering, National Kaohsiung University of Applied Sciences, 415 Chien-Kung Road, Kaohsiung 80782, Taiwan (China); Hsi, Chi-Shiung, E-mail: chsi@nuu.edu.t [Department of Materials Science and Engineering, National United University, 1 Lien-Da, Kung-Ching Li, Miao-Li 36003, Taiwan (China)

    2010-07-02

    The crystallization behavior of the (1 - x)Li{sub 2}O.xNa{sub 2}O.Al{sub 2}O{sub 3}.4SiO{sub 2} glasses has been investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), electron diffraction (ED) and energy dispersive spectroscopy (EDS). The crystalline phase was composed of {beta}-spodumene. The isothermal crystallization kinetics of {beta}-spodumene from the (1 - x)Li{sub 2}O.xNa{sub 2}O.Al{sub 2}O{sub 3}.4SiO{sub 2} glasses has also been studied by a quantitative X-ray diffraction method. The activation energy of {beta}-spodumene formation decreases from 359.2 to 317.8 kJ/mol when the Na{sub 2}O content increases from 0 to 0.4 mol and it increases from 317.8 to 376.9 kJ/mol when the Na{sub 2}O content increases from 0.4 to 0.6 mol. The surface nucleation and plate-like growth were dominant in the crystallization of the (1 - x)Li{sub 2}O.xNa{sub 2}O.Al{sub 2}O{sub 3}.4SiO{sub 2} glasses.

  13. A novel deformation mechanism for superplastic deformation

    Energy Technology Data Exchange (ETDEWEB)

    Muto, H.; Sakai, M. (Toyohashi Univ. of Technology (Japan). Dept. of Materials Science)

    1999-01-01

    Uniaxial compressive creep tests with strain value up to -0.1 for a [beta]-spodumene glass ceramic are conducted at 1060 C. From the observation of microstructural changes between before and after the creep deformations, it is shown that the grain-boundary sliding takes place via cooperative movement of groups of grains rather than individual grains under the large-scale-deformation. The deformation process and the surface technique used in this work are not only applicable to explain the deformation and flow of two-phase ceramics but also the superplastic deformation. (orig.) 12 refs.

  14. Influence of the mould on the size of A A 8090 alloy in the material melting bulk state

    International Nuclear Information System (INIS)

    Bolfarini, Claudemiro

    1996-01-01

    Wedge like samples were casted into investment moulds of alumina and spodumen. The later were additionally coated with lithium, barium, magnesium and calcium fluorides and chlorides based salts and other special materials. It was used the 2,6% Li-containing alloy AA8090. The grain size was measured as a function of the wedge thickness nd mould material. The results showed a strong dependence of the grain size to the mould materials for the same cast conditions: pouring temperature, mould temperature and chemical composition of the alloy. The AA8090 alloy had no addition of titanium-boron based grain refiner. (author)

  15. Development of a monoenergetic 1-10 keV neutral lithium beam for the diagnostic of edge plasmas in magnetic confinement devices

    International Nuclear Information System (INIS)

    Ueda, Mario.

    1994-09-01

    Diagnostic of plasmas confined by magnetic fields for fusion research based on neutral lithium beam (NLB) is presently considered to be one of the most appropriate methods to carry out the important measurements of edge density and its fluctuation profiles without plasma perturbation. In this CRP project we proposed the development of an NLB source with 1-10 KeV based on a traditional β-eucryptite surface emission source coupled to a Pierce gun geometry accelerator and subsequent neutralization of the Li + beam by a Li-oven neutralizer. Possible application of such an NLB probe in a medium term (2-3 years) in our country would be in a small RFP in operation and in a low-aspect-ratio tokamak in construction both at LAP/INPE and in other hot plasma devices operating at brazilian universities of Sao Paulo (USP) and Campinas (UNICAMP) with whom we maintain strong collaboration efforts in plasma research. (author). 8 refs

  16. Thermal properties and crystallization of lithium–mica glass and glass-ceramics

    International Nuclear Information System (INIS)

    Nia, A. Faeghi

    2013-01-01

    Highlights: • Two groups of Li–mica glass-ceramics, have been compared. • By controlling the glass composition, crystalline lepidolite was obtained. • The T p of Li–mica was through the previous virgilite and eucryptite phase. - Abstract: The purpose of this study was the synthesis of two groups of Li–mica glass-ceramics denoted by lepidolite (Al 2.5 F 2 KLi 1.5 O 10 Si 3 ) and Li-phlogopite (LiMg 3 AlSi 3 O 10 F 2 ). The studied system was SiO 2 –Al 2 O 3 –MgO–K 2 O–Li 2 O. A total of 3 compositions were prepared. Bulk casted glasses and sintered glass-ceramics of Li-phlogopite and lepidolite systems, were prepared. Eucryptite and virgilite were two prior phases of lepidolite and Li-phlogopite crystallization. It was shown that the obtained glass-ceramics have lower TEC than corresponding glasses. Sinterability of lepidolite glass-ceramic was shown that improved by increasing the Al 2 O 3 content in glass composition. TEC and microhardness values were α = 6.08 × 10 −6 /°C, 755 ± 11.1, α = 7.86 × 10 −6 /°C, 739 ± 7.4 and α = 5.05 × 10 −6 /°C, 658 ± 6.2 HV for Li-lep, Klep1 and Klep2 glasses, respectively

  17. Crystallisation mechanism of a multicomponent lithium alumino-silicate glass

    International Nuclear Information System (INIS)

    Wurth, R.; Pascual, M.J.; Mather, G.C.; Pablos-Martín, A.; Muñoz, F.; Durán, A.; Cuello, G.J.; Rüssel, C.

    2012-01-01

    A base glass of composition 3.5 Li 2 O∙0.15 Na 2 O∙0.2 K 2 O∙1.15 MgO∙0.8 BaO∙1.5 ZnO∙20 Al 2 O 3 ∙67.2 SiO 2 ∙2.6 TiO 2 ∙1.7 ZrO 2 ∙1.2 As 2 O 3 (in wt.%), melted and provided by SCHOTT AG (Mainz), was used to study the crystallisation mechanism of lithium alumino-silicate glass employing X-ray diffraction combined with neutron diffraction and non-isothermal differential scanning calorimetry (DSC). A high-quartz solid solution of LiAlSi 2 O 6 with nanoscaled crystals forms at 750 °C. Quantitative Rietveld refinement of samples annealed at 750 °C for 8 h determined a crystallised fraction of around 59 wt.%. The room temperature crystallised phase adopts an ordered, β-eucryptite-like structure (2 × 2 × 2 cell) with Li ordered in the structural channels. The Avrami parameter (n ∼ 4), calculated from DSC data using different theoretical approaches, indicates that bulk crystallisation occurs and that the number of nuclei increases during annealing. The activation energy of the crystallisation is 531 ± 20 kJ mol −1 . - Highlights: ► Nanoscaled high-quartz crystals from a multicomponent lithium alumino-silicate glass. ► Combined X-ray and neutron diffraction structural refinement. ► β-Eucryptite-like structure (2 × 2×2 cell) with Li ordered in the structural channels. ► 3-Dimensional bulk crystallisation mechanism with an increasing number of nuclei. ► Usage and validation of an alternative approach to calculate the Avrami parameter.

  18. The phase transformation and crystallization kinetics of (1 - x)Li{sub 2}O-xNa{sub 2}O-Al{sub 2}O{sub 3}-4SiO{sub 2} glasses

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Moo-Chin [Department of Fragrance and Cosmetic Science, Kaohsiung Medical University, 100 Shih-Chuan 1st Road, Kaohsiung 807, Taiwan (China); Li, Wang-Long [Institute of Nanotechnology and Microsystems Engineering, National Cheng Kung University, 1 Ta-Hsueh Road, Tainan 70101, Taiwan (China); Cheng, Chih-Wei [Department of Mechanical Engineering, National Kaohsiung University of Applied Sciences, 415 Chien-Kung Road, Kaohsiung 80782, Taiwan (China); Chang, Kuo-Ming; Chen, Yong-Feng [Department of Electrical Engineering, National Cheng Kung University, 1 Ta-Hsueh Road, Tainan 70101, Taiwan (China); Hsi, Chi-Shiung, E-mail: chsi@nuu.edu.tw [Department of Materials Science and Engineering, National United University, 1 Lein-Da, Kung-Ching Li, Miaoli 36003, Taiwan (China)

    2010-09-01

    The phase transformation and crystallization kinetics of (1 - x)Li{sub 2}O-xNa{sub 2}O-Al{sub 2}O{sub 3}-4SiO{sub 2} glasses have been studied by using differential thermal analysis (DTA), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and electron diffraction (ED) analysis. The crystallization temperature at the exothermic peak increases from 1171 to 1212 K when the Na{sub 2}O content increases from 0 to 0.6 mol. The crystalline phase is composed of spodumene crystallization when the Na{sub 2}O content increases from 0 to 0.6 mol. The activation energy of spodumene crystallization decreases from 444.0 {+-} 22.2 to 284.0 {+-} 10.8 kJ mol{sup -1} when the Na{sub 2}O content increases from 0 to 0.4 mol. Moreover, the activation energy increases from 284.0 {+-} 10.8 to 446.0 {+-} 23.2 kJ mol{sup -1} when the Na{sub 2}O content increases from 0.4 to 0.6 mol. The crystallization parameters m and n approach 2, indicating that the surface nucleation and two-dimensional growth are dominant in (1 - x)Li{sub 2}O-xNa{sub 2}O-Al{sub 2}O{sub 3}-4SiO{sub 2} glasses.

  19. The phase transformation and crystallization kinetics of (1 - x)Li2O-xNa2O-Al2O3-4SiO2 glasses

    International Nuclear Information System (INIS)

    Wang, Moo-Chin; Li, Wang-Long; Cheng, Chih-Wei; Chang, Kuo-Ming; Chen, Yong-Feng; Hsi, Chi-Shiung

    2010-01-01

    The phase transformation and crystallization kinetics of (1 - x)Li 2 O-xNa 2 O-Al 2 O 3 -4SiO 2 glasses have been studied by using differential thermal analysis (DTA), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and electron diffraction (ED) analysis. The crystallization temperature at the exothermic peak increases from 1171 to 1212 K when the Na 2 O content increases from 0 to 0.6 mol. The crystalline phase is composed of spodumene crystallization when the Na 2 O content increases from 0 to 0.6 mol. The activation energy of spodumene crystallization decreases from 444.0 ± 22.2 to 284.0 ± 10.8 kJ mol -1 when the Na 2 O content increases from 0 to 0.4 mol. Moreover, the activation energy increases from 284.0 ± 10.8 to 446.0 ± 23.2 kJ mol -1 when the Na 2 O content increases from 0.4 to 0.6 mol. The crystallization parameters m and n approach 2, indicating that the surface nucleation and two-dimensional growth are dominant in (1 - x)Li 2 O-xNa 2 O-Al 2 O 3 -4SiO 2 glasses.

  20. Superplastic ceramics and intermetallics and their potential applications

    International Nuclear Information System (INIS)

    Wadsworth, J.; Nieh, T.G.

    1994-11-01

    Recent advances in the basic understanding of superplasticity and superplastic forming of ceramics and intermetallics are reviewed. Fine-grained superplastic ceramics, including yttria-stabilized tetragonal zirconia polycrystal, Y- or MgO-doped Al 2 O 3 Hydroxyapatite, β-spodumene glass ceramics, Al 2 0 3 -YTZP two-phase composites, SiC-Si 3 N 4 and Fe-Fe 3 C composites, are discussed. Superplasticity in the nickel-base (e.g., Ni 3 Al and Ni 3 Si) and titanium-base intermetallics (TiAl and T1 3 Al), is described. Deformation mechanisms as well as microstructural requirements and effects such as grain size, grain growth, and grain-boundary phases, on the superplastic deformation behavior am addressed. Factors that control the superplastic tensile elongation of ceramics are discussed. Superplastic forming, and particularly biaxial gas-pressure forming, of several ceramics and intermetallics are presented with comments on the likelihood of commercial application

  1. Geologic and radiometric prospect of the mine ''El Muerto'' Oaxaca, Mex

    International Nuclear Information System (INIS)

    Manjarrez C, E.

    1981-01-01

    The studies realized in the mine demonstrated that the uranium mineral inclosure obtained in the pegmatites exists in very little concentrations and does not constitute useful deposits. Therefore, there are found rare earths minerals like monazite and euxenite so the mine may be proficient in the extraction of other type of minerals like spodumene, beryl, etc. Because of the scarce knowledges that we have about the pegmatites referring to the radiactive minerals study, it is stated the necessity of making programs perfectly coordinated and projected in the application of the metallurgic investigation that permits the increase in results of useful value, without to lose sight that the principal objective is to have a real economic, industrial and scientific view of the radiactive minerals localized in the pegmatites, considering the refractory character of the same, and the mineral little volume that in general they contain. (author)

  2. Visualisation of the high-current e-beams on solid surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Solomonov, V I; Osipov, V V; Mikhajlov, S G; Lipchak, A I [Russian Academy of Sciences, Ural Division, Ekaterinburg (Russian Federation). Institute of Electrophysics

    1997-12-31

    Natural minerals such as spodumen, calcite, and Mn-doped apatite crystals may serve as suitable low-cost materials for visualization of high-current electron beams. High-intensity luminescence lasting several tens of minutes has been observed when irradiating natural specimen by electron beams with the current density of 10-1000 A/sq.cm, with energy of 100-300 keV, and pulse duration of 2-50 ns. The luminescent images of the beam cross-section provide information on the beam density profiles, while the images taken in the plane parallel to the beam axis make it possible to estimate the beam penetration depth and, therefore, the beam energy. The method is illustrated by examples of luminescent images taken from the experiment. (J.U.).

  3. Cobalt-Free Permanent Magnet Alloys.

    Science.gov (United States)

    1984-10-01

    ThC Ferrites (Zn, Mn. Cu, Fe)O A12O. Al TiC Kaolin Al203.Si02-Fe2O3 Fe2O3 Li B4C Spodumene LiAI (SiOs) 2 ThO2 Ni UC Rhodonite NtnO. SiO2 MnOs Fe TaC...minutes. X-ray diffraction pattern indicated the presence of magnetic T phase. Hysteresis loop was measured on the heat treated powder dispersed in wax...fmgei * T phse Hysersi loo was mesue on the. heat - treated ,--". " powder dispersed in wax... The’ result wer as"- follows: • , " • "• . I TABLE 6

  4. Rare Mineralogy in Alkaline Ultramafic Rocks, Western Kentucky Fluorspar District

    Science.gov (United States)

    Anderson, W.

    2017-12-01

    The alkaline ultramafic intrusive dike complex in the Western Kentucky Fluorspar District contains unusual mineralogy that was derived from mantle magma sources. Lamprophyre and peridotite petrologic types occur in the district where altered fractionated peridotites are enriched in Rare Earth Elements (REE) and some lamprophyre facies are depleted in incompatible elements. Unusual minerals in dikes, determined by petrography and X-ray diffraction, include schorlomite and andradite titanium garnets, astrophyllite, spodumene, niobium rutile, wüstite, fluoro-tetraferriphlogopite, villiaumite, molybdenite, and fluocerite, a REE-bearing fluoride fluorescent mineral. Mixing of MVT sphalerite ore fluids accompanies a mid-stage igneous alteration and intrusion event consistent with paragenetic studies. The presence of lithium in the spodumene and fluoro-tetraferriphlogopite suggests a lithium phase in the mineral fluids, and the presence of enriched REE in dikes and fluorite mineralization suggest a metasomatic event. Several of these rare minerals have never been described in the fluorspar district, and their occurrence suggests deep mantle metasomatism. Several REE-bearing fluoride minerals occur in the dikes and in other worldwide occurrences, they are usually associated with nepheline syenite and carbonatite differentiates. There is an early and late stage fluoride mineralization, which accompanied dike intrusion and was also analyzed for REE content. One fluorite group is enriched in LREE and another in MREE, which suggests a bimodal or periodic fluorite emplacement. Whole-rock elemental analysis was chondrite normalized and indicates that some of the dikes are slightly enriched in light REE and show a classic fractionation enrichment. Variations in major-element content; high titanium, niobium, and zirconium values; and high La/Yb, Zr/Y, Zr/Hf, and Nb/Ta ratios suggest metasomatized lithospheric-asthenospheric mantle-sourced intrusions. The high La/Yb ratios in some

  5. Crystallisation mechanism of a multicomponent lithium alumino-silicate glass

    Energy Technology Data Exchange (ETDEWEB)

    Wurth, R. [Otto-Schott-Institut, Jena University, Fraunhoferstr. 6, 07743 Jena (Germany); Pascual, M.J., E-mail: mpascual@icv.csic.es [Instituto de Ceramica y Vidrio, CSIC, Kelsen 5, 28049 Madrid (Spain); Mather, G.C.; Pablos-Martin, A.; Munoz, F.; Duran, A. [Instituto de Ceramica y Vidrio, CSIC, Kelsen 5, 28049 Madrid (Spain); Cuello, G.J. [Institut Laue-Langevin, Boite Postale 156, 38042 Grenoble Cedex 9 (France); Ruessel, C. [Otto-Schott-Institut, Jena University, Fraunhoferstr. 6, 07743 Jena (Germany)

    2012-06-15

    A base glass of composition 3.5 Li{sub 2}O Bullet-Operator 0.15 Na{sub 2}O Bullet-Operator 0.2 K{sub 2}O Bullet-Operator 1.15 MgO Bullet-Operator 0.8 BaO Bullet-Operator 1.5 ZnO Bullet-Operator 20 Al{sub 2}O{sub 3} Bullet-Operator 67.2 SiO{sub 2} Bullet-Operator 2.6 TiO{sub 2} Bullet-Operator 1.7 ZrO{sub 2} Bullet-Operator 1.2 As{sub 2}O{sub 3} (in wt.%), melted and provided by SCHOTT AG (Mainz), was used to study the crystallisation mechanism of lithium alumino-silicate glass employing X-ray diffraction combined with neutron diffraction and non-isothermal differential scanning calorimetry (DSC). A high-quartz solid solution of LiAlSi{sub 2}O{sub 6} with nanoscaled crystals forms at 750 Degree-Sign C. Quantitative Rietveld refinement of samples annealed at 750 Degree-Sign C for 8 h determined a crystallised fraction of around 59 wt.%. The room temperature crystallised phase adopts an ordered, {beta}-eucryptite-like structure (2 Multiplication-Sign 2 Multiplication-Sign 2 cell) with Li ordered in the structural channels. The Avrami parameter (n {approx} 4), calculated from DSC data using different theoretical approaches, indicates that bulk crystallisation occurs and that the number of nuclei increases during annealing. The activation energy of the crystallisation is 531 {+-} 20 kJ mol{sup -1}. - Highlights: Black-Right-Pointing-Pointer Nanoscaled high-quartz crystals from a multicomponent lithium alumino-silicate glass. Black-Right-Pointing-Pointer Combined X-ray and neutron diffraction structural refinement. Black-Right-Pointing-Pointer {beta}-Eucryptite-like structure (2 Multiplication-Sign 2 Multiplication-Sign 2 cell) with Li ordered in the structural channels. Black-Right-Pointing-Pointer 3-Dimensional bulk crystallisation mechanism with an increasing number of nuclei. Black-Right-Pointing-Pointer Usage and validation of an alternative approach to calculate the Avrami parameter.

  6. Thermal expansion model for multiphase electronic packaging materials

    International Nuclear Information System (INIS)

    Allred, B.E.; Warren, W.E.

    1991-01-01

    Control of thermal expansion is often necessary in the design and selection of electronic packages. In some instances, it is desirable to have a coefficient of thermal expansion intermediate between values readily attainable with single or two phase materials. The addition of a third phase in the form of fillers, whiskers, or fibers can be used to attain intermediate expansions. To help design the thermal expansion of multiphase materials for specific applications, a closed form model has been developed that accurately predicts the effective elastic properties of isotropic filled materials and transversely isotropic lamina. Properties of filled matrix materials are used as inputs to the lamina model to obtain the composite elastic properties as a function of the volume fraction of each phase. Hybrid composites with two or more fiber types are easily handled with this model. This paper reports that results for glass, quartz, and Kevlar fibers with beta-eucryptite filled polymer matrices show good agreement with experimental results for X, Y, and Z thermal expansion coefficients

  7. Lithium aluminosilicate reinforced with carbon nanofiber and alumina for controlled-thermal-expansion materials

    Directory of Open Access Journals (Sweden)

    Amparo Borrell, Olga García-Moreno, Ramón Torrecillas, Victoria García-Rocha and Adolfo Fernández

    2012-01-01

    Full Text Available Materials with a very low or tailored thermal expansion have many applications ranging from cookware to the aerospace industry. Among others, lithium aluminosilicates (LAS are the most studied family with low and negative thermal expansion coefficients. However, LAS materials are electrical insulators and have poor mechanical properties. Nanocomposites using LAS as a matrix are promising in many applications where special properties are achieved by the addition of one or two more phases. The main scope of this work is to study the sinterability of carbon nanofiber (CNFs/LAS and CNFs/alumina/LAS nanocomposites, and to adjust the ratio among components for obtaining a near-zero or tailored thermal expansion. Spark plasma sintering of nanocomposites, consisting of commercial CNFs and alumina powders and an ad hoc synthesized β-eucryptite phase, is proposed as a solution to improving mechanical and electrical properties compared with the LAS ceramics obtained under the same conditions. X-ray diffraction results on phase compositions and microstructure are discussed together with dilatometry data obtained in a wide temperature range (−150 to 450 °C. The use of a ceramic LAS phase makes it possible to design a nanocomposite with a very low or tailored thermal expansion coefficient and exceptional electrical and mechanical properties.

  8. Percolative ionic conduction in the LiAlSiO4 glass-ceramic system

    International Nuclear Information System (INIS)

    Biefeld, R.M.; Pike, G.E.; Johnson, R.T. Jr.

    1977-01-01

    The effect f crystallinity on the lithium ion conductivity in LiAlSiO 4 glass and glass-ceramic solid electrolytes has been determined. The ionic conductivity is thermally activated with an activation energy and pre-exponential factor that change in a marked and nonsimple manner as the volume fraction of crystallinity changes. These results are explained by using a continuum percolation model (effective-medium approximation) which assumes that ionic conduction in the glass-ceramic is almost entirely within the glass phase until the crystalline volume fraction rises above approx. 55%. The LiAlSiO 4 system would seem to be nearly ideal for application of percolation theory since the crystalline phase, β eucryptite, has nearly the same composition as the glass phase. Hence, as the crystallite volume fraction increases in the glass ceramic, the residual glass composition and conductivity remain the same. This is the first application of percolation theory to ionic transport in glass-ceramics and excellent agreement is obtained between theory and experiment for the LiAlSiO 4 system

  9. Lithium aluminosilicate reinforced with carbon nanofiber and alumina for controlled-thermal-expansion materials

    International Nuclear Information System (INIS)

    Borrell, Amparo; García-Moreno, Olga; Torrecillas, Ramón; García-Rocha, Victoria; Fernández, Adolfo

    2012-01-01

    Materials with a very low or tailored thermal expansion have many applications ranging from cookware to the aerospace industry. Among others, lithium aluminosilicates (LAS) are the most studied family with low and negative thermal expansion coefficients. However, LAS materials are electrical insulators and have poor mechanical properties. Nanocomposites using LAS as a matrix are promising in many applications where special properties are achieved by the addition of one or two more phases. The main scope of this work is to study the sinterability of carbon nanofiber (CNFs)/LAS and CNFs/alumina/LAS nanocomposites, and to adjust the ratio among components for obtaining a near-zero or tailored thermal expansion. Spark plasma sintering of nanocomposites, consisting of commercial CNFs and alumina powders and an ad hoc synthesized β-eucryptite phase, is proposed as a solution to improving mechanical and electrical properties compared with the LAS ceramics obtained under the same conditions. X-ray diffraction results on phase compositions and microstructure are discussed together with dilatometry data obtained in a wide temperature range (−150 to 450 °C). The use of a ceramic LAS phase makes it possible to design a nanocomposite with a very low or tailored thermal expansion coefficient and exceptional electrical and mechanical properties.

  10. Cesium residue leachate migration in the tailings management area of a mine site : predicted vs. actual

    Energy Technology Data Exchange (ETDEWEB)

    Solylo, P.; Ramsey, D. [Wardrop Engineering, Winnipeg, MB (Canada). Mining and Minerals Section

    2009-07-01

    This paper reported on a study at a cesium products facility (CPF) that manufactures a non-toxic cesium-formate drilling fluid. The facility operates adjacent to a pollucite/tantalum/spodumene mine. The CPF was developed as a closed system, with the residue tailings slurry from the CPF process discharged to doublelined containment cells. Groundwater monitoring has shown that leachate has affected near-surface porewater quality within the tailings management area (TMA). Elevated concentrations of calcium, sulphate, strontium, cesium, and rubidium were used to identify the leachate. Porewater at the base of the tailings and in the overburden beneath the tailings has not been affected. A geochemical investigation was initiated to determine how the leachate behaves in the groundwater/tailings porewater system. Over the past 7 years of residue placement in the TMA, the footprint of the residue placement area has changed, making the comparison of predicted versus actual rate of leachate migration very subjective and difficult to quantify. Based solely on the analytical data, the source of the leachate is unknown, either from the original residue pile or the 2007 residue placement area. For purposes of long term residue management, an investigation of the geochemical behaviour of residue leachate in the groundwater/tailings system of the TMA is currently underway. 5 refs., 1 tab., 2 figs.

  11. Crystallization characteristics and physico-chemical properties of glass–ceramics based on Li2O–ZnO–SiO2 system

    Directory of Open Access Journals (Sweden)

    Saad M. Salman

    2017-09-01

    Full Text Available Glass materials based on lithium zinc silicate system of the composition 24Li2O–20ZnO–56SiO2 LZS (mol% were prepared and converted to glass–ceramics using controlled heat-treatment schedules. The LZS base glass system was modified by addition of Al2O3 and MO/ZnO replacements where MO = CaO, CdO and SrO oxides. Several crystalline phases were developed, including lithium zinc orthosilicate, α-quartz, β-spodumene solid solution, lithium meta and disilicate, Ca-wollastonite, Cd or Sr metasilicate, and Sr-zinc silicate of hardystonite type. The effects of crystallization process on some properties, like thermal expansion coefficient (TEC, chemical stability, and density of glass–ceramics were evaluated. The TEC of crystalline samples varied from 72 × 10−7 to 149 × 10−7 K−1, 25–600 and density values in the range, 2.67–3.29 g/cm3. The addition of Al2O3 and MO/ZnO replacements in the base glass led to improve the chemical durability of the glass–ceramics samples. As a result of the thermal and physico-chemical properties of the studied glass–ceramic, the materials acquire excellent properties and can be used to seal a variety of different metals and alloys.

  12. Lithium in the Natural Waters of the South East of Ireland.

    Science.gov (United States)

    Kavanagh, Laurence; Keohane, Jerome; Cleary, John; Garcia Cabellos, Guiomar; Lloyd, Andrew

    2017-05-26

    The South East of Ireland (County Carlow) contains a deposit of the valuable lithium-bearing mineral spodumene (LiAl(SiO₃)₂). This resource has recently attracted interest and abstractive mining in the area is a possibility for the future. The open cast mining of this resource could represent a potential hazard in the form of metalliferous pollution to local water. The population of County Carlow is just under 60,000. The local authority reports that approximately 75.7% of the population's publicly supplied drinking water is abstracted from surface water and 11.6% from groundwater. In total, 12.7% of the population abstract their water from private groundwater wells. Any potential entry of extraneous metals into the area's natural waters will have implications for people in county Carlow. It is the goal of this paper to establish background concentrations of lithium and other metals in the natural waters prior to any mining activity. Our sampling protocol totaled 115 sites along five sampling transects, sampled through 2015. From this dataset, we report a background concentration of dissolved lithium in the natural waters of County Carlow, surface water at x ¯ = 0.02, SD = 0.02 ranging from 0 to 0.091 mg/L and groundwater at x ¯ = 0.023, SD = 0.02 mg/L ranging from 0 to 0.097 mg/L.

  13. Crystallization characteristics and physico-chemical properties of glass–ceramics based on Li2O–ZnO–SiO2 system

    International Nuclear Information System (INIS)

    Salman, Saad M.; Salama, Samia N.; Abo-Mosallam, Hany A.

    2017-01-01

    Glass materials based on lithium zinc silicate system of the composition 24Li2O–20ZnO–56SiO2 LZS (mol%) were prepared and converted to glass–ceramics using controlled heat-treatment schedules. The LZS base glass system was modified by addition of Al2O3 and MO/ZnO replacements where MO=CaO, CdO and SrO oxides. Several crystalline phases were developed, including lithium zinc orthosilicate, α-quartz, β-spodumene solid solution, lithium meta and disilicate, Ca-wollastonite, Cd or Sr metasilicate, and Sr-zinc silicate of hardystonite type. The effects of crystallization process on some properties, like thermal expansion coefficient (TEC), chemical stability, and density of glass–ceramics were evaluated. The TEC of crystalline samples varied from 72×10−7 to 149×10−7K−1, 25–600 and density values in the range, 2.67–3.29g/cm3. The addition of Al2O3 and MO/ZnO replacements in the base glass led to improve the chemical durability of the glass–ceramics samples. As a result of the thermal and physico-chemical properties of the studied glass–ceramic, the materials acquire excellent properties and can be used to seal a variety of different metals and alloys. [es

  14. Surface crystallization in a Li{sub 2}O-ZrO{sub 2}-SiO{sub 2}-Al{sub 2}O{sub 3} glass; Cristalizacao de superficie em vidro do sistema Li{sub 2}O-ZrO{sub 2}-SiO{sub 2}-Al{sub 2}O{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Antonio Pedro Novaes de; Teixeira, Alexandre Henrique Bortolotto; Venturelli, Hugo Henrique, E-mail: bortolotto_teixeira@yahoo.com.br, E-mail: venturellihugo@gmail.com, E-mail: antonio.pedro@ufsc.br [Universidade Federal de Santa Catarina (VITROCER/PGMAT/UFSC), Florianopolis, SC (Brazil). Laboratorio de Materiais Vitroceramicos; Montedo, Oscar Rubem Klegues, E-mail: oscar.rkm@gmail.com [Universidade do Extremo Sul Catarinense (CERTEC/PPGCEM/UNESC), Criciuma, SC (Brazil). Grupo de Pesquisa em Ceramica Tecnica

    2017-04-15

    Growth kinetics of crystallized surface layer in a LZSA glass composition, 11.7Li{sub 2}O·12.6ZrO{sub 2}·68.6SiO{sub 2}·7.1Al{sub 2}O{sub 3} (wt%), was studied. For the production of the LZSA glass, it was used commercial raw materials (Li{sub 2}CO{sub 3}, ZrSiO{sub 4}, SiO{sub 2}, Al{sub 2}O{sub 3}) which were mixed and melted at 1550 °C for 120 min and then poured into a metallic mold. Samples of the obtained glass were cut and subjected to heat treatments at different temperatures (825 - 925 °C) and times (30 - 150 min) for formation and growth of crystalline layer. Cross-sections of the heat-treated samples were ground and polished such that images of the formed crystallized layers could be visualized and measured by microscopy. Results showed that it is possible to obtain LZSA glasses with crystallized layers formed by β-spodumene, zircon and lithium silicate, which present thicknesses between 13 and 665 μ and grow at rates varying from 0.4 to 4.8 μm/min in the studied temperature range. (author)

  15. Solid state reaction in alumina nanoparticles/LZSA glass-ceramic composites

    International Nuclear Information System (INIS)

    Montedo, O.K.; Oliveira, A.N. de; Raupp-Pereira, F.

    2016-01-01

    Full text: The aim of this work is to present results related to solid state reactions on LZSA glass-ceramic composites containing alumina reinforcement nano-particles. A LZSA (Li2O-ZrO2-SiO2-Al2O3) glass-ceramic has been prepared by sintering of powders and characterized. Composites containing 0 to 77 vol.% of alumina nanoparticles (27-43 nm APS, 35 m2.g-1 SSA) and a 16.9Li2O•5.0ZrO2•65.1SiO2•8.6Al2O3 glass-ceramic matrix have been prepared. X-ray diffractometry studies have been performed in order of investigating the solid state reactions occurring in LZSA-based composites. Results of the XRD patterns have been related to the coefficient of thermal expansion (CTE), Young modulus, and dielectric constant, showing that, in comparison with the glass-ceramic composition, the composites showed a decrease of CTE with the alumina concentration increasing, due to the increasing of beta-spodumeness formation (solid solution of beta-spodumene, Li2O.Al2O3.4-10SiO2). The performance of the glass-ceramic was improved with the alumina nano-particles addition, showing potential of using in the preparation of Low Thermal Co-fired Ceramics (LTCC). (author)

  16. CRYSTALLIZATION AND THERMAL EXPANSION CHARACTERISTICS OF In2O3-CONTAINING LITHIUM IRON SILICATE-DIOPSIDE GLASSES

    Directory of Open Access Journals (Sweden)

    S.M. SALMAN

    2011-06-01

    Full Text Available The crystallization characteristics of glasses based on lithium iron silicate (LiFeSi2O6-diopside (CaMgSi2O6 composition with addition of Al2O3 at the expense of Fe2O3 were described. The effect of LiInSi2O6/CaMgSi2O6 replacements was also investigated. The thermal treatment, the crystal phases, and the micro-structural properties of (LiFeSi2O6–CaMgSi2O6 glasses, replacing partial Fe2O3 with Al2O3 and partial CaMgSi2O6 with LiInSi2O6, have been studied by a differential thermal analysis, an X-ray diffraction, and a scanning electron microscopy. The glasses show the intense uniform bulkcrystallization with the fine grained microstructure by increasing the replacement of Al2O3/Fe2O3 and LiInSi2O6/CaMgSi2O6. The crystallizing phases of Ca(Fe,Mg(SiO32, a-LiFe5O8, Li2SiO3, a-SiO2 and CaMgSi2O6 are mostly formed together, in most case, with Li0.6Al0.6Si2.4O6, β-eucryptite solid solution, LiInSi2O6, In2Si2O7, and LiFeSi2O6. The Al2O3 partial replacement increases the transformation temperature (Tg and softening one (Ts for the glasses and the glass-ceramics, and decreases the thermal expansion coefficient (a-value for the glasses. The LiInSi2O6 partial replacement decreases Tg and Ts and increases the a-value for the glasses, while the Al2O3 and LiInSi2O6 partial replacements decrease the a-value for the glassceramics. The crystallization characters of the glasses are correlated to the internal structure, as well as role played by the glass-forming cations. However, the one of the glass-ceramics are mainly attributed to the crystalline phases formed in the material.

  17. Study of lithium extraction from brine water, Bledug Kuwu, Indonesia by the precipitation series of oxalic acid and carbonate sodium

    Science.gov (United States)

    Sulistiyono, Eko; Lalasari, Latifa Hanum; Mayangsari, W.; Prasetyo, A. B.

    2018-05-01

    Lithium is one of the key elements in the development of batteries for electric car applications. Currently, the resources of the world's lithium are derived from brine water and lithium mineral based on spodumene rock. Indonesia which is located in the area of the ring of fire, has potential brine water resources in some area, such as brine water from Bledug Kuwu, Central Java that used in this research. The purposes of this research are to characterize brine water, Bledug Kuwu and to investigate the influence of chemical solvents on Li, Na, K, Ca, Mg, Al, B ion precipitation from brine water. This research was done with 2 times the process of chemical precipitation that runs series as follows: 5 liters of brine water were chemically precipitated using 400 ml of 12.43 N oxalic acid and followed by chemical precipitation using 400 mL of 7.07 N sodium carbonate solutions. Evaporation and filtration processes were also done twice in an effort to separate white precipitate and filtrate. The filtrate was analyzed by ICP-OES and white precipitates (salts) were analyzed by SEM, XRD, and XRF. The result shows that oxalate precipitation process extracted 32.24% Al, 23.42% B, 22.43% Ca, 14.26% Fe, 3.21 % K, 9.86% Na and 14.26% Li, the following process by carbonate precipitation process extracted 98.86% Mg, 73% Ca, 22.53% Li, 82.04% Al, 14.38% B, 12.50% K, 2.27% Na. There is 63.21% lithium is not extracted from the series process. The SEM analysis shows that the structure of granules on the precipitated salts by oxalic acid form gentle cubic-shaped solid. In the other hand, oxalate precipitation followed by sodium carbonate has various particle sizes and the shape of crystals is fragments, prism and cube look like magnesium carbonate, calcium chloride, and calcite's crystal respectively. This is in accordance with XRD analysis that phases of whewellite (CaC2O4.H2O), disodium oxalate (Na2C2O4), magnesite (MgCO3), calcium lithium aluminum (Al1.19 Ca1Li0.81), dolomite (CaCO3

  18. Chemical-mineralogical characterization and Moessbauer spectroscopy of aquamarine from Pedra Azul, Northeast of Minas Gerais

    International Nuclear Information System (INIS)

    Viana, Rubia Ribeiro; Jordt-Evangelista, Hanna; Costa, Geraldo Magela da

    2001-01-01

    Aquamarines from three pegmatites located the vicinities of the Pedra Azul city, Minas Gerais state, were investigated in terms of chemical composition, physical properties and Moessbauer spectroscopy. The small lenticular pegmatite bodies are usually less than 5 m wide and exhibit a conspicuous mineralogical and textural zoning. The last thermal event in these pegmatites, determined by K-Ar method in muscovite, is of Neo proterozoic age, coincident with the late stages of the Brasiliano tectono- metamorphic cycle. Chemical analyses showed that sodium is the alkali with higher contents in the aquamarines, thus enabling their classification as sodic beryls. In zoned samples there is an increase of Fe as well as Mn from center to border, while no systematic variation could be detected for other elements. The specific gravity of 2.72 to 2.80 g/cm 3 is higher than the values determined for samples from other pegmatites of Minas Gerais. The refraction indices are ne=1.569 - 1.579 and NW= 1.573 - 1.581 and the birefringence varies from 0.002 to 0.008. The refraction indices increase with the Be O content. The color of aquamarines varies from medium to light blue, sometimes greenish blue. Moessbauer spectra obtained at room temperature and at 80 K show that Fe 2+ is the main chromophore-ion and suggest that the iron is present in octahedral sites as well as in the structural channels. Moessbauer spectra also indicate that the incorporation of Fe 3+ may cause a shift from deep blue to light blue colors. Based on their aquamarine composition the pegmatites were classified as barren, poor in rare alkalis (Li, Rb, Cs) and therefore little differentiated. The relatively simple mineralogy and the lack of lithium minerals such as lepidolite and spodumene confirm this classification. Thus, the composition of beryl can be used as a tracer for the prospection of pegmatites with different degrees of differentiation and consequently with different types of mineralization. (author)

  19. Complex Diffusion Mechanisms for Li in Feldspar: Re-thinking Li-in-Plag Geospeedometry

    Science.gov (United States)

    Holycross, M.; Watson, E. B.

    2017-12-01

    In recent years, the lithium isotope system has been applied to model processes in a wide variety of terrestrial environments. In igneous settings, Li diffusion gradients have been frequently used to time heating episodes. Lithium partitioning behavior during decompression or cooling events drives Li transfer between phases, but the extent of Li exchange may be limited by its diffusion rate in geologic materials. Lithium is an exceptionally fast diffuser in silicate media, making it uniquely suited to record short-lived volcanic phenomena. The Li-in-plagioclase geospeedometer is often used to time explosive eruptions by applying laboratory-calibrated Li diffusion coefficients to model concentration profiles in magmatic feldspar samples. To quantify Li transport in natural scenarios, experimental measurements are needed that account for changing temperature and oxygen fugacity as well as different feldspar compositions and crystallographic orientation. Ambient pressure experiments were run at RPI to diffuse Li from a powdered spodumene source into polished sanidine, albite, oligoclase or anorthite crystals over the temperature range 500-950 ºC. The resulting 7Li concentration gradients developed in the mineral specimens were evaluated using laser ablation ICP-MS. The new data show that Li diffusion in all feldspar compositions simultaneously operates by both a "fast" and "slow" diffusion mechanism. Fast path diffusivities are similar to those found by Giletti and Shanahan [1997] for Li diffusion in plagioclase and are typically 10 to 20 times greater than slow path diffusivities. Lithium concentration gradients in the feldspar experiments plot in the shape of two superimposed error function curves with the slow diffusion regime in the near-surface of the crystal. Lithium diffusion is most sluggish in sanidine and is significantly faster in the plagioclase feldspars. It is still unclear what diffusion mechanism operates in nature, but the new measurements may impact

  20. Li+ alumino-silicate ion source development for the Neutralized Drift Compression Experiment (NDCX-II)

    International Nuclear Information System (INIS)

    Roy, P.K.; Greenway, W.; Kwan, J.W.; Seidl, P.A.; Waldron, W.

    2011-01-01

    To heat targets to electron-volt temperatures for the study of warm dense matter with intense ion beams, low mass ions, such as lithium, have an energy loss peak (dE/dx) at a suitable kinetic energy. The Heavy Ion Fusion Sciences (HIFS) program at Lawrence Berkeley National Laboratory will carry out warm dense matter experiments using Li + ion beam with energy 1.2-4 MeV in order to achieve uniform heating up to 0.1-1 eV. The accelerator physics design of Neutralized Drift Compression Experiment (NDCX-II) has a pulse length at the ion source of about 0.5 (micro)s. Thus for producing 50 nC of beam charge, the required beam current is about 100 mA. Focusability requires a normalized (edge) emittance ∼2 π-mm-mrad. Here, lithium aluminosilicate ion sources, of β-eucryptite, are being studied within the scope of NDCX-II construction. Several small (0.64 cm diameter) lithium aluminosilicate ion sources, on 70%-80% porous tungsten substrate, were operated in a pulsed mode. The distance between the source surface and the mid-plane of the extraction electrode (1 cm diameter aperture) was 1.48 cm. The source surface temperature was at 1220 C to 1300 C. A 5-6 (micro)s long beam pulsed was recorded by a Faraday cup (+300 V on the collector plate and -300 V on the suppressor ring). Figure 1 shows measured beam current density (J) vs. V 3/2 . A space-charge limited beam density of ∼1 mA/cm 2 was measured at 1275 C temperature, after allowing a conditioning time of about ∼ 12 hours. Maximum emission limited beam current density of (ge) 1.8mA/cm 2 was recorded at 1300 C with 10-kV extractions. Figure 2 shows the lifetime of two typical sources with space-charge limited beam current emission at a lower extraction voltage (1.75 kV) and at temperature of 1265 ± 7 C. These data demonstrate a constant, space-charge limited beam current for 20-50 hours. The lifetime of a source is determined by the loss of lithium from the alumino-silicate material either as ions or as neutral

  1. Isotope age of the rare metal pegmatite formation in the Kolmozero-Voron'ya greenstone belt (Kola region of the Fennoscandian shield): U-Pb (TIMS) microlite and tourmaline dating

    Science.gov (United States)

    Kudryashov, Nikolay; Lyalina, Ludmila; Mokrushin, Artem; Zozulya, Dmitry; Groshev, Nikolay; Steshenko, Ekaterina; Kunakkuzin, Evgeniy

    2016-04-01

    The Kolmozero-Voron'ya greenstone belt is located in the central suture zone, which separates the Murmansk block from the Central-Kola and the Keivy blocks. The belt is represented by volcano-sedimentary rocks of Archaean age of 2.9-2.5 Ga. Rare metal pegmatites (Li, Cs with accessory Nb, Ta, and Be) occur among amphibolite and gabbroid intrusions in the northwestern and southeastern parts of the belt. According to the Rb-Sr data, the age of pegmatites was considered to be 2.7 Ga. Until recently there was no generally accepted point of view on the origin of pegmatites. Now we have isotopic data for a range of rock complexes that could pretend to be parental granites for the rare metal pegmatites. These are granodiorites with the zircon age of 2733±Ma, and microcline and tourmaline granites, which Pb-Pb isochronal age on tourmaline from the tourmaline granite located near the deposit is estimated to be 2520±70 Ma. The pegmatite field of the Vasin Myl'k deposit with the lepidolite--albite--microcline--spodumene--pollucite association is located among amphibolites in the northwestern part of the belt. The deposit is represented by subparallel low-angle zoned veins up to 220 m long and 5 m thick dipping in the southeastern direction at an angle of 10° too 30°. The minerals of the columbite--tonalite group from Vasin Myl'k deposit include microlite, simpsonite, and torolite, and are the oldest among different minerals represented by several generations in pegmatites under consideration. Zircons from the pegmatites are mostly represented by crystals with the structure affected by the action of fluids that put certain restrictions on its use as a geochronometer of the crystallization process. Microlite from the pegmatite taken from the dump of a prospecting drill hole was used for U--Pb (TIMS). The mineral is represented by 0.5--1.0 mm long euhedral octahedral crystals. It is brown in color, and transparent. The microlite crystals were preliminarily cleaned from

  2. Perspectives for Li- and Ta-Mineralization in the Borborema Pegmatite Province, NE-Brazil: A review

    Science.gov (United States)

    Beurlen, Hartmut; Thomas, Rainer; da Silva, Marcelo R. Rodrigues; Müller, Axel; Rhede, Dieter; Soares, Dwight Rodrigues

    2014-12-01

    The increasing strategic importance of Li- and Ta-ores during the last decades due to the strong consumption growth for rechargeable batteries and high temperature and corrosion resistant capacitors reactivated the interest of studies in pegmatite fields around the world, because these rocks supply respectively 25% and 100% of the world consumption in these elements. Research on petrogenetic issues and major and accessory mineral chemistry variations in rare element (REL)-pegmatites of the Borborema Pegmatite Province in Northeast Brazil were tested as tools for the diagnosis of the metallogenetic potential of rare metals in individual pegmatites and in the province as a whole along the last dozen of years. The results allowed to establish the nearly isobaric (3.8 kbar) crystallization conditions of the REL-pegmatites between approximately 580 °C (liquidus) and 400 °C (solidus) from a peraluminous melt saturated in an aquo-carbonic medium to low salinity volatile phase and an immiscible peralkaline flux-enriched (H2O, CO2, F, B, Li etc.) melt fraction, based on melt and fluid inclusion studies. Mineral-chemistry data from 30 selected REL-pegmatites in the province allowed to classify three of them as being of the complex-spodumene or -lepidolite subtype in Černý's classification. Both subtypes are supposed to be potentially fertile, (highly fractionated, and with good chances to bear Li- and Ta-ore concentrations). It was also possible to identify several pegmatitic granite intrusions with textural and lithogeochemical characteristics also found in source granites of REL-pegmatite provinces elsewhere. Preliminary chemical Pb/U/Th geochronological determinations in uraninite and xenotyme crystals of these granites indicate an age of 520 ± 10 Ma and match recently published Ar/Ar in mica and U/Pb ages in columbite-group minerals (CGM) of the REL-pegmatites between 509 and 525 Ma. Mineral-chemistry data from grains of the outer zones of the pegmatites do not

  3. The Use of Tribocharging in the Electrostatic Beneficiation of Lunar Simulant

    Science.gov (United States)

    Trigwell, S.; Captain, J. G.; Arens, E. E.; Captain, J. E.; Quinn, J. W.; Calle, C. I.

    2007-01-01

    Any future lunar base and habitat must be constructed from strong dense materials in order to provide for thermal and radiation protection. Lunar soil may meet this need. Lunar regolith has high concentrations of aluminum, silicon, calcium, iron, sodium, and titanium oxides. Refinement or enrichment of specific minerals in the soil before it is chemically processed may be more desirable as it would reduce the size and energy requirements required to produce the virgin material and it may significantly reduce the process' complexity. Also, investigations into the potential production of breathable oxygen from oxidized mineral components are a major research initiative by NASA. In this study. the objective was to investigate the use of tribocharging to charge lunar simulants and pass them through a parallel plate separator to enrich different mineral fractions. This technique takes advantage of the high Lunar vacuum in which much higher voltages can be used on the separation plates than in air. Additionally, the Lunar g1avity, only being 1/6 that of Earth, allows the particles more separation time between the plates and therefore enhances separation. For the separation studies, two lunar stimulants were used. The first simulant was created in-house, labeled KSC-1. using commercially supplied (sieved to 325 mesh) materials, and was composed of 40 wt. % feldspar ((Na,K,Ca)AlSi3O8;SiO2), 40 wt. % olivine ((Mg,Fe)2SiO4), 10 wt. % ilmenite (FeTiO3). and 10 wt. % spodumene (LiAlSi2O6) (pyroxene). The advantage of the in-house mixture is that the composition can he varied to simulate different soil compositions from different areas on the moon. This simulant was used to show proof-of-concept using the designed separator in air. The second stimulant was JSC-1. used for the vacuum experiments. JSC-1 is principally basalts, containing phases of plagioclase. pyroxene. olivine, and ilmenite. The JSC-1 was sieved to provide a 50-75 micron size range to correlate with the mean

  4. Using a robotics competition to teach about and stimulate enthusiasm for Earth science and other STEM topics

    Science.gov (United States)

    Fike, Hildee; Barnhart, Paul; Brevik, Corinne E.; Brevik, Eric C.; Burgess, Cynthia; Chen, Jundong; Egli, Shawna; Harris, Billy; Johanson, Paul J.; Johnson, Naomi; Moe, Marie; Olsen, Reba

    2016-04-01

    One of the major challenges in recruiting students to careers in STEM (science, technology, engineering, and mathematics) fields is to stimulate enthusiasm about these fields in our youth. BEST (Boosting Engineering Science and Technology) Robotics is a national program in the USA that attempts to recruit junior and senior high school students (ages 13-18) into STEM careers by showing youth how exciting these careers can be by using robotics competitions. The competitions have several aspects, including robot design, software engineering, marketing, public outreach, research into the subject area of the year's tasks, and a set of tasks to be physically performed by the robots that each team builds. The tasks to be performed change every year; therefore, even teams that compete over multiple years must build a new robot each year designed to perform the particular tasks charged to them. Dickinson State University is the home to Blue Hawk BEST, one of the hubs that host the first round of competition for teams hoping to move on to regional, and potentially, national level competition. The tasks for 2015 revolved around a mining theme. The robots needed to be able to replace the filter in an air filtration system, fix broken pipes, mine simulated aggregate, coal, magnetite, bauxite, chalcopyrite, and spodumene, and move core samples. Points were awarded for successful progress toward each task based on the difficulty of the task and the market value of the commodities. While several STEM fields are covered in various aspects of the competition, the 2015 competition includes Earth science in that the students are required to research the history and science of the commodities being mined and learn about ways the commodities are important to their lives and the economy of their particular region. Several awards are handed out to the top performing teams in various categories, including spirit and sportsmanship awards. As teams compete for these awards a raucous

  5. Crystallization characteristics and physico-chemical properties of glass–ceramics based on Li2O–ZnO–SiO2 system; Características de cristalización y propiedades físico-químicas de los materiales vitrocerámicos compuestos a base del sistema Li2O-ZnO-SiO2

    Energy Technology Data Exchange (ETDEWEB)

    Salman, Saad M.; Salama, Samia N.; Abo-Mosallam, Hany A.

    2017-11-01

    Glass materials based on lithium zinc silicate system of the composition 24Li2O–20ZnO–56SiO2 LZS (mol%) were prepared and converted to glass–ceramics using controlled heat-treatment schedules. The LZS base glass system was modified by addition of Al2O3 and MO/ZnO replacements where MO=CaO, CdO and SrO oxides. Several crystalline phases were developed, including lithium zinc orthosilicate, α-quartz, β-spodumene solid solution, lithium meta and disilicate, Ca-wollastonite, Cd or Sr metasilicate, and Sr-zinc silicate of hardystonite type. The effects of crystallization process on some properties, like thermal expansion coefficient (TEC), chemical stability, and density of glass–ceramics were evaluated. The TEC of crystalline samples varied from 72×10−7 to 149×10−7K−1, 25–600 and density values in the range, 2.67–3.29g/cm3. The addition of Al2O3 and MO/ZnO replacements in the base glass led to improve the chemical durability of the glass–ceramics samples. As a result of the thermal and physico-chemical properties of the studied glass–ceramic, the materials acquire excellent properties and can be used to seal a variety of different metals and alloys. [Spanish] Los materiales de vidrio compuestos a base del sistema de silicato de cinc y de litio, de la composición 24Li2O–20ZnO-56SiO2 LZS (mol %), se prepararon y se convirtieron en vitrocerámica con regímenes de tratamiento térmico controlado. El sistema de vidrio de base LZS se modificó mediante la adición de reemplazos de Al2O3 y MO/ZnO, donde MO=óxidos de CaO, CdO y SrO. Se desarrollaron varias fases cristalinas, incluyendo ortosilicato de cinc y de litio, de cuarzo α, solución sólida de espomudeno, metal litio y disilicato, Ca-wollastonita, metasilicato Cd o Sr, y silicato de cinc Sr de tipo hardistonita. Se evaluaron los efectos del proceso de cristalización en algunas propiedades, como el coeficiente de expansión térmica, la estabilidad química y la densidad de las vitrocer

  6. Diffusive Fractionation of Lithium Isotopes in Olivine Grain Boundaries

    Science.gov (United States)

    Homolova, V.; Watson, E. B.

    2012-12-01

    Diffusive fractionation of isotopes has been documented in silicate melts, aqueous fluids, and single crystals. In polycrystalline rocks, the meeting place of two grains, or grain boundaries, may also be a site of diffusive fractionation of isotopes. We have undertaken an experimental and modeling approach to investigate diffusive fractionation of lithium (Li) isotopes by grain boundary diffusion. The experimental procedure consists of packing a Ni metal capsule with predominantly ground San Carlos olivine and subjecting the capsule to 1100C and 1GPa for two days in a piston cylinder apparatus to create a nominally dry, 'dunite rock'. After this synthesis step, the capsule is sectioned and polished. One of the polished faces of the 'dunite rock' is then juxtaposed to a source material of spodumene and this diffusion couple is subject to the same experimental conditions as the synthesis step. Li abundances and isotopic profiles (ratios of count rates) were analyzed using LA-ICP-MS. Li concentrations linearly decrease away from the source from 550ppm to the average concentration of the starting olivine (2.5ppm). As a function of distance from the source, the 7Li/6Li ratio decreases to a minimum before increasing to the background ratio of the 'dunite rock'. The 7Li/6Li ratio minimum coincides with the lowest Li concentrations above average 'dunite rock' abundances. The initial decrease in the 7Li/6Li ratio is similar to that seen in other studies of diffusive fractionation of isotopes and is thought to be caused by the higher diffusivity (D) of the lighter isotope relative to the heavier isotope. The relationship between D and mass (m) is given by (D1/D2) =(m2/m1)^β, where β is an empirical fractionation factor; 1 and 2 denote the lighter and heavier isotope, respectively. A fit to the Li isotopic data reveals an effective DLi of ~1.2x10^-12 m/s^2 and a β of 0.1. Numerical modelling was utilized to elucidate the relationship between diffusive fractionation