WorldWideScience

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. 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

  4. Electronic and optical properties of spodumene gemstone: A theoretical study

    Science.gov (United States)

    de Lima, A. F.; Souza, S. O.; Lalic, M. V.

    2008-03-01

    The spodumene (LiAlSi 2O 6) is a natural silicate with monoclinic structure, interesting for a jewel industry and possible application as a scintillator. In this paper we present the electronic structure and some of the basic optical properties of the pure spodumene crystal, as calculated by the first-principles, density functional based, full potential linear augmented plane wave method.

  5. Superionic conduction in β-eucryptite: inelastic neutron scattering and computational studies.

    Science.gov (United States)

    Singh, Baltej; Gupta, Mayanak Kumar; Mittal, Ranjan; Zbiri, Mohamed; Rols, Stephane; Patwe, Sadequa Jahedkhan; Achary, Srungarpu Nagabhusan; Schober, Helmut; Tyagi, Avesh Kumar; Chaplot, Samrath Lal

    2017-06-14

    β-Eucryptite (LiAlSiO 4 ) is known to show super-ionic conductivity above 700 K. We performed inelastic neutron scattering measurements in β-eucryptite over 300-900 K and calculated the phonon spectrum using classical molecular dynamics (MD) simulations. The MD simulations were used to interpret the inelastic neutron spectra at high temperatures. The calculated diffusion coefficient for Li showed superionic conduction above 1200 K in the perfect crystal. The presence of defects was found to enhance diffusion and lower the temperature for Li diffusion. The calculated trajectory of Li atoms at higher temperatures shows that preferential movement of the Li atom is along the hexagonal c-axis, which is further confirmed by the ab initio calculated activation energy profile for cooperative lithium ion displacements. The inter- and intra-channel correlated motion of Li along the hexagonal c-axis gives the minimum energy pathway for Li ion conduction in LiAlSiO 4 .

  6. 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

  7. 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.

  8. 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

  9. 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)

  10. 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.

    1981-01-01

    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 > 0.1 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

  11. Production and characterization of spodumene dosimetric pellets prepared by a sol–gel route

    International Nuclear Information System (INIS)

    Lima, H.R.B.R.; Nascimento, D.S.; Bispo, G.F.C.; Teixeira, V.C.; Valério, M.E.G.; Souza, S.O.

    2014-01-01

    Spodumene is an aluminosilicate that has shown good results for high-dose TL dosimetry for beta or gamma rays. Due to its chemical composition (LiAlSi 2 O 6 ) it has potential to be used as a neutron dosimeter. The synthetic spodumene is usually produced by solid state reaction and conventional sol–gel, whose shortcomings arise from the need to employ high temperatures and high cost reagents, respectively. Proteic sol–gel method is promising, because it can reduce production costs and the possibility of environmental contamination. This work reports the production of the spodumene by the proteic sol–gel method using edible unflavored gelatin as a precursor. The product is characterized physically and morphologically, and investigated its applicability as a TL dosimeter. Two sets of samples were prepared using different sources of silicon, one with TEOS (Si(OC 3 H 5 ) 4 ) and one with SILICA (SiO 2 ). The materials produced were characterized by X-ray diffraction, differential thermal analysis and thermogravimetry in order to evaluate the structural properties, as well as possible changes in physical or chemical properties depending on the temperature. The production of spodumene was successful, with generation of the crystals in the β-phase with tetragonal structure. Sintered pellets produced from these crystals were irradiated with a 90 Sr– 90 Y source and their TL glow curves were evaluated. Although the samples prepared by the proteic sol–gel method with TEOS presented a lower forming temperature, the samples produced with SILICA showed higher sensitivity to radiation. - Highlights: • β-spodumene can be successfully produced by the proteic sol–gel method. • Sintered pellets produced by the proteic sol–gel method are sensitive to beta rays. • β-spodumene produced by the proteic sol–gel method with SiO 2 is more sensitive to radiation detection than the one produced with TEOS

  12. Effects of β-spodumene on the phase development and densification of alumina/aluminium-titanate composites

    International Nuclear Information System (INIS)

    Manurunga, P.; Low, I.M.; O'Connor, B.H.; Kennedy, S.J.

    2000-01-01

    Full text: Spodumene (Li 2 O.Al 2 O 3 .4SiO 2 ) has a monoclinic α polymorph which is stable under ambient conditions and it transforms irreversibly at 1080 deg C to a tetragonal β polymorph which melts at 1423 deg C. Spodumene has been widely used in the glass and ceramic industry for decades as a lithia-bearing flux and low-expansion filler in whiteware bodies. It is also commonly used for making glasses and ceramics which are harder, smoother, chemical and thermal shock resistant. Recently, spodumene has been used as a liquid-phase sintering aid for the densification of alumina, mullite, and aluminium-titanate (AT). In this paper, we describe the use of dilatometry and high temperature neutron diffraction to study respectively the effect of β-spodumene additions (0-15 wt %) on the densification, and in-situ phase formation and abundances in alumina composites containing 30 wt% at temperatures in the range 1000-1400 deg C. These composites were produced using reaction sintering of alumina and rutile. Determination of relative phase abundances in these materials has been performed using the Rietveld refinement method. Results show that β-spodumene began to decompose by phase separation and partial melting at 1290 deg C, followed by complete melting at 1330 deg C. Formation of AT was observed to occur at 1310 deg C and its abundance increased with temperature. The presence of β-spodumene did not react with alumina or rutile to form additional phases. Up to 5 wt% β-spodumene was involved in the liquid-phase-sintering and densification of the alumina-AT composite. Addition of β-spodumene in excess of 5 wt% resulted in pronounced vitrification which partly recrystallised when cooled to room temperature. The presence of glassy phase has been verified by selected-area diffraction in transmission electron microscopy. Dilatometry results show that the presence of up to 5 wt% β-spodumene resulted in a lower onset of sintering temperature and improved densification

  13. Spodumene bearing pegmatites in the Austroalpine unit (Eastern Alps): Distribution and new geochronological data

    Science.gov (United States)

    Ilickovic, Tanja; Schuster, Ralf; Mali, Heinrich; Petrakakis, Konstantin; Schedl, Albert

    2017-04-01

    In the Austroalpine unit of the Eastern Alps spodumene bearing pegmatites occur heterogeneously distributed over an E-W distance of more than 400 km. They are usually associated with barren pegmatites which crystallisized in Permian time. There a two schools of thought about the genesis of the spodumene bearing pegmatites: Economic geologists bring forward the argument that these pegmatites only develop by fractionation of granitic parent plutons, whereas metamorphic petrologists consider that the barren pegmatites and even some highly fractionated pegmatites are products of anatexis of metapelitic country rocks. In the first case the virtual absence of co-genetic fertile granites in the Austroalpine units render the model problematic, whereas in the second case the formation of suitable Li-enriched pegmatitic melts is not yet understood. A new understanding of the Austroalpine basement through geological mapping and geochronological and geochemical investigations during the past few years gives the opportunity to reinvestigate this problem: In Permian time the Austroalpine unit was affected by lithospheric extension, causing basaltic underplating, high temperature / low pressure metamorphism and intense magmatic activity. The Permian P-T-t path is characterized by heating at slightly decreasing pressure. In an ongoing project additional spodumene bearing pegmatites have been discovered and some of them show temporal and spatial relations to relatively small leucogranitic bodies. New Sm/Nd data prove a Permian age for spodumene bearing pegmatites and leucogranites supporting a genetic relation with the barren pegmatites. Mapping revealed certain relations of pegmatites and distinct country rocks. Units of migmatitic mica schists with lots of interlayed barren pegmatites represent areas with aborted melt generation. In some places the melts accumulate forming inhomogeneous leucogranitic bodies. Examples are the Martell granite (South Tyrol) as well as leucoganites

  14. 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.

  15. 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 (<1 ppm), yielding poor precision, and further study using less depleted samples should be conducted for better age determination. [1] Barros, Renata, Julian F. Menuge and Thomas Zack (2016): "Hints on the Origin and Evolution of Spodumene Pegmatites in Southeast Ireland" Proceedings of the

  16. 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}.

  17. 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

  18. 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.

  19. Color centers of manganese in natural spodumene LiAlSi2O6

    International Nuclear Information System (INIS)

    Schmitz, B.; Lehmann, G.

    1975-01-01

    In natural, manganese containing spodumenes lilac and green color centers are successively formed by ionizing irradiation. The green color centers convert to lilac under visible illumination and are also thermally less stable than the latter. Part of the green color centers already converts into lilac ones spontaneously via tunnel recombination of adjacent electron-hole pairs. EPR measurements show the presence of divalent manganese and its participation in the formation of the color centers. Only manganese in the distorted tetrahedral lattice sites of silicon, trivalent in the lilac and quadrivalent in the green state, can explain the observed optical spectra. Measurements of the luminescence of Mn(II) in both emission and excitation show its presence in two distinctly different environments. With formation of the color centers the luminescence from one of these environments disappears completely. Both emission and excitation spectra from this part of Mn(II) are characteristic for Mn(II) in distorted tetrahedral coordination as shown by the luminescence spectra of Mn(II) in crystals with ZnCl 2- 4 groups of distorted tetrahedral symmetry. (orig.) [de

  20. 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.

  1. Mineralogy and petrograghy of some tin, lithium and beryllium bearing albite-pegmatites near Doade, Galicia, Spain

    NARCIS (Netherlands)

    Hensen, B.J.

    1967-01-01

    The petrography and mineralogy of some Hercynian albite-pegmatites near Doade, Galicia, Spain is described. The mineral assemblage consists of albite, K-feldspar, quartz, muscovite, spodumene, petalite, cassiterite, beryl, columbitetantalite, montebrasite, apatite, eosphorite-childrenite, zircon,

  2. Production and characterization of spodumene dosimetric pellets by prepared by pechini and proteic sol–gel route

    International Nuclear Information System (INIS)

    Lima, Héstia Raíssa Batista Reis; Nascimento, Débora Siqueira; Souza, Susana Oliveira de

    2014-01-01

    Spodumene is an aluminosilicate that has proven suitable for high-dose TL dosimetry of beta or gamma rays. Due to the presence of lithium in its chemical composition (LiAlSi 2 O 6 – β-LAS), it has potential as neutron dosimeter as well. This silicate may be obtained naturally or synthetically. The synthetic LAS has been produced by solid state reaction and conventional sol–gel, whose difficulty arises from the need to employ high temperatures and high cost reagents, respectively. Alternative routes like Pechini and proteic sol–gel methods are promising, because they can reduce production costs and the possibility of environmental pollution. This work aimed at producing spodumene with the proteic sol–gel method using edible unflavored gelatin as a precursor and also with the Pechini method. The products were characterized physically and morphologically, and their applicability as TL dosimeter was investigated, comparing the sensitivity of samples produced by different methods. Two sets of samples were produced using different sources of silicon, tetraethyl orthosilicate (TEOS, Si(C 2 H 5 O) 4 ) and silica (SiO 2 ). The materials produced were characterized by X-ray diffraction and by thermal analysis in order to evaluate their structural properties, as well as possible temperature-dependent changes in physical or chemical properties. The syntherized pellets produced with these crystals were irradiated with a 90 Sr– 90 Y source and their TL glow curves were evaluated. The production of β-LAS was successful by both methods, either using silica or TEOS as a silicon source. The crystals were obtained using much lower temperatures than by methods described in literature. We observed that the method of powder production was critical to develop a radiation detector: the best TL material was the powder produced using silica and the Pechini Method. - Highlights: • β-spodumene can be successful produced by Proteic Sol-Gel and Pechini Methods. • Syntherized

  3. Study of phase development in alumina-spodumene ceramics by high temperature neutron diffraction

    International Nuclear Information System (INIS)

    Gan, B.K.; O'Connor, B.H.

    1999-01-01

    Full text: Melting and crystallisation of minor phases are important in many material systems which contain impurities and/or grain boundary liquid phases. Grain boundary glassy phases are generally not thermodynamically stable, and can devitrify during the sintering process or from other high temperature exposure. Characterising the minor phase assemblage in these types of materials has implications in processing, microstructural design and in-service use, particularly fluctuating thermal environments. An in situ high temperature neutron diffraction (ND) technique was used to follow the phase dynamics on sintering an alumina-spodumene ceramic as well as the crystallisation kinetics of the evolving crystalline phase in real time. The main benefit of using ND analysis in the present work is that it provides bulk specimen character of the material which is important in quantitatively extracting phase composition information. Likewise, most diffraction measurements are conducted with ambient or static temperature data, collected after specimens have been heat-treated and then cooled. Such data may yield misleading information particularly in relation to non-equilibrium phases. Hence dynamic measurements are clearly preferable as a direct means of confirming sintering processes. ND measurements were performed using the High Flux Australian Reactor (HIFAR) neutron source operated by the Australian Nuclear Science and Technology Organisation (ANSTO) at Lucas Heights, NSW, Australia. The ND patterns collected on heating the compacts provided relevant information for optimising materials processing and sintering protocols. Similarly, the ND patterns collected for three specific cooling schemes yielded significant details of evolution and crystallisation of the minor phase. The principal aim was to demonstrate the fundamental influence of the minor crystalline phase (and hence glassy phase) on properties and to manipulate and tailor the phase structure by controlled

  4. Observations on the crystallization of spodumene from aqueous solutions in a hydrothermal diamond-anvil cell

    Science.gov (United States)

    Li, Jianking; Chou, I-Ming; Yuan, Shunda; Burruss, Robert A.

    2013-01-01

    Crystallization experiments were conducted in a new type of hydrothermal diamond-anvil cell (HDAC; type V) using LiAlSi2O6 (S) gel and H2O (W) as starting materials. A total of 21 experiments were performed at temperatures up to 950°C and pressures up to 788 MPa. In the samples with relatively low W/S ratios, many small crystals formed in the melt phase during cooling. In those with high W/S ratios, only a few crystals with smooth surfaces crystallized from the aqueous fluid in the presence of melt droplets, which were gradually consumed during crystal growth, indicating rapid transfer of material from the melt to the crystals through the aqueous fluid. The nucleation of crystals started at 710 (±70)°C and 520 (±80) MPa, and crystal growth ended at 570 (±40)°C and 320 (±90) MPa, with the cooling P-T path within the stability field of spodumene + quartz in the S-W system. The observed linear crystal growth rates in the aqueous phase, calculated by dividing the maximum length of a single crystal by the duration of the entire growth step, were 4.7 × 10−6 and 5.7 × 10−6 cm s−1 for the cooling rates of 0.5 and 1°C min−1, respectively. However, a rapid crystal growth rate of 3.6 × 10−5 cm s−1 in the aqueous fluid was observed when the components were supplied by nearby melt droplets. Our results show that when crystals nucleate in the aqueous fluid instead of the melt phase, there are fewer nuclei formed, and they grow much faster due to the low viscosity of the aqueous fluid, which accelerates diffusion of components for the growth of crystals. Therefore, the large crystals in granitic pegmatite can crystallize directly from aqueous fluids rather than hydrosilicate melt.

  5. 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.

  6. 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.

  7. a comparative study of ree geochemistry in precambrian pegmatites ...

    African Journals Online (AJOL)

    BARTH EKWUEME

    minerals like lepidolite, spodumene, and petalite, which are the major minerals of lithium. Extreme enrichment of. Li in acid rocks (< 100ppm) is a useful indicator of extreme fractionation and also may imply that the rocks sampled are late stage high level products. Of all the rocks analysed, only samples (T13- pegmatite, ...

  8. 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

  9. Medida de tempo para o equilíbrio térmico em cristais de espoduménio Measurement of time for thermal equilibrium in Spodumene crystals

    Directory of Open Access Journals (Sweden)

    Sadao Isotani

    1982-11-01

    Full Text Available Descrição de experimentos de medida de tempo para o equilíbrio térmico em cristais de espodumênio, com espessura de 2mm até 5,4mm, na faixa de temperatura de 100°C a 250°C. Os tempos para o equilíbrio térmico mostram uma correlação linear com a espessura tanto para o aquecimento, como para esfriamento. A diferença nos tempos para o equilíbrio térmico e para o aquecimento e esfriamento é da ordem de 20 segundos.Experiments for measurement of time taken to reach thermal equilibrium in Spodumene crystals — 2mm to 5,4mm thick - in the temperature range 100° to 250°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.

  10. Ultra low and negative expansion glass–ceramic materials ...

    Indian Academy of Sciences (India)

    ... nucleated at 545°C for 4 h and crystallized at 720°C for 2 h which resulted in negative coefficient of thermal expansion [(–) 9 to (–) 2 × 10 − 7 / ∘ C] over the temperature range (30–600°C) due to the formation of -eucryptite while other heating schedule showed the formation of spodumene and lithium aluminium silicates.

  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. Crystallisation Kinetics of a β-Spodumene-Based Glass Ceramic

    Directory of Open Access Journals (Sweden)

    Oscar Rubem Klegues Montedo

    2012-01-01

    Full Text Available LZSA (Li2O-ZrO2-SiO2-Al2O3 glass ceramic system has shown high potential to obtain LTCC laminate tapes at low sintering temperature (<1000°C for several applications, such as screen-printed electronic components. Furthermore, LZSA glass ceramics offer interesting mechanical, chemical, and thermal properties, which make LZSA also a potential candidate for fabricating multilayered structures processed by Laminated Objects Manufacturing (LOM technology. The crystallization kinetics of an LZSA glass ceramic with a composition of 16.9Li2O⋅5.0ZrO2⋅65.1SiO2⋅8.6Al2O3 was investigated using nonisothermal methods by differential thermal analysis and scanning electronic microscopy. Apparent activation energy for crystallization was found to be in the 274–292 kJ⋅mol−1 range, and an Avrami parameter n of 1 was obtained that is compared very favorably with SEM observations.

  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. Rubidium-rich feldspars and associated minerals from the Luolamäki pegmatite, Somero, Finland

    Directory of Open Access Journals (Sweden)

    Teerstra, D.K.

    1998-12-01

    Full Text Available Rubidium feldspar occurs near the core zone of the highly fractionated petalite-subtype Luolamäki granitic pegmatite in intimate intergrowth with other feldspars which are part of a characteristic sequence of alteration of pollucite. Pods of pollucite are cut by 5-20 cm-wide veins of albite, petalite, non-perthitic microcline, lepidolite and quartz, by thinner veins of fine-grained micas and spodumene, and are replaced by metasomatic adularia. Grains of rubidium feldspar occur as a potentially ordered phase in the vein microcline in association with earlier-exsolved albite, and also as late thin (< 5 μm veinlets. Rubidium feldspar also occurs as a potentially disordered phase which crystallized along with metasomatic adularia. Both generations of (Rb,K-feldspar have a similar compositional range, close to the join KAlSi3O8-RbAlSi3O8, typically with up to ~21 wt.% Rb2O (~70 mol.% Rbf and with minor Cs, but neglible Na, Ca, Fe or P. Extreme compositions have 26.0 wt.% Rb2O (89.0 mol.% Rbf and 1.26 wt.% Cs2O (2.8 mol.% Csf. The diffuse compositional gradients from microcline to rubicline are consistent with a solid-state exsolution origin, followed by fluid-assisted textural coarsening which generates distinct phase boundaries. In contrast, metasomatic adularian (Rb,K-feldspar was precipitated at low temperature (250-150°C and fine-scale zoning with variable K/Rb is preserved as a growth feature.

  15. 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

  16. 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)

  17. 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

  18. 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)

  19. The influence of Al{sub 2}O{sub 3}, MgO and ZnO on the crystallization characteristics and properties of lithium calcium silicate glasses and glass-ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Salman, S.M. [Glass Research Department, National Research Centre, El-Behoos St., Dokki, Cairo (Egypt)], E-mail: saadmoghazy@hotmail.com; Darwish, H.; Mahdy, E.A. [Glass Research Department, National Research Centre, El-Behoos St., Dokki, Cairo (Egypt)

    2008-12-20

    The crystallization characteristics of glasses based on the Li{sub 2}O-CaO-SiO{sub 2} eutectic (954 {+-} 4 deg. C) system containing Al{sub 2}O{sub 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{sub 2}O by Al{sub 2}O{sub 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, {alpha}-quartz, diopside, clinoenstatite, wollastonite, {beta}-eucryptite ss, {beta}-spodumene, {alpha}-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{sub 2}O{sub 3}, MgO or ZnO additions. The {alpha}-values of the investigated glasses were ranged from (+18) to (+108) x 10{sup -7} K{sup -1} (25-300 deg. C), while those of the glass-ceramics were (+3) to (+135) x 10{sup -7} K{sup -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{sub 2}O{sub 3} with MgO replacements. The composition containing 11.5 mol% Al{sub 2}O{sub 3} and 6.00 mol% MgO exhibited low thermal expansion values and good chemical durability.

  20. Classification, mineralogical and geochemical variations in pegmatites of the Cape Cross-Uis pegmatite belt, Namibia

    Science.gov (United States)

    Fuchsloch, Warrick C.; Nex, Paul A. M.; Kinnaird, Judith A.

    2018-01-01

    The Pan African aged Damara Orogen in Namibia is host to the Cape Cross-Uis pegmatite belt, one of several NE-trending pegmatite belts which host Li, Nb, Ta and Sn mineralisation. Field mapping and structural analysis of thirty seven pegmatite bodies has shown that the pegmatites intrude along crustal weaknesses such as fold axes and bedding planes, predominantly following the approximate NE orientated regional structural fabric. The lack of deformation together with cross-cutting relationships mapped, suggest that pegmatites were emplaced during post-tectonic extension that resulted from end-orogeny crustal relaxation. Based on mineralogy, geochemistry and ore mineralogy, three groups of pegmatites are distinguished within the Cape Cross-Uis belt. (1) The most common are the unzoned Nb-Ta-Sn type with mineralised alteration areas in the form of greisenised and albitised zones that occur sporadically in the pegmatites in various morphologies. (2) The garnet-tourmaline, crudely zoned pegmatites are slightly less common. They are granite-hosted and differ from other pegmatite types in terms of their low Rb, Sr, Nb, Ta, Sn, Cs (< 30 ppm) but higher REE, U, Th, and Y values. (3) The zoned lithium-bearing pegmatites are rare but the most complex. They are subdivided into two groups: The Li-Nb-Ta-Sn spodumene-bearing pegmatites of the Karlowa swarm and the Li-Nb-Ta-Sn-Be petalite-bearing pegmatites of the Strathmore swarm. They are highly fractionated with typical values of Nb (206 ppm), Ta (185 ppm) and Sn (10,016 ppm). There is no spatial distribution or regional zonation of the pegmatites type relative to granite outcrops within the belt. Contrasting geochemical fractionation patterns and the lower concentrations of REE in pegmatites than in granites suggests that pegmatites resulted from varying degrees of partial melting of a muscovite-ilmenite-bearing source. The Sn, Nb and Ta in pegmatites is likely to have originated from this source rather than from assimilation

  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. Extruded ceramic honeycomb and method

    Science.gov (United States)

    Day, J. Paul

    1995-04-04

    Extruded low-expansion ceramic honeycombs comprising beta-spodumene solid solution as the principal crystal phase and with less than 7 weight percent of included mullite are produced by compounding an extrusion batch comprising a lithium aluminosilicate glass powder and a clay additive, extruding a green honeycomb body from the batch, and drying and firing the green extruded cellular honeycomb to crystallize the glass and clay into a low-expansion spodumene ceramic honeycomb body.

  3. Method of making in-situ whisker reinforced glass ceramic

    Science.gov (United States)

    Brown, Jesse J.; Hirschfeld, Deidre A.; Lee, K. H.

    1993-02-16

    A heat processing procedure is used to create reinforcing whiskers of TiO.sub.2 in glass-ceramic materials in the LAS and MAS family. The heat processing procedure has particular application in creating TiO.sub.2 in-situ in a modified .beta.-eucryptite system.

  4. 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

  5. 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.

  6. Study of gem materials by neutron irradiation: characterization of impurities and color centers

    International Nuclear Information System (INIS)

    Leal, Alexandre S.; Menezes, Maria A.B.C.; Brito, Walter de; D'Urco, Ana F.A.; Felix, Marcia C.; Krambrock, Klaus; Ferreira, Ana F.

    2005-01-01

    Since one-century laboratory irradiation techniques are applied to the color enhancement of gem minerals. Its actual status and applications are discussed. Many different colors in a variety of gem minerals can be produced by gamma, electron and neutron irradiation combined with thermal treatments, however, many color centers and coloration processes are not known in detail. In this work we present examples of neutron irradiation applied to colorless topaz, spodumene and diamond. Topaz and diamond turned blue, spodumene orange. All color centers produced by neutron irradiation are stable to elevated temperatures and can be considered as color enhancing processes. (author)

  7. 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 ...

  8. High temperature flow behaviour of SiC reinforced lithium ...

    Indian Academy of Sciences (India)

    Unknown

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

  9. A search for IRSL-Active dosimeters with enhanced sensitivity : a spectroscopic survey

    DEFF Research Database (Denmark)

    Poolton, N.R.J.; Bøtter-Jensen, L.; Johnson, O.

    1997-01-01

    The spectral and radiation dose characteristics of a range of previously uninvestigated alumine-silicate materials are surveyed, with the intention of searching for alternative, high sensitivity materials that could potentially be used as InfraRed Stimulated Luminescence (IRSL) dosemeters...... for the measurement of environmental doserates. Quartz, petalite, feldspar, leucite, analcite, nephaline, sodalite, tugtupite and alumina were studied and, of this set, only feldspar and alumina were found to be useful. To improve the sensitivity of natural feldspar materials, these were annealed in nitrogen...

  10. Synthesis and Sintering Behavior of Cordierite Prepared from Multi-Component Materials Including Alkaline-Earth Minerals

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Suk-In; Kim, Nam-Il; Lee, Sang-Jin [Mokpo National University, Muan (Korea, Republic of)

    2016-10-15

    Cordierite was synthesized using multi-component materials based on a talc-alumina-clay system. The cordierite sintered at 1360 °C showed a high relative density of 98.8% and a low thermal expansion coefficient of 1.59×10{sup -}6/°C. To study the effect of adding alkaline-earth minerals on the cordierite properties, petalite, potash-feldspar, and dicalcium phosphate were added to the synthesized cordierite. In the case of 9 wt% petalite or potash-feldspar addition, the cordierite was more densified; however, the thermal expansion coefficient and the pyroplasticity index were increased. In particular, a 5 μm thick self-glazed coating was formed with the addition of 9 wt% potash-feldspar. In the case of adding dicalcium phosphate, a glass phase was formed at low temperature and gas bubbles formed at high temperature above 1320 ℃. The cordierite synthesized using multi-component materials is expected to be employed as a material for high thermal shock, dense-microstructure flameware.

  11. 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

  12. 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

  13. 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

  14. Verblendkeramik für dentale Restaurationen aus yttriumstabilisiertem Zirkoniumdioxid sowie Verfahren zu deren Auftrag

    OpenAIRE

    Ehrt, R.; Johannes, M.

    2010-01-01

    The invention relates to veneering ceramics for dental restorations, wherein the framework ceramic is made of yttrium-stabilized zirconium dioxide. The aim of the invention is to develop a translucent veneering ceramic based on lithium disilicate and a method for applying the veneering ceramic for dental restorations made of yttrium-stabilized zirconium dioxide. Said veneering ceramic should not contain any leucite, lithium metasilicate, or ss-spodumene and should have very good chemical resi...

  15. 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.

  16. 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.

  17. 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)(

  18. Comportamiento de la eucriptita a alta temperatura mediante estudio in situ por difracción de Rayos X

    Directory of Open Access Journals (Sweden)

    Torecilas, R.

    2012-06-01

    Full Text Available 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 Li2O:Al2O3:SiO2 contents of 1:1:3 and 1:1:2. The synthesis was prepared using kaolinite, lithium carbonate and TEOS and γ- Al2O3, respectively. High resolution X Ray diffraction characterization was performed at high temperature for both compositions between 25 and 1200 ºC. 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.La eucriptita es un aluminosilicato de litio con peculiares propiedades de expansión térmica: posee expansión negativa, es decir, se contrae con el aumento de la temperatura en una de sus orientaciones cristalográficas. Debido a esta singularidad la eucriptita se utiliza en la fabricación de materiales con coeficiente de expansión térmica (CTE próximo a cero. Para este trabajo, se han sintetizado dos composiciones de eucriptita solución sólida con contenidos en Li2O:Al2O3:SiO2 iguales a 1:1:3 y 1:1:2. La síntesis se ha realizado a partir de caolín, carbonato de litio y TEOS o γ- alúmina respectivamente. Los polvos de las dos composiciones de eucriptita se han caracterizado mediante difracción de Rayos X de alta resolución a alta temperatura entre 25 y 1200 ºC. Se ha estudiado el efecto de la temperatura en la estructura y la composición mediante la determinación de los parámetros de red y la estructura cristalina. Los cambios observados se han relacionado con las variaciones del CTE con la

  19. Pegmatite geology of the Shelby district, North Carolina

    Science.gov (United States)

    Griffitts, Wallace R.

    1957-01-01

    The Shelby district is divided into a northwestern and a southeastern province. The rocks in the southeastern province include various units in the Battleground schist formation and the Yorkville granodiorite. Those in the northwestern province include the Carolina gneiss, with its Shelby gneiss member, and the Toluca quartz monzonite. The Cherryville quartz monzonite forms a batholith that is just west of the boundary between the two provinces. Pegmatites related to both the Toluca and the Cherryville quartz monzonites lie in the Carolina gneiss and many dikes of pegmatite that are related to the Cherryville quartz monzonite are in the tin-spodumene belt that lies along the boundary between provinces. The rocks of the southeastern province have been bent into steep isoclinal folds; those of the northwestern province were bent into open folds and gently-dipping isoclinal folds. The rocks to the southeast have been metamorphosed in the epidote-amphibolite facies whereas the rocks to the northwest represent the amphibolite or granulite facies. The pegmatites related to the Toluca quartz monzonite form sills, dikes, and concordant lenses in the Carolina gneiss, as well as dikes in the Toluca quartz monzonite. The bodies are unzoned and consist mainly of gneissic microcline-plagioclase-quartz pegmatite. The pegmatites related to the Cherryville quartz monzonite form dikes and disconformable lenses in the Carolina gneiss and the Toluca quartz monzonite. These pegmatites range widely in composition and many are zoned. The dikes west of the Cherryville batholith are rich in muscovite and plagioclase and may contain no microcline or only a moderate amount of microcline. Quartz cores and microcline-rich intermediate zones are common. Similar pegmatite forms dikes along the west edge of the tin-spodumene belt. The tin-spodumene belt containes albite-microcline-spodumene-quartz pegmatite. These dikes of albitic pegmatite are largest and most nearly parallel to one another

  20. 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.

  1. 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.

  2. 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.

  3. 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

  4. 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)

  5. Petrography and geochemistry of the primary ore zone of the Kenticha rare metal granite-pegmatite field, Adola Belt, Southern Ethiopia: Implications for ore genesis and tectonic setting

    Science.gov (United States)

    Mohammedyasin, Mohammed Seid; Desta, Zerihun; Getaneh, Worash

    2017-10-01

    The aim of this work is to evaluate the genesis and tectonic setting of the Kenticha rare metal granite-pegmatite deposit using petrography and whole-rock geochemical analysis. The samples were analysed for major elements, and trace and rare earth elements by ICP-AES and ICP-MS, respectively. The Kenticha rare metal granite-pegmatite deposit is controlled by the N-S deep-seated normal fault that allow the emplacement of the granite-pegmatite in the study area. Six main mineral assemblages have been identified: (a) alaskitic granite (quartz + microcline + albite with subordinate muscovite), (b) aplitic layer (quartz + albite), (c) muscovite-quartz-microcline-albite pegmatite, (d) spodumene-microcline-albite pegmatite, partly albitized or greisenized, (e) microcline-albite-green and pink spodumene pegmatite with quartz-microcline block, which is partly albitized and greisenized, and (f) quartz core. This mineralogical zonation is also accompanied by variation in Ta ore concentration and trace and rare earth elements content. The Kenticha granite-pegmatite is strongly differentiated with high SiO2 (72-84 wt %) and enriched with Rb (∼689 ppm), Be (∼196 ppm), Nb (∼129 ppm), Ta (∼92 ppm) and Cs (∼150 ppm) and depleted in Ba and Sr. The rare earth element (REE) patterns of the primary ore zone (below 60 m depth) shows moderate enrichment in light REE ((La/Yb)N = ∼8, and LREE/HREE = ∼9.96) and negative Eu-anomaly (Eu/Eu* = ∼0.4). The whole-rock geochemical data display the Within Plate Granite (WPG) and syn-Collisional Granite (syn-COLG) suites and interpret as its formation is crustal related melting. The mineralogical assemblage, tectonic setting and geochemical signatures implies that the Kenticha rare metal bearing granite pegmatite is formed by partial melting of metasedimentary rocks during post-Gondwana assembly and further tantalite enrichment through later hydrothermal-metasomatic processes.

  6. 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.

  7. 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.

  8. 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

  9. Sintesis Zeolit dari Abu Layang dengan Metode Hidrotermal dan Uji Adsorptivitas Terhadap Logam Timbal (Pb

    Directory of Open Access Journals (Sweden)

    Rismang Rismang

    2017-12-01

    Full Text Available Synthesis of zeolite from fly ash obtained from Jeneponto Bosowa energypower plant have been conducted by hydrothermal method. This study was conducted to determine the characteristics of a synthetic zeolite fly ash and synthetic zeolite adsortivitas to metallic lead (Pb. Fly ash which is the main source of silica prepared by the process of concentration variations reflux with HCl (2M; 3M; 4M and 5M. Manufacture of sodium silicate solution by dissolving NaOH fly ash into the proportion of 10 ml per 1 gram of fly ash. Synthesis process by adding sodium aluminate into a solution of sodium silicate with a ratio of 1: 1 and then put in an autoclave as a hydrothermal process at a temperature of 120 ° C for 2 hours. Hydrothermal product obtained is characterized by X-Ray Diffraction (XRD to determine the type and intensity of the zeolite crystals obtained from the synthesis process. XRD analysis results showed the highest intensities are in the process of reflux 5M with type zeolite obtained in the form of zeolite ITQ-34, zeolite (K, Ba -G, L, sodalite and alumina-silica minerals such as eucryptit and aluminum oxide. The resulting zeolite able to absorb the metals Pb2+ at 99.04%, which is made with a concentration of 20 ppm of 50 mL with a mass of 1 gram of zeolite.

  10. Self-diffusion of lithium in LiAlSi2O6 glasses studied using mass spectrometry.

    Science.gov (United States)

    Welsch, A-M; Behrens, H; Horn, I; Ross, S; Heitjans, P

    2012-01-12

    In order to improve our understanding of the transport mechanisms of lithium in glasses, we have performed diffusion and ionic conductivity studies on spodumene composition (LiAlSi(2)O(6)) glasses. In diffusion couple experiments pairs of chemically identical glasses with different lithium isotopy (natural Li vs pure (7)Li) were processed at temperatures between 482 and 732 K. Profiles of lithium isotopes were measured after the diffusion runs innovatively applying femtosecond UV laser ablation combined with inductively coupled plasma mass spectrometry (LA ICP-MS). Self-diffusion coefficients of lithium in the glasses were determined by fitting the isotope profiles. During some of the diffusion experiments the electrical conductivity of the samples was intermittently measured by impedance spectrometry. Combining ionic conductivity and self-diffusivity yields a temperature-independent correlation factor of ~0.50, indicating that motions of Li ions are strongly correlated in this type of glasses. Lithium self-diffusivity in LiAlSi(2)O(6) glass was found to be very similar to that in lithium silicate glasses although Raman spectroscopy demonstrates structural differences between these glasses; that is, the aluminosilicate is completely polymerized while the lithium silicate glasses contain large fractions of nonbridging oxygen.

  11. Mapeamento geológico do Pegmatito Alto do Tibiri: aspectos estruturais e mineralógicos

    Directory of Open Access Journals (Sweden)

    Paulo Jedean da Silva Araújo

    2017-05-01

    Full Text Available The Alto Tibiri is a pegmatite body located in the southern region of the Rio Grande do Norte, in Parelhas city, geologically inserted in the Borborema Pegmatite Province and occur intruding the mica schists of the Seridó Formation. Currently, both mica and feldspar are commercially exploited in this pegmatite body. In the field missions, 39 outcrops were described, in each one the main texture and mineralogical aspects of the outcropping rock were described. The geological mapping has allowed us to distinguish two types of schists, based on content and size of the mineral phases. There is a garnet rich schists and other with a relevant cordierite content. The studied region shows narrow pegmatite dykes, composed of quartz, feldspar, muscovite and/or biotite and black tourmaline, these dikes were classified as homogeneous. It’s possible to observe in Alto Tibiri a well- defined mineral zoning, as follows: i border area, marked by the abundance of muscovite; ii Zone II, composed of quartz, feldspar and mica, in which the main mineral resources occur (tantalite, spodumene, apatite, etc. and iii quartz pockets. The observed mineral zoning is similar to that described as mixed traditional pegmatite bodies.

  12. Color Dependence on Thickness in Topaz Crystal from Brazil

    Directory of Open Access Journals (Sweden)

    Waldemar Bonventi Jr

    2012-01-01

    Full Text Available It is well known that crystals of topaz from the Eastern Brazilian Pegmatite Province may turn blue by the irradiation with 60Co gamma rays followed by heat treatment. Also, it is known that the sensation of color changes with the thickness of these crystals. The dependence of the color, given by 1931 CIE chromaticity coordinates, with the thickness of the crystal was analyzed. The absorbance used in the calculation of these coordinates was given by the sum of Gaussian lines. The parameters of these lines were determined through the decomposition of the optical absorption spectra in the ultraviolet and visible regions. The decomposition revealed several lines, whose assignment was made considering studies in spodumene and beryl crystals and highly accurate quantum mechanical calculations. The transmittance becomes very narrow with increasing thickness, and the CIE chromaticity coordinates converge to the borderline of the CIE Chromaticity Diagram at the wavelength of maximum transmittance. Furthermore, the purity of color increases with increasing thickness, and the dominant wavelength reaches the wavelength of maximum transmittance.

  13. 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.

  14. Microstructure and properties of LZSA glass-ceramic foams

    Energy Technology Data Exchange (ETDEWEB)

    Sousa, E. de [Graduate Program on Materials Science and Engineering-PGMAT, Federal University of Santa Catarina-UFSC, P.O. Box 476, 88040-900 Florianopolis, SC (Brazil); Rambo, C.R. [Graduate Program on Materials Science and Engineering-PGMAT, Federal University of Santa Catarina-UFSC, P.O. Box 476, 88040-900 Florianopolis, SC (Brazil); Department of Chemical Engineering-EQA, Federal University of Santa Catarina-UFSC, P.O. Box 476, 88040-900 Florianopolis, SC (Brazil)], E-mail: Rambo@enq.ufsc.br; Hotza, D. [Graduate Program on Materials Science and Engineering-PGMAT, Federal University of Santa Catarina-UFSC, P.O. Box 476, 88040-900 Florianopolis, SC (Brazil); Department of Chemical Engineering-EQA, Federal University of Santa Catarina-UFSC, P.O. Box 476, 88040-900 Florianopolis, SC (Brazil); Oliveira, A.P. Novaes de [Graduate Program on Materials Science and Engineering-PGMAT, Federal University of Santa Catarina-UFSC, P.O. Box 476, 88040-900 Florianopolis, SC (Brazil); Department of Mechanical Engineering-EMC, Federal University of Santa Catarina-UFSC, P.O. Box 476, 88040-900 Florianopolis, SC (Brazil); Fey, T.; Greil, P. [Department of Materials Science, Glass and Ceramics, University of Erlangen-Nuremberg, Martensstrasse 5, D-91058 Erlangen (Germany)

    2008-03-15

    Commercial polyurethane foams with a monomodal pore size distribution were used to produce LZSA glass-ceramic foams by the polymeric sponge method. A suspension containing LZSA glass powder, bentonite and sodium silicate was prepared in isopropanol to impregnate the polymeric foams by dip coating. The sintering conditions were varied in the range of 700-850 deg. C for 30-180 min. The cellular microstructure of glass-ceramic foams was characterized by scanning electron microscopy (SEM) and micro-computer X-ray tomography ({mu}CT). Optimum physical, mechanical and fluidynamic properties of the LZSA glass-ceramic foams were obtained at 750 deg. C for 60 min. Main crystalline phases detected were {beta}-spodumene and zirconium silicate. The compressive strength of the foams (0.1-10 MPa) is strongly dependent on their overall porosity and their behaviour could be explained using the Gibson-Ashby model. The Darcyan permeability of LZSA foams was found to be in the range of 0.1-4 x 10{sup -9} m{sup 2}, which is in the order of magnitude of cellular supports for aerosol filters, and, therefore, suitable for several other technological applications.

  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. 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)

  17. Propiedades mecánicas y coeficiente de dilatación térmica de la β-eucriptita sinterizada por la técnica de microondas

    Directory of Open Access Journals (Sweden)

    Benavente, R.

    2014-06-01

    Full Text Available Microwave non-conventional sintering technique allows obtaining fully dense glass-free β-eucryptite bulk material (∼99 %. A considerable difference in the densification, microstructure, coefficient of thermal expansion behaviour and mechanical properties, between conventional and non-conventional sintered specimens was observed. The hardness and Young’s modulus values obtained by microwaves at 1200 °C-5min have been relatively high, 6.8 GPa and 101 GPa, respectively, compared to conventional sintering (3.9 GPa and 58 GPa, respectively. Very low thermal expansion materials have been obtained in a wide temperature range including cryogenic temperatures (from -150 ºC to 150 ºC. The high heating rate along with the lower energy consumption makes microwave technique a clear alternative to other types of sintering methods.La técnica de sinterización no convencional de microondas permite obtener materiales de β-eucriptita en estado sólido cristalino con densidades cercanas a la teórica (∼99 %. Se ha observado una diferencia considerable en estos materiales respecto a la técnica convencional en términos de densificación, microestructura, coeficiente de expansión térmica y propiedades mecánicas. Los valores de dureza y módulo de Young obtenidos mediante sinterización por microondas a 1200 ºC-5 min han sido relativamente altos, 6.8 GPa y 101 GPa, respectivamente, en comparación con el material obtenido mediante horno convencional (3.9 GPa y 58 GPa, respectivamente. Los datos dilatométricos obtenidos, incluyendo el intervalo de temperatura criogénica (-150 ºC a +150 ºC, muestran un coeficiente de expansión térmica controlado y negativo en todo el rango de temperaturas. La combinación de un calentamiento rápido junto con la reducción drástica en el tiempo de ciclo y el ahorro energético, hace que la técnica de microondas sean una clara alternativa a otro tipo de calentamientos

  18. 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.

  19. Classification, U-Pb (TIMS) age and sources of the Kolmozero-Keivy rare-element pegmatites (NE Baltic Shield)

    Science.gov (United States)

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

    2017-04-01

    Kolmozero-Keivy zone, NE Baltic shield, is composed mainly from basic-intermediate-acid metavolcanic suites of 2.83-2.87 Ga age and metamorphosed at amphibolitic facies during 1.8-1.7 Ga. Younger igneous events are represented by voluminous intrusions of 2.73 Ga plagio-microcline granites and of 2.65 Ga peralkaline A-type granites, and small stocks of 2.52 Ga tourmaline granites. Four pegmatite fields with total amount of more than 100 bodies are confined to Kolmozero subzone. The pegmatites intrude amphibolites and rarely associated gabbro-anorthosite and are of 50-700m long and of 10-35m thickness. The Kolmozero pegmatites are of complex type, spodumene subtype with Li, Cs, Be, Ta, Sn geochemical signature and belong to LCT family by classification of Cerny and Ercit [1]. They crystallized at relatively high pressure (3-4 kbar) with peralumunious S-type granite as the source magma. The Vasin Myl'k pegmatite field with the lepidolite-albite-microcline-spodumene-pollucite association is located among amphibolites in the northwestern part of the Kolmozero zone. The minerals of the columbite-tantalite group from Vasin Myl'k field include microlite, simpsonite, and torolite, and are the earliest within the rare-element mineral sequence. Microlite from the pegmatite taken from the dump of a prospecting drill hole was used for U-Pb (TIMS) age determination. The discordia constructed for seven measured microlite samples is characterized by upper intercept with concordia at 2454±8 Ma, which probably reflects the time of rare-element pegmatite crystallization, coeval with the age of tourmaline granites. Several tens of pegmatite bodies from Keivy subzone are confined to inner and outer apical parts of peralkaline granite intrusions. They are of few tens meters long and of several meters thickness, sometimes are of oval and irregular shape (so-called quartzolites). Keivy pegmatites are subdivided on quartz-microcline, quartz-feldspar-astrophylite and quartz

  20. Novos fundentes para produção da porcelana de ossos New fluxes for the production of bone china

    Directory of Open Access Journals (Sweden)

    M. P Ballvé

    2010-03-01

    Full Text Available O uso de fundentes enérgicos "alternativos" foi investigado em uma formulação de porcelana de ossos em ciclo de queima rápida. As propriedades dos corpos-de-prova foram avaliadas em diferentes formulações, variando-se o tipo de fundente. A wolastonita, o espodumênio e o pó de vidro foram empregados, substituindo-se parcialmente um feldspato potássico. Os resultados da caracterização tecnológica, formações de fases e microestrutura foram comparados em diferentes temperaturas. Os fundentes utilizados propiciaram uma redução na temperatura final de queima e ao mesmo tempo um amplo intervalo de gresificação. Os resultados da caracterização tecnológica das peças, após a queima das formulações propostas, mostraram que as propriedades técnicas são compatíveis com os produtos porcelânicos almejados.Strong fluxes were investigated in a bone china composition by applying a fast firing cycle. The technical properties of the ceramic bodies were evaluated. The conventional flux (potash feldspar was partially replaced by strong fluxes (wollastonite or spodumene or waste glass. A comparative analysis of the data, including technical properties, microstructure, and phase's development at different firing temperature was performed. Due to the utilization of these strong fluxes, a reduction of firing temperature and, simultaneously, a broad firing range was achieved. Then, the main technical aspects concerning the firing of these new compositions were investigated. The final properties of the pieces were considered good for the production of bone china.

  1. Contribution of di- and trivalent oxides to crystal phase formations and properties of yttrium aluminosilicate glass-ceramics

    Directory of Open Access Journals (Sweden)

    Saad M. Salman

    2015-09-01

    Full Text Available The crystallization behaviour, phase composition, microhardness and chemical durability of some silicate glasses and glass-ceramics based on LiAlSi2O6-YAlSiO5 system were investigated. The effects of partial replacements of LiAlSi2O6 mostly with LiFeSi2O6 and complete replacement of YAlSiO5 with CaMgSi2O6 were considered. In some cases small amount of Cr2O3 was introduced as nucleating agent or Fe2O3 was partially replaced with chromium or indium oxides. The main crystalline phases formed after controlled heat-treatments of the glasses were yttrium-containing β-spodumene solid solution (ss - Li(Al,YSi2O6, together with varieties of pyroxene-ss including lithium iron pyroxene-ss - LiFeSi2O6-CaMgSi2O6, augite ' Ca(Mg,FeSi2O6, chromoaugitess, Li-aegirine - LiFeSi2O6, diopside - CaMgSi2O6 and lithium indium silicate - LiInSi2O6 phases. The Vickers’ microhardness values of the studied glasses (ranged from 4610 to 6185 MPa were greatly affected by the modifications of the glass compositions. On the other hand, the glass-ceramics’ microhardness (7245–8175 MPa was markedly improved depending on the microstructure and the nature of crystalline phases formed. The glass-ceramics have chemical stability better than those for the corresponding glasses.

  2. 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

  3. Lithium isotope fractionation by diffusion in minerals Part 2: Olivine

    Science.gov (United States)

    Richter, Frank; Chaussidon, Marc; Bruce Watson, E.; Mendybaev, Ruslan; Homolova, Veronika

    2017-12-01

    Recent experiments have shown that lithium isotopes can be significantly fractionated by diffusion in silicate liquids and in augite. Here we report new laboratory experiments that document similarly large lithium isotopic fractionation by diffusion in olivine. Two types of experiments were used. A powder-source method where lithium from finely ground spodumene (LiAlSi2O6) diffused into oriented San Carlos olivine, and piston cylinder annealing experiments where Kunlun clinopyroxene (∼30 ppm lithium) and oriented San Carlos olivine (∼2 ppm lithium) were juxtaposed. The lithium concentration along traverses across the run products was measured using both laser ablation as a source for a Varian 820-MS quadrupole mass spectrometer and a CAMECA 1270 secondary ion mass spectrometer. The CAMECA 1270 was also used to measure the lithium isotopic fractionation across olivine grains recovered from the experiments. The lithium isotopes were found to be fractionationed by many tens of permil in the diffusion boundary layer at the grain edges as a result of 6Li diffusing significantly faster than 7Li. The lithium concentration and isotopic fractionation data across the olivine recovered from the different experiments were modeled using calculations in which lithium was assumed to be of two distinct types - one being fast diffusing interstitial lithium, the other much less mobile lithium on a metal site. The two-site diffusion model involves a large number of independent parameters and we found that different choices of the parameters can produce very comparable fits to the lithium concentration profiles and associated isotopic fractionation. Because of this nonuniqueness we are able to determine only a range for the relative diffusivity of 6Li compared to 7Li. When the mass dependence of lithium diffusion is parameterized as D6Li /D7Li =(7 / 6) β , the isotope fractionation for diffusion along the a and c crystallographic direction of olivine can be fit by β = 0.4 ± 0

  4. Comparative Fluid Inclusion Chemistry of Miarolitic Pegmatites from San Diego County, California, USA

    Science.gov (United States)

    Nymberg, D.; Sirbescu, M. L. C.

    2014-12-01

    Miarolitic Li-Cs-Ta pegmatites are an important source of gemstones such as tourmaline var. elbaite and spodumene var. kunzite, but the distribution of gem-bearing pegmatites within a pegmatite field is not understood. This microthermometry, LA-ICP-MS, Raman spectroscopy, and crush-leach study of fluid inclusions in pegmatite quartz aims to discern the chemical variations of late-stage pegmatite fluids in relation to gem mineralization. We studied five mines from three San Diego Co. districts: Chihuahua Valley (C), Jacumba (J), and Pala (P). The ~100 Ma old, 1-10 m thick, subparallel magma sheets intruded plutons of the Peninsular Ranges Batholith or prebatholitic metasediments at an estimated pressure of 200-300 MPa. The pegmatites formed sequentially, from outer zones with comb, layered, and graphic quartz-feldspar textures at the magmatic stage to massive cores and miarolitic pockets at a late, fluid-saturated stage. Pocket quartz was analyzed from pegmatites of variable host rock, magmatic mineral assemblages, and known gem production. The inclusions contained two-phase aqueous fluids and no CO2 or other gases. Fluid salinity ranged from 0.5 to 8.6 wt.% NaCl eq. and correlated positively with inclusion homogenization temperature. Isochoric T at 250 MPa calculated for primary and pseudosecondary inclusions in pocket quartz ranged from 280 to 500 °C in district P, 310-420°C in J, and 230-290°C in C. We attribute the higher T of pocket formation in districts P and J to higher surrounding T at emplacement caused by proximity to other dikes. This preliminary study suggests that gem elbaite and/or kunzite occurrence correlates to Li and B contents in the pocket fluid, which, in turn, are a function of consumption by early, magmatic minerals. The P district has a simple leucogranite mineralogy at the magmatic stage; has as much as 5760 ppm B and 4950 ppm Li in the pocket fluid; and produced both elbaite and kunzite. The J district has abundant magmatic tourmaline

  5. Mineralogical and geochemical characteristics of the Archaean LCT pegmatite deposit Cattlin Creek, Ravensthorpe, Western Australia

    Science.gov (United States)

    Bauer, Matthias; Dittrich, Thomas; Seifert, Thomas; Schulz, Bernhard

    2014-05-01

    The LCT (lithium-cesium-tantalum) pegmatite Cattlin Creek is located about 550 km ESE of Perth, Western Australia. The complex-type, rare-element pegmatite is hosted in metamorphic rocks of the Archaean Ravensthorpe greenstone belt, which constitutes of the southern edge of the Southern Cross Terranes of the Yilgarn Craton. The deposit is currently mined for both lithium and tantalum by Galaxy Resources Limited since 2010. The pegmatitic melt intruded in a weak structural zone of crossing thrust faults and formed several pegmatite sills, of which the surface nearest mineralized pegmatite body is up to 21 m thick. The Cattlin Creek pegmatite is characterized by an extreme fractionation that resulted in the enrichment of rare elements like Li, Cs, Rb, Sn and Ta, as well as the formation of a vertical zonation expressed by distinct mineral assemblages. The border zone comprises a fine-grained mineral assemblage consisting of albite, quartz, muscovite that merges into a medium-grained wall zone and pegmatitic-textured intermediate zones. Those zones are manifested by the occurrence of megacrystic spodumene crystals with grain sizes ranging from a couple of centimeters up to several metres. The core zone represents the most fractionated part of the pegmatite and consists of lepidolite, cleavelandite, and quartz. It also exhibits the highest concentrations of Cs (0.5 wt.%), Li (0.4 wt.%), Rb (3 wt.%), Ta (0.3 wt.%) and F (4 wt.%). This zone was probably formed in the very last crystallization stage of the pegmatite and its minerals replaced earlier crystallized mineral assemblages. Moreover, the core zone hosts subordinate extremely Cs-enriched (up to 13 wt.% Cs2O) mineral species of beryl. The chemical composition of this beryl resamples that of the extreme rare beryl-variety pezzotaite. Other observed subordinate, minor and accessory minerals comprise tourmaline, garnet, cassiterite, apatite, (mangano-) columbite, tantalite, microlite (Bi-bearing), gahnite, fluorite

  6. 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

  7. 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

  8. 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

  9. Voloshinite, a new rubidium mica from granitic pegmatite of Voron'i Tundras, Kola Peninsula, Russia

    Science.gov (United States)

    Pekov, I. V.; Kononkova, N. N.; Agakhanov, A. A.; Belakovsky, D. I.; Kazantsev, S. S.; Zubkova, N. V.

    2010-12-01

    Voloshinite, a new mineral of the mica group, a rubidium analogue of lepidolite, has been found from the rare-element granitic pegmatite at Mt. Vasin-Myl'k, Voron'i Tundras, Kola Peninsula, Russia. It is closely associated with pollucite and lepidolite and commonly with muscovite, albite, and quartz; K,Rb-feldspar, rubicline, spodumene, montebrasite, and elbaite are among associated minerals as well. Voloshinite, a late mineral that formed after pollucite, commonly fills polymineralic veinlets and pods within the pollucite aggregates. It occurs as rims up to 0.05 mm thick around lepidolite, as intergrowths of tabular crystals up to 0.25 mm in size, and occasionally replaces lepidolite. The new mineral is colorless, transparent, with vitreous luster. Cleavage is eminent parallel to {001}; flakes are flexible. The calculated density is 2.95 g/cm3. The new mineral is biaxial (-), with 2 V = 25°, α calc = 1.511, β = 1.586, and γ = 1.590. The optical orientation is Y = b, Z = a. The chemical composition of the type material determined by electron microprobe (average of five point analyses; Li has been determined with ICP-OES) is as follows (wt %): 0.03 Na2O, 3.70 K2O, 12.18 Rb2O, 2.02 Cs2O, 4.0 Li2O, 0.03 CaO, 0.02 MgO, 0.14 MnO, 21.33 Al2O3, 53.14 SiO2, 6.41 F, -O = F2 2.70, total is 100.30. The empirical formula is: (Rb0.54K0.33Cs0.06)Σ0.93(Al1.42Li1.11Mn0.01)Σ2.54(Si3.68Al0.32)Σ4O10 (F1.40(OH)0.60)Σ2. The idealized formula is as follows: Rb(LiAl1.5□0.5)[Al0.5Si3.5O10]F2. Voloshinite forms a continuous solid solution with lepidolite. According to X-ray single crystal study, voloshinite is monoclinic, space group C2/ c. The unit-cell dimensions are: a = 5.191, b = 9.025, c = 20.40 Å, β = 95.37°, V= 951.5 Å3, Z = 4. Polytype is 2 M 1. The strongest reflections in the X-ray powder diffraction pattern ( d, Å- I[ hkl]) are: 10.1-60[001]; 4.55-80[020, 110, 11 bar 1 ]; 3.49-50[11 bar 4 ]; 3.35-60[024, 006]; 3.02-45[025]; 2.575-100[11 bar 6 , 131, 20 bar 2 , 13