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Browsing ELibrary by Title
Now showing items 11509-11528 of 21934
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(2005)This paper reports the results of hydrothermal synthesis in the system Na2O-MgO-FeO-Fe2O3-SiO2-H2O. Four samples of stoichiometric magnesioriebeckite composition, ideally □Na2Mg3Fe3+2 Si8O22(OH)2, were run at 700–800 °C, ...
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(1990)The present work, we synthesized germanium-containing quartz crystals from 0.5N NaOH solutions by the thermal gradient method, at crystallization temperatures from 270° to 670°C and a pressure of 1.6 kbar. The experiments ...
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(1990)One of the unsolved problems of experimental mineralogy is the synthesis of single crystals of anadalusite. Because of the geochemical similarity of aluminum to gallium, and of silicon to germanium. This permits the use ...
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(2001)Weathered and sedimentary rocks (bauxites, clays, etc.) are promising but poorly investigated and rarely used sources of REE. These rocks are characterized by very low contents of rare-metal minerals in contrast to relatively ...
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(2004)Beryllium is a significant constituent in sapphirine in some metamorphic and pegmatitic rocks, and thus could have a major effect on its stability relationships. Using the stoichiometries of reactions involving sapphirine ...
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(2002)Beryllian sapphirine Mg4−xAl4+x[Al4+x−2yBeySi2−x+yO18]O2 has been synthesized from starting compositions with y ≤ 1 at x = 0 and y ≤ 0.5 at x = 0.5, P = 0.1–1.3 GPa, T = 700–1350 °C. Electron diffraction shows the sapphirines ...
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(2004)An O2 oxidation and freeze-dry procedure has been used to synthesize birnessite through the oxidation of Mn2+ in alkali media. The effects of O2 flow rate, the fluxion velocity of reaction suspension, the reaction temperature, ...
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(2000)Ca-tourmaline has been synthesized hydrothermally in the presence of Ca(OH)2 and CaCl2-bearing solutions of different concentration at T = 300-700 °C at a constant fluid pressure of 200 MPa in the system CaO-MgO-Al2O3-Si ...
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(2001)At 700°C and 500 MPa fullerite multilayer formations with diameters from 200 to 800 Å were synthesized from polypropylen. The diameter of the inner cavity or channel in these structures varied from 20 to 60 Å. These ...
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(2002)mm-sized crystals of enstatite were synthesized under H2O-saturated conditions at 25 kbar in a piston-cylinder apparatus. The bulk starting composition corresponded to enstatite, silica and water in the respective proportions ...
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(2001)We have produced synthetic feldspar bicrystals using a direct bonding technique. A gem-quality orthoclase crystal from Itrongay, Madagascar, was used for the bonding experiments. Microprobe analysis shows only minor ...
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(2004)Layered double hydroxides (LDHs) are known as ‘anionic clays’. They comprise a class of material with positively charged octahedral double hydroxyl layers and exchangeable anions. The Li/Al LDH term includes a group of ...
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(2004)Omphacites with varying Na/K ratio were synthesized in the system CaMgSi2O6-NaAlSi2O6-KAlSi 2O6 at pressures of 5, 6, and 7 GPa within the temperature interval 1000-1300°C. It was found that both K and Na contents of ...
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(1996)A number of experiments have been carried out using Cl-, Na-, K-, As-, Sn-, Bi-, Pb-, Te-bearing solutions at temperatures between 240 and 500°C in order to synthesize platinum-group minerals (PGM) and to study their ...
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(1995)The synthesis of polycyclic aromatic hydrocarbons (PAHs) from benzene by shock waves was studied in order to search for a novel possibility of PAH formation under cosmochemical conditions. Shock waves generated by projectile ...
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(1996)Some recent investigations of black shales reveal platinum-group element (PGE) concentrations in the ppm range. The low temperature nature of these mineralized sediments and their composition stimulated this first attempt ...
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(2003)In order to evaluate the stability of Mg-Ca garnets at P = 2.5 GPa/T = 800-1500 °C, some experiments were performed using both natural and synthetic starting materials. Particular attention was paid to the investigation ...
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(2004)Diamond was synthesized at high temperature and pressure in a Walker-style multianvil apparatus from various supercritical C-O-H rich fluid compositional systems. Depending on the type and amount of impurities added to the ...
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(2003)We document experiments on a natural metapelite in the range 650–775°C, 6–14 kbar, 10 wt?% of added water, and 700–850°C, 4–10 kbar, no added water. Staurolite systematically formed in the fluid-present melting experiments ...
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(1999)Thallium leucite, TlAlSi2O6, has been synthesized at 450°C for 7 days, under ambient conditions, by the transformation of dehydrated analcime NaAlSi2O6 in the presence of excess TlCl. This substitution of Tl for Na leads ...
Now showing items 11509-11528 of 21934