EM - Escola de Minas

URI permanente desta comunidadehttp://www.hml.repositorio.ufop.br/handle/123456789/6

Notícias

A Escola de Minas de Ouro Preto foi fundada pelo cientista Claude Henri Gorceix e inaugurada em 12 de outubro de 1876.

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Filtros

20154

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Autor: search.filters.author.Romano, Antônio WilsonAssunto: search.filters.subject.Silicate

Resultados da Pesquisa

Agora exibindo 1 - 4 de 4
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    A vibrational spectroscopic study of the silicate mineral harmotome – (Ba,Na,K)1-2(Si,Al)8O16 6H2O – a natural zeolite.
    (2015) Frost, Ray Leslie; López, Andrés; Wang, Lina; Romano, Antônio Wilson; Cipriano, Ricardo Augusto Scholz
    The mineral harmotome (Ba,Na,K)1-2(Si,Al)8O16 6H2O is a crystalline sodium calcium silicate which has the potential to be used in plaster boards and other industrial applications. It is a natural zeolite with catalytic potential. Raman bands at 1020 and 1102 cm 1 are assigned to the SiO stretching vibrations of three dimensional siloxane units. Raman bands at 428, 470 and 491 cm 1 are assigned to OSiO bending modes. The broad Raman bands at around 699, 728, 768 cm 1 are attributed to water librational modes. Intense Raman bands in the 3100 to 3800 cm 1 spectral range are assigned to OH stretching vibrations of water in harmotome. Infrared spectra are in harmony with the Raman spectra. A sharp infrared band at 3731 cm 1 is assigned to the OH stretching vibration of SiOH units. Raman spectroscopy with complimentary infrared spectroscopy enables the characterization of the silicate mineral harmotome.
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    SEM, EDX, Infrared and Raman spectroscopic characterization of the silicate mineral yuksporite.
    (2015) Frost, Ray Leslie; López, Andrés; Cipriano, Ricardo Augusto Scholz; Theiss, Frederick L.; Romano, Antônio Wilson
    The mineral yuksporite (K,Ba)NaCa2(Si,Ti)4O11(F,OH) H2O has been studied using the combination of SEM with EDX and vibrational spectroscopic techniques of Raman and infrared spectroscopy. Scanning electron microscopy shows a single pure phase with cleavage fragment up to 1.0 mm. Chemical analysis gave Si, Al, K, Na and Ti as the as major elements with small amounts of Mn, Ca, Fe and REE. Raman bands are observed at 808, 871, 930, 954, 980 and 1087 cm 1 and are typical bands for a natural zeolite. Intense Raman bands are observed at 514, 643 and 668 cm 1. A very sharp band is observed at 3668 cm 1 and is attributed to the OH stretching vibration of OH units associated with Si and Ti. Raman bands resolved at 3298, 3460, 3562 and 3628 cm 1 are assigned to water stretching vibrations.
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    A vibrational spectroscopic study of the silicate mineral normandite – NaCa(Mn2+,Fe2+)(Ti,Nb,Zr)Si2O7(O,F)2.
    (2015) Frost, Ray Leslie; López, Andrés; Theiss, Frederick L.; Cipriano, Ricardo Augusto Scholz; Romano, Antônio Wilson
    We have studied the mineral normandite using a combination of scanning electron microscopy with energy dispersive spectroscopy and vibrational spectroscopy. The mineral normandite NaCa(Mn2+,Fe2+)(Ti,Nb,Zr)Si2O7(O,F)2 is a crystalline sodium calcium silicate which contains rare earth elements. Chemical analysis shows the mineral contains a range of elements including Na, Mn2+, Ca, Fe2+ and the rare earth element niobium. No Raman bands are observed above 1100 cm 1. The mineral is characterised by Raman bands observed at 724, 748, 782 and 813 cm 1. Infrared bands are broad; nevertheless bands may be resolved at 723, 860, 910, 958, 933, 1057 and 1073 cm 1. Intense Raman bands at 454, 477 and 513 cm 1 are attributed to OSiO bending modes. No Raman bands are observed in the hydroxyl stretching region, but low intensity infrared bands are observed at 3191 and 3450 cm 1. This observation brings into question the true formula of the mineral.
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    A vibrational spectroscopic study of the silicate mineral pectolite – NaCa2Si3O8(OH).
    (2015) Frost, Ray Leslie; López, Andrés; Theiss, Frederick L.; Romano, Antônio Wilson; Cipriano, Ricardo Augusto Scholz
    The mineral pectolite NaCa2Si3O8(OH) is a crystalline sodium calcium silicate which has the potential to be used in plaster boards and in other industrial applications. Raman bands at 974 and 1026 cm 1 are assigned to the SiO stretching vibrations of linked units of Si3O8 units. Raman bands at 974 and 998 cm 1 serve to identify Si3O8 units. The broad Raman band at around 936 cm 1 is attributed to hydroxyl deformation modes. Intense Raman band at 653 cm 1 is assigned to OSiO bending vibration. Intense Raman bands in the 2700–3000 cm 1 spectral range are assigned to OH stretching vibrations of the OH units in pectolite. Infrared spectra are in harmony with the Raman spectra. Raman spectroscopy with complimentary infrared spectroscopy enables the characterisation of the silicate mineral pectolite.