29Si and 27Al MAS NMR Characterization of the Structural Evolution of a Lateritic Clay under Acidic and Alkaline Treatments
| Autor: | Benoît Nait-Ali, Léon Koffi Konan, Hervé Goure-Doubi, Agnès Smith, Gisèle Laure Lecomte-Nana, Valérie Montouillout |
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| Přispěvatelé: | Groupe d'Etudes des Matériaux Hétérogènes (GEMH), Université de Limoges (UNILIM)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM), Conditions Extrêmes et Matériaux : Haute Température et Irradiation (CEMHTI), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université d'Orléans (UO) |
| Rok vydání: | 2018 |
| Předmět: |
inorganic chemicals
Goethite Population 020101 civil engineering 02 engineering and technology engineering.material complex mixtures 01 natural sciences 0201 civil engineering Kaolinite education Dissolution ComputingMilieux_MISCELLANEOUS Lime education.field_of_study Chemistry [CHIM.MATE]Chemical Sciences/Material chemistry Hematite 010406 physical chemistry 0104 chemical sciences NMR spectra database Solid-state nuclear magnetic resonance 13. Climate action visual_art visual_art.visual_art_medium engineering Nuclear chemistry |
| Zdroj: | Journal of Material Science & Engineering Journal of Material Science & Engineering, 2018, 07 (01), ⟨10.4172/2169-0022.1000409⟩ |
| ISSN: | 2169-0022 |
| DOI: | 10.4172/2169-0022.1000409 |
| Popis: | In the present work the modifications induced by the geomimetic processing on the environment of silicon and aluminum atoms are finely characterized by solid state MAS NMR. The raw clay (Lat), a lateritic clay from Yaounde (Cameroon), contains kaolinite, quartz, hematite and goethite as major mineral phases. This material is treated under acidic conditions during 24 h (LatAF) and then under alkaline conditions during 18 days, leading to the final consolidated “geomimetic” product (LatAFCH). The samples have been characterized by 29Si and 27Al solid state NMR at each step of the process.The NMR spectra obtained for the starting clay indicate the presence of AlIV and AlVI populations together with silicon Q2 (0 or 1Al) and Q3 (0 or 1Al) environments located at δiso=-83 ppm and δiso=-91 ppm respectively.The acidic reaction during 24 h, does not significantly affect the silicon-rich layers. It induces a conversion of part of AlIV population into AlVI environment mainly related to the occurrence of six-fold organo-aluminum complexes when using fulvic acid. With inorganic acid, Al dissolution prevails.The neutralization (using lime) of the medium, followed by ageing for 18 days, promotes clay interactions with available calcium ions. The newly formed phases are cementitious CSH, CASH and CAH phases. |
| Databáze: | OpenAIRE |
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