Evaluation of rare earth on layered silicates under subcritical conditions: Effect of the framework and interlayer space composition

Chain, Pablo; Cota, Agustín; Mrabet, Said El; Pavón, Esperanza; Pazos, Manuel; Alba, María D.

doi:10.1016/j.chemgeo.2013.03.006

Cited by 6 publications

(1 citation statement)

References 47 publications

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“…The influence of the humidity aging on the delay powder can also be examined using X-ray diffraction in order to detect the emergence of any new crystalline phase or whether there is a change in the lattice parameters or the crystal structure of the minerals that composes the delay powder. Based on the comparison between the XRD patterns (Figure 6a) of the fresh powder and the one aged for 100 days under moisture, it is possible to notice the appearance of low-intensity diffraction peaks at 2θ = {23.2°} and 2θ = {20.1°, 39.3°, 69.8°} which could indicate the presence of hydrated silicate H 2 Si 2 O 5 [63] and silicon dioxide SiO 2 , respectively, as by-products of moisture aging.…”

Section: Xrd and Sem Analysesmentioning

confidence: 99%

Towards a Deep Insight Into Thermal and Moisture Aging of Silicon‐Based Pyrotechnic Delay Composition Through a Combination of Spectroscopic Techniques – Principal Component Analysis Approaches

Abdelaziz

Bekhouche

Tarchoun

et al. 2022

Propellants Explo Pyrotec

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The aging of pyrotechnics is heavily influenced by temperature and humidity during their long-term storage. The investigation of the aging mechanisms of such composites is of great interest for their safe storage and use in weapon systems, hence avoiding any unexpected phenomenon or decrease in performance. This study is aimed at understanding the aging effects related to temperature and moisture on pyrotechnic delays composed of silicon as fuel and lead oxide (Pb 3 O 4 ) and barium chromate (BaCrO 4 ) as oxidizers. The aged samples were considered for spectroscopic analysis using Fourier transformed infrared spectroscopy (FTIR), Raman spectroscopy, X-ray diffraction spectroscopy (XRD), and surface morphology analysis using scanning electron microscopy (SEM). The results obtained showed that temperature and moisture induce distinct structural and morphological modifications on the composition. The thermal aging causes thermal decomposition of the lead oxide, followed by the oxidation of the fuel particles to form silicon dioxide (SiO 2 ). On the other hand, under moisture, the lead oxide is stable and does not participate in the aging process and the barium chromate is converted to chromium oxide molecules Cr 2 O 3 . At the same time, Si is oxidized to SiO 2 and orthosilicic acid Si(OH) 4 in the presence of humidity. The SEM images revealed that the surface of the aged samples tended to be rough in addition to the formation of surface cracks. At low aging periods of 20, 40, and 60 days, no chemical alterations have been noticed, whereas, beyond 80 days, the changes become more apparent. By coupling the above analytical techniques with principal component analysis (PCA), it was possible to accurately differentiate the aged samples according to their aging time and to detect any compositional change within the powder even at low aging periods.

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Section: Xrd and Sem Analysesmentioning

confidence: 99%

Towards a Deep Insight Into Thermal and Moisture Aging of Silicon‐Based Pyrotechnic Delay Composition Through a Combination of Spectroscopic Techniques – Principal Component Analysis Approaches

Abdelaziz

Bekhouche

Tarchoun

et al. 2022

Propellants Explo Pyrotec

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Influence of temperature and time on the Eu 3+ reaction with synthetic Na-Mica- n ( n = 2 and 4)

García-Jiménez

Cota²,

Osuna

et al. 2016

Chemical Engineering Journal

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Impact of hydrothermal treatment of FEBEX and MX80 bentonites in water, HNO3 and Lu(NO3)3 media: Implications for radioactive waste control

Osuna

Chain

Cota

et al. 2015

Applied Clay Science

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15 Engineered barriers of deep geological repositories (DGR) are commonly 16 constructed with bentonite. FEBEX and MX80 bentonites have been selected by different 17 countries as reference materials for the sealing of repositories; however, their chemical 18 reactivity with high-level long-lived radioactive wastes (HLRW) under subcritical 19 conditions had not been explored before. The hydrothermal stability in neutral and acid 20 media and chemical reactivity in contact with an actinide analogous compound were both 21 studied. The long-range and short-range structural changes were analyzed by X-ray 22 diffraction, nuclear magnetic resonance and scanning electron microscopy. Both bentonites 23 have exhibited a good stability in neutral and acid media and have generated a new phase 24 immobilizing the actinide analogous compound. The extent of the chemical reaction is 25 higher in MX80 bentonite than in FEBEX bentonite.26 27

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Evaluation of rare earth on layered silicates under subcritical conditions: Effect of the framework and interlayer space composition

Abstract: 14Clay-based minerals are considered to be an important component in backfill 15 barriers due to both their ability to seal and adsorb radioactive waste and to interact 16 chemically with it under subcritical conditions. Herein, we describe a systematic study of

Cited by 6 publications

References 47 publications

Towards a Deep Insight Into Thermal and Moisture Aging of Silicon‐Based Pyrotechnic Delay Composition Through a Combination of Spectroscopic Techniques – Principal Component Analysis Approaches

Towards a Deep Insight Into Thermal and Moisture Aging of Silicon‐Based Pyrotechnic Delay Composition Through a Combination of Spectroscopic Techniques – Principal Component Analysis Approaches

Influence of temperature and time on the Eu 3+ reaction with synthetic Na-Mica- n ( n = 2 and 4)

Impact of hydrothermal treatment of FEBEX and MX80 bentonites in water, HNO3 and Lu(NO3)3 media: Implications for radioactive waste control

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