Tobermorite formation in the system CaO, C3SSiO2Al2O3NaOHH2O under hydrothermal conditions

Gabrovšek, Roman; Kurbus, B.; Mueller, D.; Wieker, W.

doi:10.1016/0008-8846(93)90097-s

Cited by 42 publications

(29 citation statements)

References 7 publications

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“…By comparing the CLQ values of 0.27, 0.25 and 0.13 for Al/(Al + Si) ¼ 0.01, 0.03, and 0.12 to the maximum theoretical CLQ value of 0.33, it can be seen that approximately 81.8%, 75.7% and 39.4% of all of the bridging tetrahedra were 29 Si NMR (left groups) and 27 Al NMR (right groups) spectra of the products prepared at 180 C for 7 h with different aluminum additions. [6], which is based on previous studies in which the resonance of Al [6] that was at 10-12 ppm when reported by Gabrovŝek et al 48 also occurred at 0-10 ppm when researched by Coleman and Komarneni et al 4,38 It is clear that the intensity and amplitude of the resonances due to Al [4] became weaker and broader with an increasing Al/ (Al + Si) ratio, suggesting a decreasing content and disordered structure. Conversely, the intensity of Al [6] increased with a rising Al/(Al + Si) ratio.…”

Section: 14mentioning

confidence: 70%

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Microstructure and characterization of aluminum-incorporated calcium silicate hydrates (C–S–H) under hydrothermal conditions

Zhao

2018

RSC Adv.

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The phase assembly and microstructure of the aluminum-incorporated CaO-SiO 2 -H 2 O system, which is technologically important in autoclaved building materials, catalysis and waste management, were investigated using XRD, SEM, FTIR and NMR depending on aluminum addition, reaction temperature and curing time. The content of each phase was obtained using the MAUD program based on the Rietveld refinement. The results revealed that the formation of the tobermorite phase was promoted at Al/(Al + Si) # 0.03, and subsequently retarded by higher aluminum addition, which was corroborated by the presence of more low polymerized and cross-linked (alumino)silicate chains. The phase purity decreased with increasing aluminum addition. Aluminum changed the morphology of tobermorite from plate-like to lath-like and fibrous. About a quarter of the (alumino)silicate chains in the C-S-H structure were linked though a^Si-O-Al^configuration, and this proportion was almost independent of aluminum addition. Furthermore, only Al[4] substituted for silicon in the aluminum incorporated C-S-H, while Al [6] just exited in the hydrogarnet phase. This work is beneficial for understanding the implication on microproperties of by-products or admixtures containing aluminum in concrete.

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Section: 14mentioning

confidence: 70%

“…Meanwhile, Gabrovŝek et al 48 assigned the signals at À86 and À82.5 ppm to the Q 2 and Q 2 (1Al) sites, and those at À96 and À92 ppm to the Q 3 and Q 3 (1Al) sites. Thus, the resonances at À88.51 ppm, À89.13 ppm and À88.42 ppm in this study were …”

mentioning

confidence: 99%

Microstructure and characterization of aluminum-incorporated calcium silicate hydrates (C–S–H) under hydrothermal conditions

Zhao

2018

RSC Adv.

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“…We have measured two signals for Q 3 sites (Figure 4b) at −98.5 ppm and −93.9 ppm, respectively, in the spectra of T-A sample. The signals at −88.2 ppm, −86.3 ppm and −84.9 ppm can be assigned to Q 2 sites according the results of Gabrovŝek et al [30], in which Q 2 sites for Al-substituted tobermorite located at −85 to −89 ppm. Our Q 3 (1Al) and Q 2 (1Al) sites are located at −91.0 ppm and −82.6 ppm, respectively.…”

Section: Resultsmentioning

confidence: 88%

“…By comparison, Coleman [11] identified that Q 2 and Q 2 (1Al) sites located at −86.5 and −83.5 ppm, while Q 3 and Q 3 (1Al) sites corresponded with signals at −98.4 and −93.5 ppm, respectively. Gabrovŝek et al [30] assigned signals at −86 and −82.5 ppm to Q 2 and Q 2 (1Al) sites, those at −96 and −92 ppm were attributed to Q 3 and Q 3 (1Al) sites. We have measured two signals for Q 3 sites (Figure 4b) at −98.5 ppm and −93.9 ppm, respectively, in the spectra of T-A sample.…”

Section: Resultsmentioning

confidence: 99%

Synthesis, Characterization and Hexavalent Chromium Adsorption Characteristics of Aluminum- and Sucrose-Incorporated Tobermorite

Zhao

Wei

et al. 2017

Materials

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Tobermorites were synthesized from the lime-quartz slurries with incorporations of aluminum and sucrose under hydrothermal conditions, and then used for adsorption of Cr(VI). The chemical components, and structural and morphological properties of tobermorite were characterized by X-ray diffraction (XRD), thermogravimetric-differential scanning calorimetry (TG-DSC), Fourier transform infrared spectroscopy (FT-IR), nuclear magnetic resonance (NMR), scanning electron microscopy (SEM), X-ray photoelectron spectroscopic (XPS) and N2 adsorption–desorption measurements. The formation and crystallinity of tobermorite could be largely enhanced by adding 2.3 wt.% aluminum hydroxide or 13.3 wt.% sucrose. Sucrose also played a significantly positive role in increasing the surface area. The adsorption performances for Cr(VI) were tested using a batch method taking into account the effects of pH, the adsorption kinetics, and the adsorption isotherms. The adsorption capacities of the aluminum- and sucrose-incorporated tobermorites reached up to 31.65 mg/g and 28.92 mg/g, respectively. Thus, the synthesized tobermorites showed good adsorption properties for removal of Cr(VI), making this material a promising candidate for efficient bulk wastewater treatment.

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“…An additional sample was synthesised at 220°C for 2 weeks. Hydrothermal treatment either at lower temperatures or for shorter than 1 week were investigated, but these were found to yield 11 Å tobermorite over xonotlite, which is known to be metastable under such conditions [4], indeed in many other studies into the formation and stability of xonotlite, tobermorite-xonotlite mixtures have been the early stage or low temperature reaction products [2][3][4][5]. After hydrothermal treatment, the samples were washed with ethanol and dried at 60°C in a drying cabinet.…”

Section: Synthetic Xonotlitementioning

confidence: 99%

Structure, bonding and morphology of hydrothermally synthesised xonotlite

Black¹,

Garbev²,

Stumm³

2008

Advances in Applied Ceramics

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We have systematically investigated the role of synthesis conditions upon the structure and morphology of xonotlite. Starting with a mechanochemically-prepared, semi-crystalline phase with Ca:Si = 1, we have prepared a series of xonotlite samples hydrothermally, at temperatures between 200 and 250°C. Analysis in each case was by x-ray photoelectron spectroscopy (XPS), environmental scanning electron microscopy (ESEM) and x-ray diffraction (XRD). There was increased silicate polymerisation with both increased synthesis temperature and duration of synthesis. Concerning crystal morphology, there was an increase in crystal size with increasing temperature, but this led to some crystal damage. Longer hydrothermal treatment however led to more perfect crystal morphologies.

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Tobermorite formation in the system CaO, C3SSiO2Al2O3NaOHH2O under hydrothermal conditions

Cited by 42 publications

References 7 publications

Microstructure and characterization of aluminum-incorporated calcium silicate hydrates (C–S–H) under hydrothermal conditions

Microstructure and characterization of aluminum-incorporated calcium silicate hydrates (C–S–H) under hydrothermal conditions

Synthesis, Characterization and Hexavalent Chromium Adsorption Characteristics of Aluminum- and Sucrose-Incorporated Tobermorite

Structure, bonding and morphology of hydrothermally synthesised xonotlite

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