Structural changes of SiO2 glass by mechanical milling

Iwao, Masaru; Okuno, Masayuki; Koyano, Mikio; Katayama, Shin–ichi

doi:10.2465/jmps.090810

Cited by 10 publications

(8 citation statements)

References 14 publications

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“…Generally, particles with extremely high surface energy tend to agglomerate to reduce their surface energy. For example, similar agglomeration was also reported in milling experiments of antigorite and fused silica (Bishop et al, 2008;Iwao et al, 2010). On the other hand, the specific area of the milled sample became almost constant after 150 h of milling; our results also showed an initial decrease followed by a prominent increase in apparent particle size by agglomeration after 600 h of milling.…”

Section: Variation Of Particle Size and Surface Area With Millingsupporting

confidence: 73%

“…13) was similar to that for the crystallinity with milling time, suggesting that the luminescence originated from defects, such as dislocations in small particles formed by milling (Leoni et al, 2004), in addition to dangling bonds at grain surfaces (Pizani et al, 2008). This type of high luminescence was also observed in ground SiO 2 glass (Pizani et al, 2008;Iwao et al, 2010).…”

Section: Structural Change and Amorphization By Millingsupporting

confidence: 58%

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Structural change of alkali feldspar by ball milling

Nojiri

Okuno

Okudera

et al. 2013

Journal of Mineralogical and Petrological Sciences

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The structural changes and amorphization of alkali feldspar by ball milling were investigated using X -ray diffraction (XRD), Fourier -transform infrared (FTIR) spectroscopy, Raman spectroscopy, scanning electron microscopy (SEM), thermal analysis, particle size analysis, and specific surface area measurements. The Or 77 Ab 23 alkali feldspar crystal has an Ab -rich lamella texture in Or -rich host crystals. The mean particle size decreased from ~ 67 μm to almost 3 μm after 50 h of ball milling. After 600 h of ball milling, the apparent mean particle size calculated from the observed particle size distribution increased prominently because of the agglomeration of small particles. It reached ~ 38 μm after 1200 h of ball milling. While the density variation was not consistent with that of the particle size, it was consistent with that of the crystallinity estimated from X -ray diffraction data. The FTIR and Raman spectra indicated breaking of the Si -O -Si or Al -O -Si bonds and the formation of defects and distortion of the TO 4 (T = Si or Al) tetrahedra as a result of the milling. An increase in the intensity of luminescence with milling supported these results. XRD analysis revealed the sample that was ball milled for 1200 -h was amorphous. However, the structure and properties of this amorphous phase were different from those of fused feldspar glass and had weak crystalline features. These amorphous materials were similar to those in the fault zone that were formed naturally and experimentally without melting. The Si -OH (or Al -OH) shoulders ν = 890 cm −1 ) in the FTIR spectra were formed by the chemical reaction between the broken Si -O -Si (or Al -O -Si) bonds and atmospheric water surrounding the 300 -h milled samples. Because of this reaction, the surface and interior structure of the milled particles depended on the agglomeration and formation of defects formation resulting from the long milling time. XRD results of the milled samples indicated that grains with a larger amount of Ab -rich lamella structures were downsized more rapidly than the Or -rich host.

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Section: Variation Of Particle Size and Surface Area With Millingsupporting

confidence: 73%

Section: Structural Change and Amorphization By Millingsupporting

confidence: 58%

Structural change of alkali feldspar by ball milling

Nojiri

Okuno

Okudera

et al. 2013

Journal of Mineralogical and Petrological Sciences

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“…An increase in the amount of calcium ions released from C-S-H gel is expected to result in a collapse of this structure. The planetary ball milling of silica glass induces structural changes, including a breakdown of the Si–O bonds, leading to a decrease in the degree of distortion of the SiO 4 tetrahedra [14]. We speculate that such a milling process would induce changes in the structure of C-S-H gel as well.…”

Section: Introductionmentioning

confidence: 99%

Structural changes in calcium silicate hydrate gel and resulting improvement in phosphate species removal properties after mechanochemical treatment

2018

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The discharge of phosphate species into aqueous environments is a key issue for eutrophication prevention. In this study, we investigate a mechanochemical treatment of calcium silicate hydrate (C-S-H) gel with different organic solvents with the aim of changing its structure and improving its phosphate species removal properties. The treatment leads to a collapse of the gel structure, resulting in the formation of defective structures in the silicate anion chains. The C-S-H gel sample milled with acetone exhibits better phosphate species recovery characteristics than does the unmilled C-S-H gel sample or the C-S-H gel sample milled with 1-propanol. Ultraviolet irradiation during phosphate recovery using the C-S-H gel sample milled with acetone further enhances the recovery properties.

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“…3 µm without pretreatment. Silica gel (Wako Pure Chemical Industries, Ltd) and commercially available fused silica glass (Iwao et al, 2010) were ground with a mortar and used as reference materials. These particle size ranged from a max.…”

Section: Sample Preparationmentioning

confidence: 99%

SiO<sub>4</sub> network structure changes and crystallization of diatom shells in diatomaceous earth by heat treatment

Sasaki

Arasuna

Okuno

2021

Journal of Mineralogical and Petrological Sciences

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Diatomaceous earth (DE) samples from the Nevada, United States of America and the Noto region, Ishikawa Prefecture, Japan were subjected to heat treatment of up to 1200°C, and their SiO 4 network structurer changes and crystallization were characterized in detail by thermogravimetric and X-ray diffraction analyses, and infrared and Raman spectroscopies. Raman spectra for the Nevada-DE revealed that the SiO 4 network structure of the unheated diatom shells in Nevada-DE may be mainly composed of 6-membered rings of SiO 4 tetrahedra. In addition, with heat treatment above 600°C, this rings structure increased and 4-and 3-membered rings of SiO 4 tetrahedra appeared, whereby the SiO 4 network structure became similar to that of silica glass. The first diffraction peak (FSDP) position of X-ray diffraction patterns showed the size of the medium-range structure of diatom shells in Nevada-DE and Noto-DE may be smaller than that of silica glass but larger than that of silica gel. Since the FSDP position of Nevada-DE and Noto-DE is the same, the medium-range structure of Noto-DE may also compose of the 6-membered rings of SiO 4 tetrahedra. Furthermore, the crystallization temperature (1100°C) from biogenic amorphous silica such as diatom shells in Nevada-DE and Noto-DE to cristobalite was lower than that (1200°C) of inorganic amorphous silica such as silica gel. Raman spectra show that the SiO 4 network structure in diatom shells for unheated Nevada-DE is mainly composed the 6-membered rings of SiO 4 tetrahedra such as cristobalite, and the 6-membered rings in SiO 4 network structure is increased at a lower temperature than silica gel. It suggested that the diatom shells in Nevada-DE easily crystallize to cristobalite at a lower temperature than silica gel.

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Structural changes of SiO2 glass by mechanical milling

Cited by 10 publications

References 14 publications

Structural change of alkali feldspar by ball milling

Structural change of alkali feldspar by ball milling

Structural changes in calcium silicate hydrate gel and resulting improvement in phosphate species removal properties after mechanochemical treatment

SiO<sub>4</sub> network structure changes and crystallization of diatom shells in diatomaceous earth by heat treatment

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