Preparation, characterization and uses of mullite grain

Al-Jarsha, Y. M. M.; Emblem, H. G.; Jones, Kenneth A.; Rahman, M. A.; Davies, T. J.; Wakefield, R.; Sargeant, G. K.

doi:10.1007/bf00584897

Cited by 10 publications

(4 citation statements)

References 7 publications

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“…Mullite is an important material for high volume applications because of its good mechanical and electrical (insulation) properties achieved through using low cost and abundant (alumina, silica, and kaolinitic clays) raw materials. Mullite can be produced in large quantities either as solid solution of alumina‐silica mixture or by transformation of kaolinitic clays . Mullite produced from kaolinite is the main interest of this paper so the other production routes will not be addressed.…”

Section: Introductionmentioning

confidence: 99%

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Impact of spark plasma sintering (SPS) on mullite formation in porcelains

et al. 2017

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The effect of the spark plasma sintering (SPS) process on mullite formation in porcelains was studied using X‐ray diffraction, scanning electron microscopy, and transmission electron microscopy. SPS affected the kinetics and morphology of formed mullite. After sintering at 1100°C, unlike conventional sintering, SPS promoted the formation of mullite due to the combination of vacuum and applied pressure. Mullite crystal growth was altered by the atmosphere (vacuum), dwell time (0‐15 minutes), and temperature (1000‐1200°C). The applied pressure caused the mullite needles to orient perpendicular to the direction of the applied load. Depending on SPS dwell time, the mullite formed after sintering at 1100°C also had different crystal structure (tetragonal for short dwell time of 0‐5 minutes and orthorhombic for a long dwell time of 10‐15 minutes). Dissolution of mullite was observed at 1100°C by extending the dwell time by up to 15 minutes and the dissolved mullite reprecipitated on the small needles (~40 nm) and coarsened via Oswald ripening resulting in larger mullite needles (~60 nm).

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Section: Introductionmentioning

confidence: 99%

“…Mullite can be produced in large quantities either as solid solution of alumina-silica mixture or by transformation of kaolinitic clays. [16][17][18][19][20][21] Mullite produced from kaolinite is the main interest of this paper so the other production routes will not be addressed.…”

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confidence: 99%

Impact of spark plasma sintering (SPS) on mullite formation in porcelains

et al. 2017

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“…The transformation of kaolinite has been widely reported; it partly decomposed at ca. 600 °C and completely transformed to an X‐ray amorphous phase after heating up to 815 °C, as shown in Fig.…”

Section: Resultsmentioning

confidence: 99%

Analysis of the transformation behaviors of a Chinese coal ash using in‐/ex‐situ XRD and SEM‐EXD

Lin

Wang

Miyawaki

et al. 2014

Asia-Pacific J Chem Eng

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Crystal and phase transitions of a Chinese Datong coal ash were evaluated using room temperature X-ray diffraction (RT-XRD), in-situ high temperature (HT)-XRD, and scanning electron microscope combining energy dispersive X-ray analysis (SEM-EDX) as temperature varied from 300°C to 1600°C. The transforming behaviors of ash were related to its melting properties. Results revealed that the transforming behavior of minerals from in-situ HT-XRD was different with that from routine RT-XRD. Low-temperature Datong ash contained quartz and clays (such as kaolinite); the changes in minerals at low-temperature region (300-1000°C) were mainly due to the minerals decomposition and partial phase transition. Significant transition of quartz to cristobalite occurred at ca. 1100°C; the continuous transition and reaction of silica and alumina at ca. 1200°C accelerated the softening of the ash (ST ≈ 1290°C). An X-ray amorphous liquid phase was formed mainly by the eutectic solution of silica and mullite at ca. 1400°C, which obviously affected the hemisphere temperature (HT ≈ 1490°C) of ash; meanwhile, ultra fine alumina solid particles, which were probably derived from kaolinite, were found in the melted ash. Virtually, the fusing (FT > 1500°C) of Datong ash was considered to be determined by the formation of solid particles and eutectic solution. Eventually, the semi-quantitative evaluation of transformations of ash was successfully obtained through the combined methods.

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“…Its high refractoriness, density, chemical resistance, and mechanical strength have made it a very much attractive material in ceramics. [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] The present prepared materials can provide mechanical, chemical, and thermally resistant potential constructions for brick-lining of furnaces, boilers, crucibles, high temperature furnace casted tubes and casted furnace chambers for industries and engineerings. 21 Fly ash contains some amorphous silica, alumina and a small percentage of different metal oxides and crystalline components such as a small amount of mullite and quartz.…”

Section: Introductionmentioning

confidence: 99%

Novel Utilization of Bauxite‐Treated Fly Ash‐Based Ceramics for its Antibacterial Activity

Parveen

Das

Bhattacharya

et al. 2012

Int J Applied Ceramic Tech

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Nowadays the increased generation of fly ash from thermal power plants is a major concern to our society due to its harmful impact on environment. To utilize this waste in a useful way, we have developed a novel ceramic material which was produced by treating fly ash with bauxite during sintering process. The developed ceramic material acquired increased hardness because of enhanced mullite content during the process with an additional property of reducing pathogenic bacterial growth by more than 90%. The mechanism of their antibacterial action was studied by TEM image analysis of the bacterial cross section. Mullite content and the crystallinity of mullite have increased with increasing concentration of bauxite during sintering process. A maximum of ~ 31% increase in mullite phase was obtained for 50% w/w bauxite and thus increased the hardness which was measured by LEICA Vickers hardness tester. The structural composition of the developed ceramics materials and the surface texture were evaluated by FTIR studies and FESEM micrographs, respectively. This work highlights a sustainable approach of using fly ash in developing antimicrobial ceramics in an eco‐friendly way having a vast potential to be used in the bacteria prone area like hospitals.

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Preparation, characterization and uses of mullite grain

Cited by 10 publications

References 7 publications

Impact of spark plasma sintering (SPS) on mullite formation in porcelains

Impact of spark plasma sintering (SPS) on mullite formation in porcelains

Analysis of the transformation behaviors of a Chinese coal ash using in‐/ex‐situ XRD and SEM‐EXD

Novel Utilization of Bauxite‐Treated Fly Ash‐Based Ceramics for its Antibacterial Activity

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