Contribution to porous mullite synthesis from clays by adding Al and Mg powders

Esharghawi, A.; Penot, C.; Nardou, Françoise

doi:10.1016/j.jeurceramsoc.2008.05.036

Cited by 55 publications

(41 citation statements)

References 26 publications

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“…Similar results of the thermal behavior for kaolin and aluminum were presented also by A. Esharghawi [4][5]. Test sample 4 showed only one endothermic peak at 393 ºC relating to Mg(OH)2 dehydration.…”

Section: Resultssupporting

confidence: 84%

“…However, exothermic assisted synthesis of pure alumino-silicates and magnesium-aluminates based ceramics has very few publications. The utilization of the aluminium powder as the raw material for the mullite synthesis is presented in the studies of H. Balmori-Ramirez et al [3] and A. Esharghawi et al [4]. In the present study of A. Esharghawi et al [5] porous mullite-based bodies were produced by SHS starting from the kaolinitic clay, Al and Mg powder mixtures.…”

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confidence: 84%

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Reaction heat potential utilization in mullite and spinel based ceramics synthesis and sintering

et al. 2016

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Present work studies the potential of the utilization of the heat released from exothermic reactions in ceramic synthesis and sintering. For example the initialization of the endothermic reaction of the mullite formation is studied with heat releasing co-reactions. Exothermically reactive raw material (aluminium powder) is examined for external energy saving ceramic synthesis. KEYWORDS: exothermic reactions, mullite synthesisPrzeanalizowano możliwości wykorzystania ciepła pochodzącego z reakcji egzotermicznej podczas syntezy i spiekania materiałów ceramicznych. Przykładowo zainicjowanie reakcji endotermicznej podczas formowania się mullitu analizowano wraz z ciepłem uwalnianym w reakcjach towarzyszących. Surowy materiał reaktywny egzotermicznie (proszek aluminiowy) poddano badaniom w celu obniżenia energii zewnętrznej niezbędnej podczas syntezy ceramiki. SŁOWA KLUCZOWE: reakcje egzotermiczne, synteza mullitu Porous ceramic materials for high-temperature applications are of great interest today (insulators, catalyst supports, filters etc.). Typically the synthesis of the technical ceramics, such as mullite and spinel based, requires high temperature and long sintering time. Traditional production routes consume a lot of energy and have long processing times, which increases the cost of products and consequently have high environmental burden. Therefore lower external energy requiring processing routes are sought for. Self-propagating High-temperature Synthesis (SHS) is offering one, energy efficient and rapid route for making advanced composites and intermetallic compounds and due to the low external energy consumption, SHS is feasible processing method even for environmental protection [1-2]. The SHS process is traditionally limited only to highly exothermic reactions where the released combustion energy is exploited. However, exothermic assisted synthesis of pure alumino-silicates and magnesium-aluminates based ceramics has very few publications. The utilization of the aluminium powder as the raw material for the mullite synthesis is presented in the studies of H. . In the present study of A. Esharghawi et al. [5] porous mullite-based bodies were produced by SHS starting from the kaolinitic clay, Al and Mg powder mixtures. Pure mullite has not been obtained but Si and Al in metallic phases, quartz, α-alumina and MgAl2O4 spinel were present in addition to the mullite phase. In the study of G. Xanthopoulou and G. Vekinis [6], MgO/MgAl2O4 refractories were produced by SHS resulting the spinel content up to 100%. The starting materials included Al and Mg powders mixed with various oxides and salts. Experimental procedureIn this study, the endotermic reaction of the synthesis combined with the in-situ exothermic reactions are examined and compared to the traditional sintering. Kaolin (Al2O3·2SiO2·2H2O), aluminium oxide hydroxide (AlO(OH)) and aluminium (Al) powders were selected as raw materials for the stoichiometric 3:2 mullite (3Al2O3·2SiO2) synthesis. Magnesium hydroxide (Mg(OH)2), aluminium oxide (Al2O3) and Al...

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Section: Resultssupporting

confidence: 84%

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confidence: 84%

Reaction heat potential utilization in mullite and spinel based ceramics synthesis and sintering

et al. 2016

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“…The exceptional scientific and technical importance of mullite can be explained on the basis of their characteristics, to be a stable crystalline phase from room temperature up to about 1880 C at atmospheric pressure (Mileiko et al 2009;Esharghawi et al 2009;Schneider et al, 2008, Skoog et al, 1988, have in their properties the main reason for your application, such as low thermal expansion (20 / 200 C = 4 x 10 -6 K -1 ), low conductivity thermal (k = 2.0 Wm -1 K -1 ), low density (3.17 g/cm 3 ), low dielectric constant ( = 6.5 at 1 MHz), excellent wear resistance and high resistance at temperatures suitable for use (Esharghawi et al 2009;Schneider & Komarneni, 2005;Schneider, 1994;Meng et al 1983;Bartscher et al 1999;Viswabaskaran et al, 2003), and the fact that the raw materials for its production (eg alumina, silica, aluminum silicates, sheet silicates rich in Al 2 O 3 , clays, etc.) are widely found in nature (Schneider et al, 2008).…”

Section: Using Kaolin Waste As Raw Materials For Obtaining Mullitementioning

confidence: 99%

The Kaolin Residue and Its Use for Production of Mullite Bodies

Brasileiro¹,

Rodrigues²,

Menezes³

et al. 2012

Sustainable Development - Energy, Engineering and Technologies - Manufacturing and Environment

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“…The most common one is by using agents as pore former such as graphite [28], Al and Mg metallic powders [29] and calcite (CaCO3) [30] to control or help in forming pores with suitable distribution and sizes. Furthermore, another technique to produce porous mullite is through the removal of cristobalite produced from calcined bodies of sintered kaolin by leaching with strong alkali solutions [31,32].…”

Section: Introductionmentioning

confidence: 99%

Facile Hydrothermal Synthesis of Zeolitic ANA Membrane from Raw Kaolin

Khumbudda

Chaisena

Rangsriwatananon

2016

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Abstract. The present paper reported a preparation of zeolitic ANA (analcime) membrane on porous ceramic support by in situ synthesis method using raw kaolin as SiO2 and Al2O3 source with the molar composition of Al2O3 • 2.3SiO2 • 3.6Na2O • 140.4H2O at hydrothermal temperature 200 ºC. X-ray diffraction (XRD) and scanning electron microscope (SEM) were used to characterize the ANA membrane. The effects of aging time and hydrothermal time on the synthesis were investigated. The porous ceramic supports were prepared by adding 10.0 wt% of cristobalite and varying an amount of pore formers (activated carbon and calcite) by sintering at 1400 ºC. This resulted in the high crystallinity of ANA observed on the support which was prepared from mixing of 2.5 wt% of activated carbon and 2.5 wt% of calcite. In addition to aging, it was observable that small crystals seemed to spread completely on the support within 3 days of aging. It seems that the longer the hydrothermal time is, the more obvious the crystals tightly bound with the support becomes.

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Contribution to porous mullite synthesis from clays by adding Al and Mg powders

Cited by 55 publications

References 26 publications

Reaction heat potential utilization in mullite and spinel based ceramics synthesis and sintering

Reaction heat potential utilization in mullite and spinel based ceramics synthesis and sintering

The Kaolin Residue and Its Use for Production of Mullite Bodies

Facile Hydrothermal Synthesis of Zeolitic ANA Membrane from Raw Kaolin

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