Crystal-size control and characterization of Na-4-mica prepared from kaolinite

Kodama, Tetsuya; Harada, Yukihiro; Ueda, Masahito; Shimizu, Ken‐ichi; Shuto, Kenji; Komarneni, Sridhar; Hoffbauer, Wilfried; Schneider, Hartmut

doi:10.1039/b009418h

Cited by 19 publications

(31 citation statements)

References 14 publications

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“…For example, clintonite (Ca(Mg 2 Al)(SiAl 3 )O 10 (OH) 2 ), margarite (CaAl 2 (Si 2 Al 2 )O 10 (OH) 2 ) and kinoshitalite (BaMg 3 (Si 2 Al 2 )O 10 (OH) 2 ), are known as brittle micas [3]. In addition, highly charged sodium fluorophlogopite mica (Na 4 Mg 6 Al 4 Si 4 O 20 F 4 ), called "Na-4-mica", has been synthesized by many kinds of solid-state reactions [4][5][6][7][8][9][10][11][12][13][14]. Also, it has been found that electrical conductivity of the "Na-4-mica" is 4.3×10 -4 S/cm at 650ºC, which is much higher than that of the ordinary Na-type fluorophlogopite (Na 2 Mg 6 Al 2 Si 6 O 20 F 4 ) [14].…”

Section: Introductionmentioning

confidence: 99%

Crystallization process and some properties of novel transparent machinable calcium-mica glass-ceramics

Taruta

Sakata

Yamaguchi

et al. 2008

Ceramics International

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Bulk glass having a calcium-mica composition (Ca 0.5 Mg 3 AlSi 3 O 10 F 2 ) is homogeneous glass. The crystallization mechanism of the mica is surface crystallization and transparency is lost completely when crystallization occurs on the surface. In this study, by decreasing SiO 2 and increasing CaO and Al 2 O 3 from the chemical composition of Ca 0.5 Mg 3 AlSi 3 O 10 F 2 , and moreover by replacing a small amount of K 2 O instead of CaO, the phase separation appears in the glasses. Because of this phase separation, the mica begins to be crystallized not only on the surface but also in the bulk at lower temperatures. Consequently, the novel transparent machinable mica glass-ceramic can be obtained by heating the glasses having the chemical composition of Ca 0.6 Mg 3 Al 1.2 Si 2.8 O 10 F 2 and K 0.01 Ca 0.595 Mg 3 Al 1.2 Si 2.8 O 10 F 2 . As a larger amount of calcium-mica is separated, the bending strength decreases and the fracture toughness increases. Furthermore, by replacing K + ion instead of Ca 2+ ion in the interlayer of calcium-mica, the interlayer bonding strength becomes high, resulting in the increase of the bending strength.

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Section: Introductionmentioning

confidence: 99%

Crystallization process and some properties of novel transparent machinable calcium-mica glass-ceramics

Taruta

Sakata

Yamaguchi

et al. 2008

Ceramics International

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“…The lattice spacings of the mica formed at 900-1150ºC almost corresponded to those of anhydrous Na-4-mica synthesized by Paulus et al [4], Franklin and Lee [5], Komarneni et al [6,9] and Kodama et al [6][7][8]10,11]. That is, Na-4-mica could be obtained by new and simple method which was the solid-state reaction of the mixtures of MgO, Al 2 O 3 , SiO 2 and NaF in the sealed container, and besides, it was synthesized at about the same firing temperature (900ºC) for shorter firing time, comparing with that obtained by other methods [3][4][5][6][7][8][9][10][11][12][13]. SEM photographs of fracture surfaces of the Na4 specimen fired at 900ºC and 1100ºC are shown in Fig.…”

Section: Resultsmentioning

confidence: 75%

“…One of the reasons why On the other hand, the Na-4-mica has theoretically high ion-exchange capacity. So it has been synthesized by using natural materials such as augite [3] or kaolinite [6,[8][9][10]11,13], by sol-gel method [4,5] or by using NaCl melt [12] and its cation exchange properties have been investigated [4][5][6][7][8][9][10]13]. However, there are no studies on its ionic conductivity.…”

Section: Introductionmentioning

confidence: 99%

New synthetic method and ionic conductivity of Na-4-mica

et al. 2006

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If interlayer cations of micas can move in the interlayer, the micas show ionic conductivity.However, K-type fluorophlogopite (KMg 3 AlSi 3 O 10 F 2 ) which is the representative synthetic mica and the main crystal of mica ceramics is known as an electrical insulator. If interlayer cations of micas are smaller than K + ion which is the interlayer cation of K-type fluorophlogopite and a larger amount of cation is stuffed in the interlayer, the micas have a higher possibility as ionic conductors. As one of such micas, highly charged sodium fluorophlogopite mica (Na 4 Mg 6 Al 4 Si 4 O 20 F 4 ·xH 2 O) which is called "Na-4-mica" is nominated. But there are no studies on its ionic conductivity. In this study, Na-4-mica could be synthesized by new and simple method which consisted of mixing of MgO, Al 2 O 3 , SiO 2 and NaF, calcination, sieving, compaction and firing in a sealed platinum container. The conductivity of the obtained Na-4-mica increased with an increase in temperature and reached 4.3×10 -4 S/cm at 650ºC.

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“…1,2,3,4,5,6,7 Due to their high CEC (theoretically up to 468 meq/100g), applications like radioactive cation fixation or removal of heavy metal cations from waste water were proposed. 8,9,10,11,12,13 In those high charged synthetic micas, the layers bear a high permanent negative charge compensated by counterions located between them (interlayer space).…”

Section: Toc Graphic Introductionmentioning

confidence: 99%

Interaction of Hydrated Cations with Mica-n (n = 2, 3 and 4) Surface

et al. 2014

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ABSTRACT. High charged swelling micas, with layer charge comprised between 2 and 4, has been found to readily swell with water and that complete cation exchange (CEC) can be achieved. Due to their high CEC, applications like radioactive cation fixation or removal of heavy metal cations from waste water were proposed. Their applicability can be controlled by the location of the interlayer cation in a confined space with a high electric field. In synthetic brittle micas, the interlayer cation has a low water coordination number; therefore their coordination sphere would be completed by the basal oxygen of the tetrahedral layer as innersphere complexes (ISC). However, no direct evidence of these complexes formation in brittle micas has been reported yet. In this contribution, we mainly focus on the understanding the mechanisms that provoke the formation of ISC in high charge swelling micas, Mica-n. A whole series of cations (X) were used to explore the influence of the charge and size of the interlayer cation. Three brittle swelling micas, Mica-n (n=4, 3 and 2), were selected in order to analyze the influence of the layer charge in the formation of ISC. The contribution of the ISC has been analyzed thorough the evolution of the 060 reflection and the changes in the short-range order of the tetrahedral cations will be followed 29 Si and 27 Al MAS-NMR. The results showed that ISC was favored in X-Mica-4 and that provoked a high distortion angle between the Si-Al tetrahedra. When the content of aluminum decreases, the electrostatic forces between the layers are relaxed, and the hydrated cations did not interact so strongly with the tetrahedral sheet, having the opportunity to complete their hydration sphere.

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Crystal-size control and characterization of Na-4-mica prepared from kaolinite

Cited by 19 publications

References 14 publications

Crystallization process and some properties of novel transparent machinable calcium-mica glass-ceramics

Crystallization process and some properties of novel transparent machinable calcium-mica glass-ceramics

New synthetic method and ionic conductivity of Na-4-mica

Interaction of Hydrated Cations with Mica-n (n = 2, 3 and 4) Surface

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