Formation process of Na-X zeolites from coal fly ash

Tanaka, Hidekazu; Matsumura, Shuichi; Hino, Ryozi

doi:10.1023/b:jmsc.0000016169.85449.86

Cited by 46 publications

(30 citation statements)

References 12 publications

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“…BK3Z also contained P-type zeolite and hydroxysodalite. Thus, the commercial X-type zeolite appeared to have transformed into the more stable P-type zeolite and hydroxysodalite [14] during alkali-activation treatment. These results showed that the addition of commercial X-type zeolite into the starting material did not increase the content of X-type in the final bulk material.…”

Section: Resultsmentioning

confidence: 99%

Characterization of Zeolite in Zeolite-Geopolymer Hybrid Bulk Materials Derived from Kaolinitic Clays

et al. 2013

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Zeolite-geopolymer hybrid materials have been formed when kaolin was used as a starting material. Their characteristics are of interest because they can have a wide pore size distribution with micro- and meso-pores due to the zeolite and geopolymer, respectively. In this study, Zeolite-geopolymer hybrid bulk materials were fabricated using four kinds of kaolinitic clays (a halloysite and three kinds of kaolinite). The kaolinitic clays were first calcined at 700 °C for 3 h to transform into the amorphous aluminosilicate phases. Alkali-activation treatment of the metakaolin yielded bulk materials with different amounts and types of zeolite and different compressive strength. This study investigated the effects of the initial kaolinitic clays on the amount and types of zeolite in the resultant geopolymers as well as the strength of the bulk materials. The kaolinitic clays and their metakaolin were characterized by XRD analysis, chemical composition, crystallite size, 29Si and 27Al MAS NMR analysis, and specific surface area measurements. The correlation between the amount of zeolite formed and the compressive strength of the resultant hybrid bulk materials, previously reported by other researchers was not positively observed. In the studied systems, the effects of Si/Al and crystalline size were observed. When the atomic ratio of Si/Al in the starting kaolinitic clays increased, the compressive strength of the hybrid bulk materials increased. The crystallite size of the zeolite in the hybrid bulk materials increased with decreasing compressive strength of the hybrid bulk materials.

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Section: Resultsmentioning

confidence: 99%

Characterization of Zeolite in Zeolite-Geopolymer Hybrid Bulk Materials Derived from Kaolinitic Clays

et al. 2013

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“…Understanding the crystallization mechanisms of zeolites can conduct to exploit efficient routes to synthesize them. Although numerous works have attempted to understand the mechanisms of zeolites and solution transport and solid phase transformation mechanisms are proposed [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18], relatively few studies have been performed on the elucidation of the mediumrange structures and their changes during zeolite crystallization. As it is reported in the previous study, the short-range order is represented by the local coordination polyhedra, while the medium-range structure can be regarded as the next highest level of structural organization beyond the short-range order [19].…”

Section: Introductionmentioning

confidence: 99%

Changes of medium-range structure in the course of crystallization of zeolite omega from magadiite

Cui

Zhang

Liu

et al. 2014

Microporous and Mesoporous Materials

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“…Zeolites with different structure are known to be obtained by synthesis [2][3][4][5][6][7]. They are either synthesized from aluminosilicate hydrogel or by conversion of clay minerals.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and Characterization of High Aluminum Zeolite X from Technical Grade Materials

Masoudian¹,

Sadighi²,

Abbasi³

2013

Bull. Chem. React. Eng. Catal.

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Zeolites are widely used as ion exchangers, adsorbents, separation materials and catalyst due to their welltailored and highly-reproducible structures; therefore, the synthesis of zeolite from low grade resources can be interested. In the present work, high aluminum zeolite X was prepared from mixing technical grade sodium aluminate and sodium silicate solutions at temperatures between 70°C and 100°C. The synthesized zeolite X was characterized by SEM and X-ray methods according to ASTM standard procedures. The results showed that aging of the synthesis medium at the room temperature considerably increased the selectivity of zeolite X formation. On the other hand, high temperature of reaction mixture during crystallization formed zeolite A in the product; therefore, it decreased the purity of zeolite X. In addition, it was found that increasing H2O/Na2O and decreasing Na2O/SiO2 molar ratios in the reaction mixture resulted product with higher purity.

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Formation process of Na-X zeolites from coal fly ash

Cited by 46 publications

References 12 publications

Characterization of Zeolite in Zeolite-Geopolymer Hybrid Bulk Materials Derived from Kaolinitic Clays

Characterization of Zeolite in Zeolite-Geopolymer Hybrid Bulk Materials Derived from Kaolinitic Clays

Changes of medium-range structure in the course of crystallization of zeolite omega from magadiite

Synthesis and Characterization of High Aluminum Zeolite X from Technical Grade Materials

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