The effect of alkali concentration and solid/liquid ratio on the hydrothermal synthesis of zeolite NaA from natural kaolinite

Alkan, Mahir; Hopa, Çiğdem; Yılmaz, Zürriye; Güler, Halil

doi:10.1016/j.micromeso.2005.07.008

Cited by 232 publications

(123 citation statements)

References 17 publications

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“…22) On the other hand, the bands of weak intensity detected at 721, 694 and 663 cm À1 in the product obtained at an extended sonicating time of 240 min are in good agreement with the characteristic bands for HS structure. 23) Ultrasonic irradiation would also facilitate the preparation of very fine and well dispersed crystals. Figure 6 shows the SEM photographs and their PSDs of the 120-min sonicated and 240-min heated products, respectively.…”

Section: Resultsmentioning

confidence: 99%

Sonochemical Synthesis of Zeolite A from Metakaolinite in NaOH Solution

2010

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Sonochemical synthesis of zeolite A has been conducted by ultrasonic irradiation of mixtures of metakaolinite and NaOH solution. The hydrothermal synthesis at conventional synthesis conditions was undertaken to determine the sonochemical reliability. The enhancement of nucleation and crystallization rate of zeolite A was achieved by ultrasound. In the ultrasonic field, zeolite A once formed in the suspension has been converted into hydroxysodalite and losod as sonicating proceeded. Comparing the results with those of conventional methods, this heterogeneous reaction was particularly accelerated by ultrasound, leading to improved reactivity of solid reactant through intensive mixing. The use of ultrasound enables us to prepare well-dispersed fine zeolite A particles with mean particle size of around 1 mm. The cation exchange capacity values of the products increased as the synthesis reaction for zeolite A proceeded. The high solid concentration in the suspension, however, hindered the ultrasound from intense agitating, resulting in the decrease of zeolite A yield.

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Section: Resultsmentioning

confidence: 99%

Sonochemical Synthesis of Zeolite A from Metakaolinite in NaOH Solution

2010

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“…For example, Alkan et al (2005) 8 studied the influence of NaOH concentration and the solid/liquid ratio on the synthesis of zeolite NaA using a metakaolin obtained at 900 °C for 2 h. The synthesis time was fixed at 2 h, with the best concentration of 4 mol/L NaOH used. However, by using a concentration of 6 mol/L, the best solid/liquid ratios obtained for the synthesis were from 1.25 to 5.0 g in 25 mL at 2 h with a synthesis temperature of 105 °C.…”

Section: Selim and El-maksoud (2004)mentioning

confidence: 99%

Study on the NaOH/metakaolin Ratio and Crystallization Time for Zeolite a Synthesis from Kaolin Using Statistical Design

et al. 2017

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The NaOH/metakaolin ratio and crystallization time were studied for the synthesis of zeolite NaA from a sample of kaolin from a Capim mine. The tests were carried out by using statistical design with axial points and replication of the central point. The samples obtained were characterized by X-ray diffraction (DRX), scanning electron microscopy and chemical analysis using a microprobe EPMA. The results showed that there is a relationship between the amount of NaOH added and crystallization time. The tests carried out using the lowest NaOH/metakaolin ratio (0.5) and the shortest time (4 h) produced a non-crystalline material. On the other hand, increasing the NaOH/metakaolin ratio and the crystallization time led to the formation of a NaA phase with a high structural level, but with the presence of a sodalite phase as an impurity.

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“…As argilas, principalmente o caulim, são utilizadas em diferentes estudos envolvendo a síntese de zeólitas, tais como: zeólita A [2][3][4][5][6][7][8], zeólitas do tipo faujasita X [9,10 ] e Y [11]. Outras zeólitas como a ZSM-5 já foram sintetizadas a partir de cinzas de casca de arroz [12][13][14][15][16] e de argilas [17].…”

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Síntese de zeólitas utilizando resíduo sílico-aluminoso proveniente do processo de extração de lítio

et al. 2013

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ResumoUtilizou-se um resíduo sílico-aluminoso como fonte de SiO 2 e Al 2 O 3 para síntese de zeólitas. O resíduo é um subproduto do processo de extração de lítio do ß-espodumênio. Os produtos sintetizados caracterizaram-se por uma mistura de fases zeolíticas e compostos presentes no resíduo, que não foram solubilizados. Quando a relação Si/ Al foi ajustada para 1, foi formada uma mistura de fases zeólita A + sodalita e zeólita NaP + sodalita. A mistura de fases zeólita A + sodalita foi obtida deixando o resíduo sílico-aluminoso em agitação por 2 h a 80 o C, antes da adição de aluminato de sódio e posterior cristalização por 4 h. Quando a mistura resíduo e NaOH ficou em estático a 100 o C por 4 h, nesta mesma etapa, o produto formado foi uma mistura de sodalita + zeólita NaP. O aumento da razão Si/Al para 3,2, uma etapa de envelhecimento e maiores tempos de cristalização, levou a formação de uma mistura de fases NaP1 e quartzo pertencente ao resíduo. Palavras-chave: resíduo sílico-aluminoso, zeólita A, sodalita, zeolita NaP, NaP1. Abstract In this study we used a silico-aluminous residue as a source of SiO

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The effect of alkali concentration and solid/liquid ratio on the hydrothermal synthesis of zeolite NaA from natural kaolinite

Cited by 232 publications

References 17 publications

Sonochemical Synthesis of Zeolite A from Metakaolinite in NaOH Solution

Sonochemical Synthesis of Zeolite A from Metakaolinite in NaOH Solution

Study on the NaOH/metakaolin Ratio and Crystallization Time for Zeolite a Synthesis from Kaolin Using Statistical Design

Síntese de zeólitas utilizando resíduo sílico-aluminoso proveniente do processo de extração de lítio

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