Aqueous leachability of metakaolin-based geopolymers with molar ratios of Si/Al=1.5–4

Aly, Zaynab; Vance, E. R.; Perera, D. S.; Hanna, John V.; Griffith, Christopher S.; Davis, Joel; Durce, Delphine

doi:10.1016/j.jnucmat.2008.06.015

Cited by 86 publications

(48 citation statements)

References 11 publications

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“…After 7 days, all paste and mortar specimens were exposed to various solutions, they were fully immersed in the solutions of an amount about 50 dm 3 and in water about 1 m 3 . The solutions were: HCl, NaOH, and water (at pH respectively equal to 1, 2 (HCl); 12, 13, and 14 (NaOH); and about 7 (water)).…”

Section: Testing and Characterisationmentioning

confidence: 99%

“…Al V and Al VI had a large increase from 0% to 35% and from 11,35% to 24 %, respectively while Al IV decreased strongly from 88,65% to 41%. Because %Q 3 [24] is minor, so Q 3 [24] is approximately considered as Q 3 …”

Section: The Influence Of Ph On Structural Change As Determined By Nmrmentioning

confidence: 99%

“…Na can leach easily as a free Na + ion in water that reacts in turn with CO 2 present in the air to make soluble Na 2 CO 3 . Consequently, the leachability of geopolymer in water was investigated to optimize the composition for the immobilization of components to reduce leaching [3]. In addition, acid corrosion of the hardened paste of the geopolymer cement in solutions of nitric acid and sulphuric acid has been discussed in previous publications [4][5][6][7].…”

Section: Introductionmentioning

confidence: 99%

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The influence of ambient pH on fly ash-based geopolymer

Nguyen

Škvára

2016

Cement and Concrete Composites

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Section: Testing and Characterisationmentioning

confidence: 99%

Section: The Influence Of Ph On Structural Change As Determined By Nmrmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The influence of ambient pH on fly ash-based geopolymer

Nguyen

Škvára

2016

Cement and Concrete Composites

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“…The interaction of Cs with geopolymer paste was studied by varying the molar Al:x (x=Na or K) ratio while keeping the molar Al:Si ratio constant at 2 [39]. The molar Al:x ratio was varied between 0.7 and 1.3 and the corresponding leaching results are shown in Figures 3 and 4.…”

Section: Leaching Of Cs From Geopolymersmentioning

confidence: 99%

Encapsulation of Cs/Sr contaminated clinoptilolite in geopolymers produced from metakaolin

Kuenzel

Cisneros

Neville

et al. 2015

Journal of Nuclear Materials

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“…The alkali solutions (activators) of AAM are typically a mixture of NaOH, KOH, Na 2 SiO 3 and K 2 SiO 3 . It is apparent that the pore solution of AAM contains high concentration of alkali metal cations, typically more than 500 mM in several cases even exceeding 1 M (2), and leaching rate for Na + is high, reaching tens of g/m 2 /day (tens of μm/day) for the first few weeks and decreasing over time (3). Xie and Ozbakkaloglu observed the leaching of dense low-calcium fly and bottom ash-based geopolymers and described it as efflorescence and the diffusion of alkali salts from the structure of the material (4).…”

Section: Introductionmentioning

confidence: 99%

Porous alkali activated materials with slow alkali release dynamic. Role of composition

Būmanis

Bajāre

2018

Mater. construcc.

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Alkali activated materials (AAM) based on calcined metakaolin or illite clay together with waste by-products, such as waste glass or aluminium scrap recycling waste, were tested as value-added materials for pH stabilization in biogas technology where decrease of pH should be avoided. Porous materials with ability to slowly leach alkalis in the water media thus providing continuous control of the pH level were obtained. XRD, FTIR, SEM and titration methods were used to characterize AAM and their leaching properties. It is clear that composition of the material has an important effect on the diffusion of alkali from structure. Namely, higher Si/Al and Na/Al molar ratios may increase pore solution transfer to the leachate. The leaching rate of alkalis from the structure of AAM is high for the first few days, decreasing over time. It was possible to calculate the buffer capacity from the mixture design of AAM. RESUMEN: Materiales activados alcalinamente porosos con liberación lenta de álcalis. Efecto de la composición.En este estudio se han ensayado materiales activados alcalinamente (AAM) basados en metacaolín o arcilla de ilita junto con subproductos tales como residuos de vidrio o aluminio reciclado, como materiales con valor añadido para la estabilización del pH en tecnologías de biogás donde se debe evitar la disminución del pH . Se obtuvieron materiales porosos con capacidad para lixiviar lentamente los álcalis en medios acuosos, proporcionando así un control continuo del nivel de pH. Se utilizaron técnicas de DRX, FTIR, SEM y métodos de tritación para caracterizar los AAMs y sus propiedades de lixiviación. La composición del material tiene un efecto importante en la difusión del álcali de la estructura. Es decir, mayores relaciones molares de Si / Al y Na / Al pueden aumentar la transferencia de la solución del poro al lixiviado. La tasa de lixiviación de los álcalis desde la estructura de los AAMs es alta durante los primeros días, disminuyendo con el tiempo. Se ha calculado la capacidad del efecto tampón a partir del diseño de mezcla de AAM.Palabras clave: Cemento activado alcalinamente; Tratamiento de residuos; Difusión; Microestructura, pH ORCID ID: G. Bumanis

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Aqueous leachability of metakaolin-based geopolymers with molar ratios of Si/Al=1.5–4

Cited by 86 publications

References 11 publications

The influence of ambient pH on fly ash-based geopolymer

The influence of ambient pH on fly ash-based geopolymer

Encapsulation of Cs/Sr contaminated clinoptilolite in geopolymers produced from metakaolin

Porous alkali activated materials with slow alkali release dynamic. Role of composition

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