Silicon-29 and aluminum-27 NMR study of zeolite formation from alkali-leached kaolinites:  influence of thermal preactivation

Madani, A.; Aznar, A.; Sanz, J.; Serratosa, José M.

doi:10.1021/j100365a046

Cited by 128 publications

(63 citation statements)

References 6 publications

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“…metakaolin used in this study shows a product of low crystallinity due to the presence of an amount of quartz (SiO2), which is identified by a peak at ~25° (2θ) [51,52]. The XRD pattern for sample 16 before and after casting belongs to the crystalline SiO2 phase, which proves that traces of quartz are already present in MK precursor in MK-based geopolymers [53,54].…”

Section: X-ray Diffraction (Xrd)mentioning

confidence: 61%

Development of Green Geopolymer Using Agricultural and Industrial Waste Materials with High Water Absorbency

et al. 2017

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Abstract:Geopolymer is a promising porous material that can be used for evaporative cooling applications. Developing a greener geopolymer using agricultural and industrial wastes is a promising research area. In this study, we utilize rice husk (RH), rice husk ash (RHA), metakaolin (MK), ground granulated blast furnace slag (GGBS), and palm oil fuel ash (POFA) to prepare geopolymer pastes, with alkali liquid as an activator. Many geopolymer samples have been prepared as per the Design of Experimental software (DOE), and its corresponding response surface mode and central composite design and later they were characterized. The samples were cured in an oven for 2 h at 80 • C, and thereafter stored at room temperature (~25-30 • C) prior to being tested for its water absorption and compressive strength. The effect of the different composition of precursors on water absorption, density, porosity, and the compressive strength of the prepared geopolymers have been investigated. The results showed that the compressive strength of geopolymers is directly proportional to the ratio of the alkali liquid. Post-optimization, the best geopolymer paste mixture was confirmed to contain 10% of RH, 15% RHA, 35% MK, 10% POFA and 30% of GGBS, with 72% desirability for maximum water absorption (~38%) and compressive strength (4.9 MPa). The results confirmed its applicability for evaporative cooling.

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Section: X-ray Diffraction (Xrd)mentioning

confidence: 61%

Development of Green Geopolymer Using Agricultural and Industrial Waste Materials with High Water Absorbency

et al. 2017

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“…Metakaolin (MK) is prepared from kaolin as it is described by previous researchers (39). In order to compare the different properties of geopolymers with other commercial materials, samples of Ordinary Portland Cement (OPC) were prepared using commercial Portland Cement Type II (CEM II/B-L 32.5 N according to EN 197-1 (40)).…”

Section: Methodsmentioning

confidence: 99%

Properties of fly ash and metakaolín based geopolymer panels under fire resistance tests

Luna-Galiano¹,

Cornejo²,

Leiva³

et al. 2015

Mater. construcc.

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This paper presents the results of a study about the effect of fire on geopolymer paste composed of fly ashes, metakaolin and sodium silicate. 2 cm thick, 28 cm high and 18 cm wide panels were filled with the paste obtained. After 28 days of curing at 20 °C and 45% of relative humidity, different tests were carried out in the geopolymers: physico-chemical (density, water absorption, porosity), mechanical (flexural and compressive strength), fire resistance and environmental (leaching and radioactivity). The panels manufactured have been compared with other commercial panels in order to determine the recycling possibilities of fly ashes in manufacturing new fire-insulating geopolymers. The panels obtained can be utilized for the production of interior wall materials, with a good physical, mechanical, fire resistant properties without any environmental problem. RESUMEN: Propiedades de paneles geopoliméricos basados en ceniza volante y metacaolín bajo ensayos de resistencia al fuego.Este documento presenta los resultados de un estudio sobre el efecto del fuego sobre pastas de geopolímeros compuestas de cenizas volantes, metacaolín y silicato sódico. Con la pasta obtenida se han rellenado paneles de dimensiones 2 cm de espesor, 28 cm de altura y 18 cm de ancho. Tras 28 días de curado a 20 °C y un 45% de humedad relativa, diferentes ensayos fueron realizados en los geopolímeros obtenidos: fisicoquímicos (densidad, absorción de agua, porosidad), mecánicos (resistencia a compresión y a flexión), de resistencia al fuego y medioambientales (lixiviación y radioactividad). Los paneles fabricados han sido comparados con paneles comerciales para determinar las posibilidades de reciclaje de las cenizas volantes para la fabricación de nuevos productos geopoliméricos con propiedades aislantes al fuego. Los paneles obtenidos pueden ser utilizados para la producción de paredes interiores, con buenas propiedades físicas, mecánicas y de resistencia al fuego sin ningún problema medioambiental.

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“…In both series, thermal treatment produced a shift in the adsorption band from 537 cm-1 (Fso ~ and FFes0o) to 800 cm -1 (F750, 17900, FFe750 and FFeg00) , which was in agreement with the octahedral-to-tetrahedral A1 coordination change (Madani et al 1990) and was attributed to kaolinite-metakaolinite transformation (Percival et al 1974). This tetrahedral AI coordination was stable up to 980 ~ where the 800-cm ~ absorption band disappeared and a new band at 550 cm -t occurred, assigned to octahedral AI.…”

Section: ~ Ffe980mentioning

confidence: 81%

“…Additionally, studies performed by Madani et al (1990) indicated that the A1 coordination number in the raw material played an important role in zeolite conversion from kaolins. This A1 coordination was affected by thermal treatment.…”

Section: Introductionmentioning

confidence: 99%

Iron Influence in the Aluminosilicate Zeolites Synthesis

Basaldella

Sánchez²,

Tara

1998

Clays and clay miner.

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Abstract--The level of Fe impurities in 2 well-crystallized kaolinites was modified (by addition or chemical removal treatment) to analyze the Fe influence in the aluminosilicate zeolite synthesis.The original and modified clays were heat-treated in order to change their reactivity for zeolite A synthesis, and their thermal transformations were studied by X-ray diffraction (XRD), determination of point of zero charge (PZC) and infrared (IR) techniques. It was established that many structural changes took place, regardless of the Fe clay content. Furthermore, the presence of Fe species in alkaline solution or in the solid phase did not seem to greatly influence the zeolite crystallization, because only small differences in the conversion values among samples with different Fe contents were registered. The crystallization process seemed to be related mainly to A1 coordination changes produced by the thermal and Fe removal treatments used.

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Silicon-29 and aluminum-27 NMR study of zeolite formation from alkali-leached kaolinites: influence of thermal preactivation

Cited by 128 publications

References 6 publications

Development of Green Geopolymer Using Agricultural and Industrial Waste Materials with High Water Absorbency

Development of Green Geopolymer Using Agricultural and Industrial Waste Materials with High Water Absorbency

Properties of fly ash and metakaolín based geopolymer panels under fire resistance tests

Iron Influence in the Aluminosilicate Zeolites Synthesis

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