Heating temperature effect on the hygroscopicity of expanded vermiculite

Feng, Jinpeng; Liu, Meng; Mo, Wei; Su, Xiujuan

doi:10.1016/j.ceramint.2021.05.259

Cited by 17 publications

(13 citation statements)

References 20 publications

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“…Otherwise, the maximum water absorption content was very close 130 mg/g for U-900 for 24 h, followed of 127.1 mg/g for U-900 for 7.5 h and 121.5 mg/g for U-800 for 1.5 h. These values were much higher than those shown in the humidity absorption experiments carried out by Feng et al [2]. According to Melero and Li [31,32], expanded commercial vermiculites could be a suitable hygroscopic material, due to their efficient water absorption, and mainly those with a composition similar to Ugandan vermiculite.…”

Section: Discussioncontrasting

confidence: 57%

“…The expansibility of Ugandan vermiculite is much lower than that of Xinjiang (China) [2] at any of the temperatures used. The reason is due to differences in composition of the two vermiculites, basically to K 2 O and water contents.…”

Section: Discussionmentioning

confidence: 77%

“…In order to use vermiculite as roof and floor insulation in a house, it know its water retention capacity. So far, some research has been carried havior of vermiculite in in a controlled humid atmosphere [2], and with verm with allophane or other materials [11]. The objective of this work was, on th investigate whether the water absorption capacity of expanded vermiculite different temperatures and by microwave irradiation, is suitable for use it as material; on the other hand, to study the effect of water immersion on verm Several techniques were used for the characterization: The compositio ple was obtained using X-ray fluorescence (XRF); the expansibility of the different temperatures and with irradiation with microwaves was obtained samples at different temperatures with an electric muffle furnace and irr with microwaves into microwave oven, respectively; X-ray diffraction (X for the identification of the mineral composition; thermal behavior was o thermal gravimetric (TG) and analyses textural parameters with Brunauer-(BET).…”

Section: Methodsmentioning

confidence: 99%

“…The other effective way is to improve energy efficiency, which can be realized through the use of thermal insulating materials with high performance [2].…”

Section: Introductionmentioning

confidence: 99%

“…In order to use vermiculite as roof and floor insulation in a house, it is necessary to know its water retention capacity. So far, some research has been carried out on the behavior of vermiculite in in a controlled humid atmosphere [2], and with vermiculite mixed with allophane or other materials [11]. The objective of this work was, on the one hand, to investigate whether the water absorption capacity of expanded vermiculite, by heating at different temperatures and by microwave irradiation, is suitable for use it as a hygroscopic material; on the other hand, to study the effect of water immersion on vermiculite.…”

Section: Introductionmentioning

confidence: 99%

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Effect of Water Immersion on Raw and Expanded Ugandan Vermiculite

Marcos

2021

Minerals

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Effect of water immersion at different times (from 1/2h to 24 h) on raw and expanded vermiculite from Uganda was investigated. The expansion was carried out by electrical heating at different temperatures and by irradiation with microwaves. After, the expansibility (k) and the water absorption content (WA) were obtained and the samples were characterized. The elemental and mineral composition was determined by X-ray fluorescence and X-ray diffraction, respectively; the thermal behavior by thermal gravimetric analyses; and the textural parameters by BET. The expansibility of Ugandan vermiculite is relatively lower than the other commercial vermiculites due basically to its lower K2O content (0.36%) and higher water content (about 20%). The water absorption capacity of samples significantly increased with the increase in heating temperature. The maximum WA content, about 130 mg/g, was obtained at 900 °C for 24 h. The loss of water during the expansion process in the Ugandan vermiculite caused loss of structural order and crystallinity. Moreover, in the samples expanded and subsequently immersed in water, the structural order and crystallinity increased with increasing WA values. Specific surface area and porosity hardly vary with temperature and are practically independent of vermiculite purity. Expanded commercial vermiculites could be a suitable hygroscopic material, given its efficient water absorption. Microwave expanded commercial vermiculites, in this case, would not be recommended

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Section: Discussioncontrasting

confidence: 57%

Section: Discussionmentioning

confidence: 77%

Section: Methodsmentioning

confidence: 99%

“…The other effective way is to improve energy efficiency, which can be realized through the use of thermal insulating materials with high performance [2].…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Effect of Water Immersion on Raw and Expanded Ugandan Vermiculite

Marcos

2021

Minerals

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Advances in Nanoclay‐Based Form Stable Phase Change Materials: A Review

Zhao

Zuo

Yang

2023

Adv Materials Technologies

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As the core material of thermal energy storage technology, phase change materials (PCM) suffer serious leakage problems and slow thermal conductivity in applications. Nanoclay with relatively high specific surface area, high thermal conductivity, and abundant pore structure can successfully compensate for the defects in PCM. However, the ability of nanoclay without further modification to encapsulate the PCM for the preparation of form stable phase change materials (FSPCM) and accelerate their heat transfer is limited. Nanoclay is classified into 1D, 2D, and 3D minerals based on their microscopic morphology. In this review, the specific surface and pore structure of three types of nanoclay and their thermal performance after loading with PCM are summarized and compared. Then, different mineral modification treatments, such as pretreatment, surface modification, structural modulation, and functional assembly, are summarized to investigate the enhancement of thermal performance in nanoclay‐based FSPCM. This review also summarizes the state‐of‐the‐art research progress of emerging nanoclay material‐based FSPCM. Finally, a summary of the traditional applications of mineral‐based FSPCM and an outlook on new applications are presented. This paper will help researchers to better understand the recent developments, performance enhancement strategies of nanoclay‐based FSPCM and to identify potential future research efforts.

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Fabrication, sound absorption simulation and performance optimization of multi‐layer gradient fiber‐based composites

Chen

Zhu

et al. 2023

Polymer Composites

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Noise reduction with materials of finite thickness has been a hot research topic. In this study, multi‐layer gradient fiber‐based composites integrating porous, resonant and damping structures were prepared for efficient sound absorption. Here, the effects of composite structure, fiber‐based thickness and micro‐perforated membrane fabric (MPMF) structure on the sound absorption of the composites were investigated. From the results, the sound absorption band of the composite can be effectively tuned by adjusting the structure of the MPMF or the thickness of the fiber‐based. In addition, the established acoustic model can accurately predict the sound absorption performance of the structure. It is worth mentioning that the gradient structure optimized by the algorithm exhibits broadband sound absorption (noise reduction coefficient of 0.42) and thin feature (thickness of 0.9 cm). Moreover, the medium and low frequency sound waves can be propagated and absorbed more easily by optimizing the structure of the composite. This work provides a reference for the preparation of multi‐layer gradient sound‐absorbing structures and the design of acoustic products in a specific frequency range.

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Heating temperature effect on the hygroscopicity of expanded vermiculite

Cited by 17 publications

References 20 publications

Effect of Water Immersion on Raw and Expanded Ugandan Vermiculite

Effect of Water Immersion on Raw and Expanded Ugandan Vermiculite

Advances in Nanoclay‐Based Form Stable Phase Change Materials: A Review

Fabrication, sound absorption simulation and performance optimization of multi‐layer gradient fiber‐based composites

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