Thermal study of vermiculites and mica-vermiculite interstratifications

Justo, A.; Pérez-Rodríguez, J. L.; Soto, Pedro J. Sánchez

doi:10.1007/bf02546555

Cited by 22 publications

(11 citation statements)

References 4 publications

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“…The total weight loss of this sample was 19.02%, in agreement with that reported in Table 1 and characteristic values reported for other Mg-vermiculite sampies (Justo et al 1989;Suquet et al 1991;Justo et al 1993).…”

Section: Thermogravimetric-derivative Thermogravimetric (Tg-dtg) Analsupporting

confidence: 91%

“…The 1st loss is associated in part with interlayer water of the interstratified phase produced by the treatment, and in part with interlayer water from vermiculite (Justo et al 1989;Suquet et al 1991;Justo et al 1993), whereas the 2nd and 3rd losses are assumed to correspond to different water losses originating from dehydroxylation of the interstratified phases, which need lower temperatures to reach a complete elimination. The original Mg-vermiculite layers are being altered, producing an evolution to ammonium intercalated ions.…”

Section: Thermogravimetric-derivative Thermogravimetric (Tg-dtg) Analmentioning

confidence: 99%

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Interaction of Vermiculite with Aliphatic Amides (Formamide, Acetamide and Propionamide): Formation and Study of Interstratified Phases in the Transformation of Mg- to NH₄-Vermiculite

Ruíz-Conde

1997

Clays and clay miner.

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Abstract--The Mg-vermiculite from Santa Olalla has been treated with aliphatic amides--formamide (FM), acetamide (AM) and propionamide (PM)--in aqueous solution. These treatments produce the transformation towards NH4-vermiculite and interstratified NH:vermiculite-Mg-vermiculite phases. The NH 4-vermiculite, Mg-vermiculite and interstratified (mixed-layer)~phases have been identifed from basal X-ray diffraction (XRD) interval peaks between 10,3 _~ and 14,4 A, and confirmed by direct Fourier transform method, as well as by atomic absorption spectrometry (AAS), infrared (IR) spectroscopy and thermal analysis.According to their NH:vermiculite/Mg-vermiculite probability coefficients ratio (Pa/PB), and PAA, these interstratified phases can be divided into 3 categories: 1) If the Pa/Pn ratio is --> 7/3 and PAA ~" 0,7, there are interstratified phases with a strong tendency toward segregation (case of FM, AM and PM). Experimental evidence reported in the present work indicates that the mechanism of interaction of Mg-vermiculite with FM, AM and PM in an aqueous medium takes place by ion exchange of NH 4 between the layers. The hydrolysis of these aliphatic amides leads to the liberation of NHa + into the medium. It has been found that the NH4 § sorption depends on the physico-chemical characteristics of the particular aliphatic amide, and the transformation of Mg-vermiculite to interstratified and/or NH4-vermiculite phases depends on the amide concentration. These treatments allow one to control the formation of interstratified and NH4-vermiculite phases.

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Section: Thermogravimetric-derivative Thermogravimetric (Tg-dtg) Analsupporting

confidence: 91%

Section: Thermogravimetric-derivative Thermogravimetric (Tg-dtg) Analmentioning

confidence: 99%

Interaction of Vermiculite with Aliphatic Amides (Formamide, Acetamide and Propionamide): Formation and Study of Interstratified Phases in the Transformation of Mg- to NH₄-Vermiculite

Ruíz-Conde

1997

Clays and clay miner.

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“…The waterbonding energy in the interlayer space of Mg-vermiculites mainly depends on the interlayer cation and shows similar DTA curves despite differences in the chemical composition of the tetrahedral and octahedral sheets (Justo et al, 1993).…”

Section: +2mentioning

confidence: 90%

Hydration properties of synthetic high-charge micas saturated with different cations: An experimental approach

Pavón

Castro

Naranjo

et al. 2013

American Mineralogist

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An understanding of the interaction mechanisms between exchangeable cations and layered silicates is of interest from both a basic and an applied point of view. Among 2:1 phyllosilicates, a new family of swelling high-charge synthetic micas has been shown to be potentially useful as decontaminant. However, the location of the interlayer cations, their acidity and the water structure in the interlayer space of these silicates are still unknown. The aim of this paper was therefore to study the hydration state of the interlayer cations in the interlayer space of high-charge expandable micas and to evaluate the effect that this hydration has on the swelling and acidity behavior of these new materials. To achieve these objectives, three synthetic micas with different with different charge density total layer charges (ranging between 2 and 4 per unit cell) and with five interlayer cations (Na

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“…Unlike the potassium cations in biotite, the hydrated interlayer ions (usually magnesium) in vermiculites are easily exchanged (Newman, 1987). Justo et al (1993), Ou and Bablouzian (1994) and Marcos et al (2008) have shown that, compared to pure vermiculite, mica interstratified materials feature higher expansion ratios with the thermal exfoliation also commencing at lower temperatures. The conventional processes for the manufacture of exfoliated vermiculite employs temperatures exceeding 800 °C.…”

Section: +mentioning

confidence: 99%

Thermal properties of sodium-exchanged palabora vermiculite

Muiambo

Focke

Atanasova

et al. 2010

Applied Clay Science

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Palabora represents an interstratified vermiculite-biotite containing less than 50% vermiculite. The sodium-exchanged form was prepared by immersion in saturated brine at ambient conditions. The sodium content reached the equilibrium level within the first month of exposure. However, XRD spectra continued to evolve and sharpen over a six month period. The thermal-activated exfoliation was studied using thermo-mechanical analysis. The expansion of the neat "vermiculite" commenced at temperatures above 420 C. In some applications a lower exfoliation temperature is desirable, i.e. in the range 200 to 350°C. This study revealed that simple sodium exchange is effective towards this goal as it lowered the onset temperature by about 120 C. The linear expansion reached a maximum of about eight-fold at temperatures around 700 C and decreased again at higher temperatures.

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Thermal study of vermiculites and mica-vermiculite interstratifications

Cited by 22 publications

References 4 publications

Interaction of Vermiculite with Aliphatic Amides (Formamide, Acetamide and Propionamide): Formation and Study of Interstratified Phases in the Transformation of Mg- to NH₄-Vermiculite

Interaction of Vermiculite with Aliphatic Amides (Formamide, Acetamide and Propionamide): Formation and Study of Interstratified Phases in the Transformation of Mg- to NH₄-Vermiculite

Hydration properties of synthetic high-charge micas saturated with different cations: An experimental approach

Thermal properties of sodium-exchanged palabora vermiculite

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Thermal study of vermiculites and mica-vermiculite interstratifications

Cited by 22 publications

References 4 publications

Interaction of Vermiculite with Aliphatic Amides (Formamide, Acetamide and Propionamide): Formation and Study of Interstratified Phases in the Transformation of Mg- to NH4-Vermiculite

Interaction of Vermiculite with Aliphatic Amides (Formamide, Acetamide and Propionamide): Formation and Study of Interstratified Phases in the Transformation of Mg- to NH4-Vermiculite

Hydration properties of synthetic high-charge micas saturated with different cations: An experimental approach

Thermal properties of sodium-exchanged palabora vermiculite

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Product

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Interaction of Vermiculite with Aliphatic Amides (Formamide, Acetamide and Propionamide): Formation and Study of Interstratified Phases in the Transformation of Mg- to NH₄-Vermiculite

Interaction of Vermiculite with Aliphatic Amides (Formamide, Acetamide and Propionamide): Formation and Study of Interstratified Phases in the Transformation of Mg- to NH₄-Vermiculite