Thermal analysis of selected illite and smectite clay minerals. Part I. Illite clay specimens

Earnest, Charles M.

doi:10.1007/bfb0010271

Cited by 16 publications

(14 citation statements)

References 7 publications

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“…At 1000 o C there is a marked change in the spectrum with the AlO 6 resonance appears at 14.9 ppm which increases in intensity on heating up to 1600 o C.…”

Section: Resultsmentioning

confidence: 99%

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Solid-state NMR characterisation of the thermal transformation of a Hungarian white illite

Carroll

Kemp

Bastow

et al. 2005

Solid State Nuclear Magnetic Resonance

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Abstract1 H, 27 Al, 29 Si and 39 K solid state NMR are reported from a Hungarian illite 2:1 clay for samples heated up 1600 o C. This single phase sample has a small amount of aluminium substitution in the silica layer and very low iron-content (~0.4 wt%). Thermal analysis shows several events that can be related to features in the NMR spectra, and hence changes in the atomic scale structure. As dehydroxylation occurs there is increasing AlO 4 and AlO 5 -contents. The silica and gibbsite layers become increasingly separated as the dehydroxylation progresses. Between 900 and 1000 o C the silica layer forms a potassium aluminosilicate glass. The gibbsite-layer forms spinel/γ-Al 2 O 3 and some aluminium-rich mullite. Then on heating to 1600 o C changes in the 29 Si and 27 Al MAS NMR spectra are consistent with the aluminosilicate glass increasing its aluminium-content, the amount of mullite increasing probably with its silicon-content also increasing, and some α-Al 2 O 3 forming.

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“…At 1000 o C there is a marked change in the spectrum with the AlO 6 resonance appears at 14.9 ppm which increases in intensity on heating up to 1600 o C.…”

Section: Resultsmentioning

confidence: 99%

“…Earlier studies on illite-rich clays [6][7][8][9] using various techniques such as ESR and Mössbauer show there are four main reaction processes which occur; viz. dehydration, dehydroxylation, structural breakdown and re-crystallisation.…”

Section: Introductionmentioning

confidence: 99%

Solid-state NMR characterisation of the thermal transformation of a Hungarian white illite

Carroll

Kemp

Bastow

et al. 2005

Solid State Nuclear Magnetic Resonance

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“…The dehydroxylation of Ilt occurs at a higher temperature (709°C). The broad DTG peak at approximately 800-900°C corresponds to the matrix destruction of the silicate lattice [27].…”

Section: Thermal Analysismentioning

confidence: 99%

Effects of solid acidity of clay minerals on the thermal decomposition of 12-aminolauric acid

Liu

Yuan

Dong

et al. 2013

J Therm Anal Calorim

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In this study, the effects of four types of clay minerals on the thermal decomposition of 12-aminolauric acid (ALA) were investigated. The decomposition temperature of ALA in ALA-clay complexes was in the range of 200-500°C. The derivative thermogravimetry results indicated that all clay minerals exhibited catalytic activity on the decomposition of ALA. Pure ALA decomposed at approximately 464°C, a temperature higher than the decomposition temperature of ALA in the presence of clay minerals. The decomposition temperature of ALA in different ALA-clay complexes follows the order illite (452°C) [ kaolinite (419°C) [ rectorite (417°C) [ montmorillonite (400°C). This order is negatively correlated with the amounts of solid acid sites in the clay minerals, indicating that ALA is catalyzed by the solid acid sites in these minerals.

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“…The term "illite" was proposed by the geologists R. E. Grim and W. E Bradley (Grim and Bradley 1940) as a general term given to a mixture of minerals including muscovite and feldspar (Deer et al 1992) whose physical properties resemble those of the mica family. They have no expanding lattice characteristics (Earnest 1991) and thus are low in water absorbency. It has been generally accepted that the main difference between mica and illite is that micas contain more K as interlayer cations, whereas illite contains more water and silica.…”

Section: Introductionmentioning

confidence: 99%

“…Earlier studies of illite-rich clays (Grim and Bradley 1940;Michael and McWhinnie 1989;Earnest 1991;Deer et al 1992; Murad and Wagner 1996) using var- ious techniques such as electron spin resonance (ESR) and M6ssbauer show there are 4 main reaction processes that occur on calcination: dehydration, dehydroxylation, structural breakdown and recrystallization. Interlayer water is driven off by 350-400 ~ followed by dehydroxylation between 450-700 ~ and irreversible structural breakdown between 800-900 ~ The formation of spinel occurs at 900 ~ and continues to increase in amount and particle size with increasing temperature.…”

Section: Introductionmentioning

confidence: 99%

Solid State NMR Characterization of the Thermal Transformation of an Illite-Rich Clay

Roch

1998

Clays and clay miner.

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Abstract--Lode, a dioctahedral illite-rich clay from Latvia belonging to the mica group of clay minerals, undergoes thermal transformation via a series of structurally disordered intermediate phases. Despite containing high levels of paramagnetic Fe substituted into the octahedral sites, 29Si and 27A1 magic angle spinning nuclear magnetic resonance (MAS NMR) spectra of sufficient quality are obtained to resolve different structural units, showing clearly defined structural changes which occur in the sample during calcination to 1200 ~ However, Fe plays a significant role in broadening the A1 signal, with integrated peak intensities decreasing as temperature increases. Significant differences are revealed in the thermal decomposition process by NMR spectra between pyrophyllite, Ca-montmorillonite and illite clays, possibly due to the different cations present in the interlayer. It has also been shown for illite that no structural differences at the atomic level occur when the dwell time at a particular temperature is varied and no difference is observed between samples that have different thermal histories; however, a minor effect of particle size and surface area is visible in the NMR data.

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Thermal analysis of selected illite and smectite clay minerals. Part I. Illite clay specimens

Cited by 16 publications

References 7 publications

Solid-state NMR characterisation of the thermal transformation of a Hungarian white illite

Solid-state NMR characterisation of the thermal transformation of a Hungarian white illite

Effects of solid acidity of clay minerals on the thermal decomposition of 12-aminolauric acid

Solid State NMR Characterization of the Thermal Transformation of an Illite-Rich Clay

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