Über die Thixotropie von Bentonit-Suspensionen

Freundlich, H.; Schmidt, O.; Lindau, G.

doi:10.1007/bf02556246

Cited by 30 publications

(2 citation statements)

References 10 publications

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“…values of the temperature coefficient, i.e., the ratio of the rates of change for temperatures 10°C. apart are compared in table 5 with the value which might be expected for aqueous bentonite suspensions. The constants a in equation 2 for the falling-ball method were used.…”

Section: Discussionmentioning

confidence: 99%

The Gelation of Bentonite Suspensions.

Broughton¹,

Squires²

1936

J. Phys. Chem.

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It has been known for some years that certain sols, on standing, form gels which can be reliquefied by shaking. This phenomenon was first discovered by Schalek and Szegvary (13) in 1923 for ferric oxide sols to which a small amount of electrolyte, for example, sodium chloride, had been added. Since then many cases of this isothermal reversible sol-gel transformation, which Freundlich has termed "thixotropy," have been reported.Bentonite, a clay-like material, probably of volcanic origin and found largely in Wyoming, exhibits thixotropy to a marked degree in aqueous suspensions. Suspensions of suitable concentration will set to a gel in a few seconds, although a number of other factors materially influence this setting time. Particle size undoubtedly plays a great part, since centrifuged suspensions will give dispersions showing thixotropy down to at least a concentration of 1 per cent, whereas ordinary bentonite suspensions require a concentration of over 4 per cent.s The hydrogen-ion concentration of the suspension, as might be expected, was also found by Freundlich, Schmidt, and Lindau (5) to be of great importance. Acidwashed bentonite or electrodialyzed bentonite suspensions do not show thixotropic behavior. In this paper the effects of temperature and concentration upon gelation are described. No attempt has been made to determine the influence of pH, the hydrogen-ion concentration being kept m constant as possible. METHODS OF MEASUREMENTThe investigation of thixotropy is greatly hampered by the lack of an adequate method of measurement. The inverted-tube method first introduced by Schalek and Szegvary (14) has been most commonly used. The sol is introduced into a tube, which is stoppered or preferably sealed 1 Presented before the Thirteenth Colloid Symposium, held a t St.

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Section: Discussionmentioning

confidence: 99%

The Gelation of Bentonite Suspensions.

Broughton¹,

Squires²

1936

J. Phys. Chem.

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“…The flocculation of clay platelets has been extensively studied and a number of tentative flocculation mechanisms have been proposed. 1 Freundlich et al, 2 Hofmann et al 3 and Langmuir 4 all observed flocculation in clay-water systems. They observed both the formation of tactoids, i.e.…”

Section: Introductionmentioning

confidence: 97%

Nature of flocculation and tactoid formation in montmorillonite: the role of pH

Segad

Åkesson

Cabane

et al. 2015

Phys. Chem. Chem. Phys.

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The dissolution and swelling properties of montmorillonite at different pH have been studied, using small angle X-ray scattering (SAXS), imaging and osmotic stress methods combined with Monte Carlo simulations. The acidity of montmorillonite dispersions has been varied as well as the counterions to the net negatively charged platelets. At low pH, Na montmorillonite dissolves and among other species Al(3+) is released, hydrated, polymerized and then it replaces the counterions in the clay. This dramatically changes the microstructure of Na montmorillonite, which instead of having fully exfoliated platelets, turns into a structure of aggregated platelets, so-called tactoids. Montmorillonite dispersion still has a significant extra-lamellar swelling among the tactoids due to the presence of very small nanoplatelets.

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The Properties of Protoplasm: With Special Reference to the Influence of Enzymic Reactions

Seifriz

1947

Advances in Enzymology - And Related Areas of Molecular Biology

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Über die Thixotropie von Bentonit-Suspensionen

Cited by 30 publications

References 10 publications

The Gelation of Bentonite Suspensions.

The Gelation of Bentonite Suspensions.

Nature of flocculation and tactoid formation in montmorillonite: the role of pH

The Properties of Protoplasm: With Special Reference to the Influence of Enzymic Reactions

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