Etude du gonflement des vermiculites–ornithine en solution saline par analyse de la diffusion des rayons X aux petits angles. Méthode d'interprétation et recherche des paramètres d'ordre

Saez-Auñon, J.; Pons, C. H.; Iglesias, Juan Eugenio; Rausell-Colom, J. A.

doi:10.1107/s002188988301081x

Cited by 9 publications

(6 citation statements)

References 6 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The fact that the non m icroporous surface area is greater than the surface area of the starting vermiculite reveals that the organization of the crystals is certainly modified by the exchange procedure. This is not really surprising as it has been shown that Lornithine exchanged vermiculites swell exten sively in w ater (Saez-A unon et al, 1983). A fter calcination for 12 h at 500°C, the sample exhibits a BET surface area of 160 m2.g_1.…”

Section: Resultsmentioning

confidence: 72%

Partial Pillaring of Vermiculite by Aluminium Polycations

Michot¹,

Tracas²,

Lartiges³

et al. 1994

Clay miner.

View full text Add to dashboard Cite

Section: Resultsmentioning

confidence: 72%

Partial Pillaring of Vermiculite by Aluminium Polycations

Michot¹,

Tracas²,

Lartiges³

et al. 1994

Clay miner.

View full text Add to dashboard Cite

“…Lorsque la diffusion centrale produite par les particules rejoint sans s'annuler le domaine de Bragg correspondant fi la premiere r~flexion 001 et que le d~sordre structural au sein des particules est important, le chevauchement des lois relatives fi chacun des domaines emp~che par ces m&hodes toute interpr&ation quantitative (Pons, 1980). Dans ce cas, il est prefbrable d'utiliser la m&hode indirecte qui consiste ~t comparer la courbe d'intensit~ exp6rimentale ~ une courbe d'intensit6 th~orique obtenue ~ partir d'un module structural (Pons et aL, 1981 ;Saez et aL, 1983).…”

Section: Fixation De L'dtat Hydrique Et Protocole Expdrimentalunclassified

Comportement hydrique et évolution structurale et texturale des montmorillonites au tours d'un cycle de dessiccation-humectation: partie I. Cas des montmorillonites calciques

Benrhaiem

Tessier²,

Pons

1986

Clay miner.

View full text Add to dashboard Cite

RI~SUMt~: L'~volution structurale et texturale ainsi que le comportement hydrique de deux montmorillonites-Ca (Wyoming et grecque) ont ~t~ &udi~s par microscopic ~lectronique fi transmission (MET) et plus pr~cis~ment par analyse de la diffusion aux petits angles des rayons X (DPAX). L'~tude au MET a permis de montrer qu'/l faible contrainte, le mat~riau est form~ par un r~seau de particules d~formables d~limitant des pores de grandes dimensions (~2 #m). L'6tude en DPAX des m~mes syst~mes soumis fi une contrainte de type succion a montr~ que: 1. Lors de la premiere dessiceation il y a d'abord d~formation du r~seau sans regroupement des particules (p <~ 1 bar), puis regroupement des particules face-face pour former des particules de plus grande ~palsseur (p > 1 bar). On montre aussi que l'eau est essentiellement extraite de la porosit~ interparticulaire. 2. Lors de la r~hydratation, on met en ~vidence qu'apr~s dessiccation le syst6me perd une grande partie de son aptitude ~, reprendre de l'eau et que cette perte est d'autant plus importante que le niveau de dessiccation pr~alable a &~ ~lev6. Ceci est dO au falt qu'une partie de la porosit~ est r~duite fi des espaces ayant la propri~t~ de l'espace interfoliaire.ABSTRACT: The structural and textural changes and swelling behaviour of two Camontmor]llonites (Greek and Wyoming) were studied by TEM and small-angle XRD. When examined by TEM at low stress, the texture was a network of particles enclosing large-size pores (~ 2 #m). XRD examination of the clays under suction showed that: 1. When first dried, the network changed configuration without coalescence of the particles (p ~< 1 bar). Afterwards, the particles became bound face-to-face and formed thicker groupings (p > 1 bar). Water was also found to be derived essentially from inter-particle porosity. 2. During rehydration the desiccated system had lost, to a great extent, its ability to recover water, this loss being greater the higher the preliminary desiccation. This is due to the fact that porosity was confined in part to spaces which had the same property as the interlayer space.Au niveau de la structure des sols, il est clair que les argiles jouent un r61e sp6cifique qui n'est pas seulement dfi fi leur propri6t6, commune fi beaucoup de constituants des sols, de pouvoir capter et retenir l'eau. Le fait important est que cette prise, ou ce d6part d'eau, s'accompagne g6n6ralement d'une modification du volume apparent et qu'elle se traduit, fi diff6rentes 6chelles, par une r6organisation du mat6riau (

show abstract

“…The mechanism leading to the appearance of these properties is linked with the interlamellar swelling of clay in contact with an ionic solution (Mdring 1946;Barshad 1953;Norrish 1954;Quirk 1968;Van Olphen 1977;Pons 1980;Saez-Aunon et al 1983;Tessier 1984;Raussel-Colom et al 1989). One problem occurring during drilling is to control the swollen states and their total or partial reversibility under the action of different physicochemical parameters and different stresses to which the clay can be subjected (chargebalancing cation, salt concentration of the solution, temperature).…”

Section: Introductionmentioning

confidence: 99%

Structural Organization of Na- and K-Montmorillonite Suspensions in Response to Osmotic and Thermal Stresses

Faisandier

1998

Clays and clay miner.

View full text Add to dashboard Cite

Abstract--In order to understand the influence of salt concentration and temperature on the behavior and properties of clays used in drilling muds, we studied montmorillonite supensions (4 g clay/100 g solution) in 0.1, 0.5 and 1 M NaC1 and KC1 solutions. A fraction of each sample was heated to 200 ~ in a closed vessel for 7 d, then cooled at room temperature (RT, 25 ~ Small-angle X-ray scattering (SAXS) spectra were recorded, for all the samples, at RT. The structure of the clay particles was determined by comparing the experimental intensity with the theoretical intensity computed from a model that took into account the number of layers per particle, the hydration state of the layers (0, l, 2, 3 or 4 water layers) and the order in the succession of these states. With this set of parameters, we can compute the mean statistical parameters ~/ (mean number of layers per particle), cl (mean interlayer distance) and g2/~ (parameter describing the disorder of the distribution of interlayer distances). The evolution of these parameters shows that: 1) At low concentration (0.1 M NaC1 or KC1), the samples do not consist of particles but of isolated layers (M = 1). The suspensions form gel-like structures. The difference between Na and K suspensions, or between heated and nonheated samples, is unnoticeable at the studied scale (5-500 ,~).2) An increase in salt concentration (from 0.1 to 0.5 M) brings the sample in a granular state: we notice the appearance of particles at 0.5 M (~7/ ~ 25). Differences appear between NaC1 and KC1 suspensions, and the temperature effect becomes visible. Thus, we noticed that in NaC1 suspensions, particles are composed of hydrated layers (1, 2, 3 or 4 water layers) and internal porositYo(d > 30 A), whereas suspensions in KC1 are characterized by the presence of interlayer distances of 10 A, that is, of collapsed layers. Particles in the KC1 suspensions are much thicker than in the NaCI corresponding ones, and also less hydrated at the interlayer level as well as at the internal porosity level. Further increase in salt concentration (0.5 to 1 M) amplifies this effect. As far as temperature is concerned, its effect is to promote the clay dispersion by breaking up the particles, dehydrating and disordering them. This effect is more important for low salt concentration, that is, when the system is less stressed.

show abstract

Etude du gonflement des vermiculites–ornithine en solution saline par analyse de la diffusion des rayons X aux petits angles. Méthode d'interprétation et recherche des paramètres d'ordre

Cited by 9 publications

References 6 publications

Partial Pillaring of Vermiculite by Aluminium Polycations

Partial Pillaring of Vermiculite by Aluminium Polycations

Comportement hydrique et évolution structurale et texturale des montmorillonites au tours d'un cycle de dessiccation-humectation: partie I. Cas des montmorillonites calciques

Structural Organization of Na- and K-Montmorillonite Suspensions in Response to Osmotic and Thermal Stresses

Contact Info

Product

Resources

About