Results 191 to 200 of about 4,204 (206)

Nature of dioctahedral micas in Spanish red soils

Clay Minerals, 1997
AbstractStructural formulae and other crystallochemical parameters were used to study different species of dioctahedral micas in clay and coarse gravel fractions of horizons from a red soil (Ultic Haploxeralf) in southern Spain. Mineralogical analyses using X-ray powder diffraction, and measurements of theb0parameter revealed dioctahedral micas, illite
J. M. Martin-Garcia, G. Delgado, M. Sanchez-Maranon, J. F. Parraga, R. Delgado   +4 more
openaire   +1 more source

Tetrahedral charge and Fe content in dioctahedral smectites

Clay Minerals, 2017
AbstractNatural aluminosilicates can contain Fe in tetrahedral or octahedral coordination. Amongst smectites, tetrahedral iron is known to occur in Fe-rich nontronites but few indications exist for the presence of tetrahedral Fe in smectites of the montmorillonite–beidellite series.
Kaufhold, S., Stucki, J. W., Finck, N., Steininger, R., Zimina, A., Dohrmann, R., Ufer, K., Pentrák, M., Pentráková, L.   +8 more
openaire   +2 more sources

Interstratification of trioctahedral and dioctahedral smectites through delamination and costacking

Journal of Colloid and Interface Science, 2008
Trioctahedral and dioctahedral organosmectites delaminate in 1-octanol to give stable monolayer colloidal dispersions. Addition of acetone to a mixture of these colloidal dispersions yields a composite of the two clays. Layers of the two smectites are interstratified in the composite.
Venugopal, BR, Ravishankar, N, Rajamathi, Michael   +2 more
openaire   +2 more sources

Structural Factors Controlling Stacking Sequences in Dioctahedral Micas

Clays and Clay Minerals, 1971
AbstractDeviations in the symmetry of mica single layers from the ideal arrangement with all atoms in hexagonal arrays are caused by the structural factors such as compositional variation (substitutions), order-disorder, and distortions. The derivative crystal structure theory as applied to mica polymorphism, implies that the ideal symmetry of the mica
openaire   +1 more source

Synthesis and characterisation of dioctahedral smectites.

2004
The synthetic clays are used in a lot of studies to analyse clay properties. They permit to have samples without impurities and with a specific chemical composition. In synthetic smectite group, trioctahedral smectites as saponite were generally studied.
Lantenois, Sébastien, Muller, Fabrice, Champallier, Rémi, Bény, Jean-Michel   +3 more
openaire   +1 more source

Crystal-chemical microheterogeneity of Precambrian globular dioctahedral mica minerals

Lithology and Mineral Resources, 2013
The paper presents a novel method for determining the crystal-chemical heterogeneity of finely dispersed dioctahedral 2: 1 mica mineral phases based on the modeling of their powder diffraction patterns. We used three samples, which were taken from Lower-Middle Riphean rock sections of the Anabar and Olenek uplifts in northern Siberia, and one sample ...
V. A. Drits, B. A. Sakharov, T. A. Ivanovskaya, E. V. Pokrovskaya   +3 more
openaire   +1 more source

Catalytic Properties of a Heated Ammonium-Saturated Dioctahedral Smectite

Collection of Czechoslovak Chemical Communications, 2000
A series of acid catalysts was prepared by heating of NH4-saturated montmorillonite at 200-600 °C for 24 h. Their catalytic activity was tested in acetylation of 3,4,5-trimethoxybenzaldehyde with acetic anhydride. This reaction is sufficiently sensitive to modification of the catalyst and thus suitable for testing catalytic activity of modified ...
Ľuboš Jankovič, Peter Komadel
openaire   +1 more source

Infrared Evidence of Dioctahedral-Trioctahedral Site Occupancy in Palygorskite

Clays and Clay Minerals, 2002
AbstractA Mg-rich palygorskite sample from phosphorite deposits of Ganntour (Morocco) with the structural formula Si8(Mg2.6Al1.19Fe0.33III□0.88)Ca0.056Na0.024K0.104O20(OH)2(OH2)4⋅4H2O, was studied by FTIR spectroscopy. In both OH-stretching and OH-bending regions, there is evidence of dioctahedral Al2□OH, AlFe□OH and trioctahedral Mg3OH features ...
A. Chahi, S. Petit, A. Decarreau
openaire   +1 more source

CONCENTRATION OF DIOCTAHEDRAL MICA AND VERMICULITE USING A FLUORIDE SOLUTION

Clays and Clay Minerals, 1966
AbstractA Solution containing fluoride (0.4 n NH4F, 0.1 n HCl, n NH4Cl), permits the concentration of dioctahedral mica and dioctahedral vermiculite in mixed clay systems. Allophane, halloysite, kaolinite, and in particular, Mg-rich montmorillonite, biotite, and vermiculite of clay size, are destroyed in 24–48 hr at room temperature.
openaire   +1 more source

Insights on Adsorptive Property of Thermally Treated Smectite (Dioctahedral)

Surface and Interface Analysis
ABSTRACT The use of clay in the field of mineral materials is directly impacted by its thermal stability and changes in microstructure and properties following heat and other treatments. Therefore, it is crucial to investigate how clay's composition and structure are changed with time or how its surface characteristics are changed ...
Qaisar Abbas Bhatti, Azia Mouzam, Muhammad Ishaq, Noor‐Ul‐Saba Javid, Amna Tariq, Musa Kaleem Baloch   +5 more
openaire   +1 more source