Fabric of Kaolinite and Illite Floccules

Abstract

Abstraet-A scanning and high voltage electron microscope study of the fabric of laboratory sedimented moist uncompressed kaolinite and illite floccules reveals an abundance of face-face flake orientation in the porous clay network. Clays were flocculated in the laboratory in both distilled water and slightly saline (1 g/l. NaCI) water using various clay concentrations. Floccules taken from the moist clay mass were prepared for study by freeze-drying and impregnation with polyethylene glycol.There is little difference in the fabric of kaolinite flocculated in distilled or slightly saline water. The fabric is dominated by a 3-dimensional network of twisted chains of face-face oriented flakes having the appearance of a stair-stepped cardhouse. Illite floccules in distilled water also consist of abundant face-face oriented overlapping flakes. However, in salt water there is a more even mixture of fabrics-edge-to-face flooculation of individual platelets and also stepped clusters of face-to-face oriented flakes, the latter being more abundant.It is suggested that under the experimental conditions the double layer of each clay panicle is compressed resulting in an increase in the importance of van der Waals forces of attraction. As a result flakes approach each other and rotate into a parallel or subparallel position. The resultant dominant fabric is that of a stepped cluster of overlapping flakes.

Influence of Calcium and Sodium Concentration on the Microstructure of Bentonite and Kaolin

“…Here, stairstep structures were noted inside of microaggregates, probably because of the partial translocation of kaolinite platelets in relation to one another. O'Brien (1971) proved the existence of this type of kaolinite aggregate. A tenfold increase of the sodium salt concentration (Figure 8.3) led to the formation of larger plates, because of the increase in F-F interactions.…”

“…Small aliquots of the sedimented deposits were rapidly frozen in liquid nitrogen to fix the microstructure (O'Brien, 1971). The frozen samples were freeze dried at -30~ and 0.1 Pa for 24 hr.…”

The Rheological and Colloidal Properties of Bentonite Dispersions in the Presence of Organic Compounds V. Bentonite and Sodium Montmorillonite and Surfactants

“…Figure 4 in Permien and Lagaly 1994a) (Norrish 1954, Callaghan and Ottewill 1974, Rand et al 1980, Permien and Lagaly 1994a. Another consequence of the extreme aspect ratio of the delaminated particles is the preferential face-toface aggregation and formation of band-type networks (Weiss and Frank 1961, Weiss 1962, Fitzsimmons et al 1970, O'Brien 1971, Fukushima 1984, Keren et al 1988, Keren 1989, Quirk 1986, Quirk and Murray 1991, Ramsay and Lindner 1993, Permien and Lagaly 1994a, 1994b. Card-house structures are less important in montmorillonite than in kaolinite dispersions because the positive charging of the montmorillonite edges only occurs in strongly acidic milieu Lagaly 1994c, 1994d).…”

Transmission X-ray Microscopy—A New Tool in Clay Mineral Floccules Characterization

“…Rosenquist [1] published a micrograph confirming the existence of the -card house‖ structure. Bowles [2] and O'Brien [3] confirmed the presence of the honeycomb microstructure in wet clay sediments. Grabowska-Olszewska [4] using cryo-SEM investigations published a large amount of microstructural data from 86 studied samples of wet clay rocks combined with compositional and physical properties.…”