CVG-2107 (Chapter 2) 10

CVG-2107 (Chapter 2) 10 - sandwiching a sheet of alumina....

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Prof. M. Fall - Uniersity of Ottawa Prof. M. Fall - Uniersity of Ottawa 10 4.3 Different types of clay minerals 2:1 Clay Mineral (e.g., Montmorillonite): Si Al Si Si Al Si Si Al Si 0.96 nm joined by weak van der Waal’s bond easily separated by water h also called smectite ; expands on contact with water Source Siva 4.3 Different types of clay minerals n·H 2 O+cations 5 μ m •Si 8 Al 4 O 20 (OH) 4 ·nH 2 O (Theoretical unsubstituted). Film-like shape. •n·H 2 O and cations exist between unit layers, and the basal spacing is from 9.6 Å to (after swelling). •The interlayer bonding is by van der Waals forces and by cations which balance charge deficiencies ( weak bonding ). •There exists interlayer swelling, which is very important to engineering practice ( expansive clay ). (Holtz and Kovacs, 1981) 2:1 Clay Mineral (e.g., Montmorillonite): 2:1 Minéraux d’argile (ex., Monmorollinite): 4.3 Different types of clay minerals 2:1 clays consist of two silica sheets
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Unformatted text preview: sandwiching a sheet of alumina. Water and ions easily enter between the layers which causes these clays to shrink and swell. 4.3 Different types of clay minerals h A highly reactive (expansive) clay h montmorillonite family h used as drilling mud, in slurry trench walls, stopping leaks h (OH) 4 Al 4 Si 8 O 20 .nH 2 O high affinity to water Bentonite swells on contact with water Montmorillonite 2:1 Clay Mineral 4.3 Different types of clay minerals Si Al Si Si Al Si Si Al Si 0.96 nm joined by K + ions fit into the hexagonal holes in Si-sheet 2:1 Clay Mineral (e.g., illite) iIlite Source Markley., CA Source Siva 4.3 Different types of clay minerals Different combinations of tetrahedral and octahedral sheets form different clay minerals: We can distinguish tree main groups of clay minerals 1) 1: 1 clay minerals 2) 2: 1 clay minerals 3) 2:1:1 clay minerals...
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