R. F. Giese Geology glgclay@acsu.buffalo.edu Clays as Colloids R. F. Giese Geology glgclay@acsu.buffalo.edu
Meaning of “clay” Engineering Geological small particles of any material Geological small particles of layer silicate minerals 2/26/02
Outline Uses. Structure. Chemistry. Surface properties. Stability of clay-water systems Landslide 2/26/02
Importance of clays Industrial Geological thickeners (paints, drilling muds) catalysts (cracking of hydrocarbons) fillers (rubber, plastics) adsorbents Geological alteration products of rock formation of hydrocarbons 2/26/02
Importance of clays Scientific large surface area known surface structure nano-composites insulators designer surfaces 2/26/02
Clay Minerals Layer silicates Silicates are oxides of silicon and other elements: Aluminum, magnesium, iron, calcium, sodium Oxygen (anion) is larger than the other elements (cations) 2/26/02
2/26/02
2/26/02
2/26/02
2/26/02
2/26/02
2/26/02
2/26/02
2/26/02
2/26/02
Origin and calculation of the layer charge for 2:1 clay minerals. 2/26/02
Kaolinite: TEM replica 2/26/02
Kaolinite: TEM 2/26/02
Halloysite: TEM 2/26/02
2/26/02
Micas 2/26/02
Smectites Vermiculites 2/26/02
Organo-clays 2/26/02
2/26/02
2/26/02
Montmorillonite: TEM replica 2/26/02
Montmorillonite: TEM 2/26/02
Allophane TEM replica 2/26/02
Allophane TEM replica 2/26/02
Surface tension measurements Single crystals (micas) oriented films (smectites) thin layer wicking (kaolinite) 2/26/02
Generalities for clays 2/26/02
difference between hydrophobic and hydrophilic For all natural clays: difference between hydrophobic and hydrophilic 2/26/02
Natural and modified clay materials 2/26/02
Coverage of talc by a long chain amine (in wt%) 2/26/02
Coverage of smectite by organic matter 2/26/02
2/26/02
2/26/02
Interactions in water Flocculation Adsorption DLVO versus XDLVO 2/26/02
2/26/02
Montmorillonite: XDLVO 2/26/02
Stability of montmorillonite 2/26/02
Quick clays Clays deposited in marine environment sea level drops rain leaches out the salty pore water attraction between particles is weakened soil becomes unstable Canada, Scandinavia 2/26/02