Clay and Clay Minerals:

Hectorite

Festkörperpraktikum

Modul AC III 2014

What is Clay? : (Ton)

•Designation of the smallest particle size fraction of soil

(irrespective of the mineral composition)

•Mineral name for natural, earthy, fine-grained material

Main component: clay minerals (layered silicates)

Structure of the layered silicates

• 2D Structure (layered structure)

• anisotropic particles

• nanocrystalline

a) Brucite type octahedral (trioctahedral;CdI2-Typ; Brucite: Mg(OH)2)

b) Tetrahedral layer

c) Gibbsite type octahedral (dioctahedral; BiI3-Typ Gibbsite: Al(OH)3)

a b c

Hectorite

Saponite

Vermiculite

y)x(

210

.

4

.

yy3

.

2

n

nx (F)OSi LiMg OHZ

TetOktZwi

z)x(

210

.

z4z

.

3

.

2

n

nx (F)OSiAl Mg OHZ

TetOktZwi

y)zx(

210

.

z4z

.

yy3

.

2

n

nx (F)OSiAl AlMg OHZ

TetOktZwi

Structure of the layered silicates

Classification of layered silicates

Morphology of layered silicates

Importance for Humanity

Effect of weather

(e.g layered silicate)

everywhere

•Soil (30-40%)

•Mud

•Sediments

2D Structure

anisotropic particles

nanocrystalline

Special Material Properties

Plasticity

Thixotropy

Ad- and Absorption

Cation Exchange •Agriculture

•Construction

•Industry

source properties

Reactivity of the edge

Thixotropic structures by house of cards

Applications

• Thixotropic additives :

Colors,

Drilling emulsions ...

• Adsorbents :

Cat Litter ,

Packaging...

• Carrier materials

• Additives for composite materials

Construction materials,

Reactions in the interlayer space

Analysis - Powder Diffraction

d [001] = 2·d [002] = 3·d [003] = l·d [00l]

Integrity of the series:

X

SD100CV

CV: Coefficient of Variation

CV > 0,75 %: random inter

stratified

(different d-spacing along

stacking)

CV < 0,75 %: ordered system

(ordered stacking sequence)

Analysis - Powder Diffraction

As Fe-bipy-hectorite with Na-hectorite

Fe-bipy hectorite d001 at about 1.8 nm,

the Na-hectorite-d001 is about 1.2 nm

The 001 reflection is usually the strongest reflection and largest d value

Viel Erfolg!