Crude and Exfoliated Vermiculite

Typical Specification:

Vermiculite Crude Vermiculite Exfoliated Vermiculite
No Grade Size (mm) Density (kg/m³) Density (kg/m³)
1 Large -3.0+7.0 1400-1600 140-170
2 Medium -4.0+1.4 1200-1400 130-150
3 Fine -2.0+0.7 1150-1350 120-145
4 Superfine -1.0+0.35 1100-1300 110-140

Major/Minor Components:

When analyzed chemically, crude and exfoliated vermiculite give the same values. Because vermiculite is a naturally occuring substance its exact composition may vary from sample to sample. Typical Range for Major Components

SiO Silicon Dioxide 35-41%
 Al2O3 Aluminium Oxide 6.0-9.5%
 Fe2O3 Iron Oxide 6.0-9.5%
 MgO Magnesium Oxide 21.5-25.5%
 K2O Potassium Oxide 3-6%

Typical Range for Minor Components

 CaO Calcium Oxide 2.0-6.0%
 CO2 Carbon Dioxide 0.6-2.5%
 TiO2 Titanium Dioxide 0.6-1.4%
 F Fluorine 0.2-0.8%
 Cr2O3 Chrome Oxide 0.01-0.15%
 P2O5 Phosphorus Pentoxide 0.2-2.0%
 Cl Chlorine 0-0.05%

Specific Surface Area: The specific surface area for exfoliated vermiculite, as measured by the nitrogen absorption technique, is typically –

Exfoliated Vermiculite
No Grade m2/g No Name m2/g
5 X-Large 3.0 0 Micron 6.4
4 Large 3.4 -1 Micra 6.8
3 Medium 4.0 -2 RSU 7.2
2 Fine 4.4 -3 DDM 7.5
1 Supreme 5.4      

Absorption Capacity: All grades of exfoliated vermiculite will retain liquids within the inter-laminar voids of the individual particles as well as between the particles themselves.