Large Grade A4 South African Vermiculite

4 mm to 8 mm

J.P. Austin / A-Tops Vermiculite A - 4  


J.P. Austin / A-Tops Vermiculite Grade A  4 is a premium, large particle size material meeting ASTM C516 Type 1, Grade 1 specifications.  The material is ideally suited for use as high temperature insulation.  Another primary use is packaging of hazardous chemicals for air transport in accordance with IATA Regulations.



Product Information


Vermiculite is the geological name given to a group of hydrated, laminar minerals which are aluminum-iron-magnesium silicates, resembling mica in appearance.  When exposed to intense heat, the material expands or exfoliates. 


Exfoliated vermiculite has several unique properties which have industrial applications and account for its commercial value.  These properties include, low thermal conductivity, high water holding capacity, incombustibility, and insolubility in both water and organic solvents.                  

Physical Properties


Typical Sieve Analysis:

Unit Weight    4.0  5.5 lb/cf
pH in Water    6  9
Moisture loss @ 230°F4  10% 
Sintering Temp.  2100 - 2280°

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