Technical Details of Vermiculite

 

Technical Characteristics

Indicators

Year of discovery: 

 was first described in 1824 by mineralogist T. Webb

IMA Status: 

 Valid - first described prior to 1959 (pre-IMA) - "Grandfathered"

Origin of name: 

 the Latin word "vermiculus" ("worm", wormlike")

 

PHYSICAL PROPERTIES

Color of the mineral: 

 brown, bronze-yellow, silver

Molecular Weight: 

 504,19

Hardness (Mohse): 

 1½ - 2

Bulk density of vermiculite concentrate: 

 640-1120 kg/m3

Bulk density exfoliated vermiculite: 

 64-160 kg/m3

Specific surface: 

 6-7 m2/gr

Modulus of Elasticity: 

 1,5 - 3 kg/sec

Angle of Repose: 

 27-30 degrees

Thermal Conductivity Coefficient: 

 at 25 ° C not more than 0.06 W / m * K

 at 325 ° C not more than 0.13 W / m * K 

Fusion Point: 

 1350°С

Sintering Temperature: 

 1260°С

Application Temperature: 

 -260… +1200°С

Expansion Factor: 

 20-30

Coefficient of Thermal Expansion: 

 1,4х10-5

The sound absorption coefficient (at 1000 Hz): 

 0,7-0,8

Moisture by Weight: 

 < 5%

Water Holding Capacity: 

 400-530% of its own weight

Hygroscopicity: 

 no more than 3% by weight at 100% atmospheric humidity

 Hydrogen index pH (ISO 787-9): 

 6.8-7.0 (neutral - slightly alkaline)

Radioactivity Index (GRapi): 

 0

 

OPTICAL DATA OF VERMICULITE

Type: 

 Biaxial (-)

RI values: 

 nα = 1.525 - 1.561 nβ = 1.545 - 1.581 nγ = 1.545 - 1.581

Maximum Birefringence: 

 δ = 0.020

Surface Relief: 

 Low

Dispersion: 

 Weak

 

CRYSTALLOGRAPHY OF VERMICULITE

Crystal System: 

 Monoclinic

Cell Parameters: 

 a = 5.24Å, b = 9.17Å, c = 28.6Å,

 β = 94.6°

Ratio: 

 a:b:c = 0.571 : 1 : 3.119

Unit Cell Volume: 

 V 1,369.83 ų (Calculated from Unit Cell)

11.12.2017   12:01

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