Chemrock Cryogenics UK, Ltd.

PerliteExpanded perlite

Perlite in the natural state is a dense, glassy rock formed by volcanic action, which in the raw form contains about 3 % of crystal water and has a density of about 1,050 kg/m. When rapidly heated to high temperature (1.000 C) the water vaporizes instantaneously and the crushed perlite "pops" like pop corn, expanding till 20 times its original volume. The resulting snow-white granules are composed of many tiny closed air cells or bubbles. They are very light in density, fully inert and neutral. The resultant cellular structure accounts for the lightweight and excellent thermal insulation properties. Due to the sealed nature of the cells, expanded perlite has more strength and resists penetration of water to a greater extend than open celled aggregates of the same weight.

Physical Properties

Rock structures:

 Classical perlite

Colour:

 Grey

Bulk Density:

 900 - 1100 kg/m

Moisture:

 max. 1 %

pH:

 6 - 8.5

Typical Chemical Composition Perlite

Major Elements

Typical Range in %

SiO2

72 - 75

Al2O2

11 - 14

Fe2O3

0.5 - 0.9

Na2O

2.8 - 4.3

K2O

4.8 - 5.7

CaO

0.1 - 0.8

MgO

0.10 - 0.25

H2O (L.O.I.)

3.2 - 4.3

Typical Values After Expansion

Loose Weight Density:

 35 - 45 kg/m

Tamped Weight Density:

 55 - 60 kg/m

Colour:

 White

Free Quartz:

 < 0.5 %

Mechanical Resistance:

 0.6 - 1.51 kg/cm/cm

Thermal Conductivity λs =  0.034 - 0.042 W/(m.K)
Softening point:  890 - 1100 C
Fusion point:  1280 - 1350 C
Specific heat:  0.20
Specific gravity:  2.2 - 2.4
Fire resistance:  Perlite is non-combustible

MSDS expanded perlite: