What is Perlite?
 Perlite is not a trade name but a
generic term for naturally occurring
siliceous rock. The distinguishing
feature which sets perlite apart from
other volcanic glasses is that when
heated to a suitable point in its
softening range, it expands from four to
twenty times its original volume.
This expansion is due to the presence of
two to six percent combined water in the
crude perlite rock. When quickly heated
to above 1600°F (871°C), the crude rock
pops in a manner similar to popcorn as
the combined water vaporizes and creates
countless tiny bubbles which account for
the amazing light weight and other
exceptional physical properties of
expanded perlite
This expansion process also creates one
of perlite's most distinguishing
characteristics: its white color. While
the crude rock may range from
transparent light gray to glossy black,
the color of expanded perlite ranges
from snowy white to grayish white.
Expanded perlite can be manufactured to
weigh as little as 2 pounds per cubic
foot making it adaptable for numerous
applications.
Since perlite is a form of natural
glass, it is classified as chemically
inert and has a PH of approximately 7.
Perlite is mined and expanded all over
the world. Iran is estimated to be the
largest producer of crude and expanded
perlite. However, there is very strong
world wide production and consumption of
perlite.
Perlite Physical Properties
| G.E. Brightness |
50-85% |
| Refractive Index |
1.47 |
| Color |
White |
| Oil adsorption, gms oil/gm |
50-100 |
| Hardness Handle ability |
Good |
| Hardness Ignition Loss, (1 hour at 1800F) |
2.0% max |
| Specific Gravity |
2.34 |
| Moisture,% |
<1 |
| Water adsorption, % weight |
200-600 |
| Flow ability |
Good |
| Absorption rate |
Instantaneous |
Main Properties of Perlite
Expands when heated: Crushed perlite has the property of
expanding when heated at varying
temperatures between 900o to 1100o C.
Its volume may increase four- to twenty-fold.
Perlite Porous Texture
Surface pores or cavities develop on
perlite particles during dilation. These
pores trap moisture on which plant roots
thrive. Perlite particles are irregular
in shape and leave air passages in the
soil at the base of plant cultures, for optimal aeration.
Perlite Liquid Retention
Perlite’s porous texture retains moisture and fertilizers. With appropriate granule size, perlite
provides optimal irrigation as well as perfect drainage for all your horticultural projects.
Air Circulation
Because of their irregular shape,
perlite particles provide aeration in
growing mixes and substrates, and in
many industrial applications.
Low Density – Can't Be Compacted
Since heated perlite increases in volume
while keeping the same mass, expanded
perlite has a very law density which,
combined with its other characteristics
(neutral pH and porous texture), makes
it an ideal filling material which
cannot be further compacted.
Chemically Neutral
Perlite is an odorless, non-flammable,
and non-explosive chemical; an inorganic
component which does not deteriorate.
Other benefits of horticultural perlite
are its neutral pH (6.5 to 7.5) and the
fact that it is sterile and weed-free.
These reasons explain its popularity for
various applications from window boxes
to filtration in pharmaceutical and food industries.
Low Conductivity – Insulation, Fireproofing and Soundproofing:
Perlite’s law conductivity makes it an
ideal refractory material in bricks or
tiles or as insulating material in pipes
Perlite Uses
There are many uses for perlite. These
uses can be broken down into three
general categories: construction
applications, horticultural
applications, and industrial applications
Construction Applications
Because of perlite's outstanding
insulating characteristics and light
weight, it is widely used as loose-fill
insulation in masonry construction. In
this application, free-flowing perlite
loose-fill masonry insulation is poured
into the cavities of concrete block
where it completely fills all cores,
crevices, mortar areas and ear holes. In
addition to providing thermal
insulation, perlite enhances fire
ratings, reduces noise transmission and
it is rot, vermin and termite resistant.
Perlite is also ideal for insulating law
temperature and cryogenic vessels. When
perlite is used as an aggregate in
concrete, a lightweight, fire resistant,
insulating concrete is produced that is
ideal for roof decks and other
applications. Perlite can also be used
as an aggregate in Portland cement and
gypsum plasters for exterior
applications and for the fire protection
of beams and columns. Other construction
applications include under-floor
insulation, chimney linings, paint
texturing, gypsum boards, ceiling tiles,
and roof insulation boards.
Horticultural Applications
In horticultural applications, perlite
is used throughout the world as a
component of soil less growing mixes
where it provides aeration and optimum
moisture retention for superior plant
growth. For rooting cuttings, 100%
perlite is used. Studies have shown that
outstanding yields are achieved with
perlite hydroponics systems. Other
benefits of horticultural perlite are
its neutral PH and the fact that it is
sterile and weed-free. In addition, its
light weight makes it ideal for use in
container growing. Other horticultural
applications for perlite are as a
carrier for fertilizer, herbicides and
pesticides and for pelletizing seed.
Horticultural perlite is useful to the
home gardener as it is to the commercial
grower. It is used with equal success in
greenhouse growing, landscaping
applications and in the home in house plants.
Perlite Industrial Applications
Industrial applications for perlite are
the most diverse, ranging from high
performance fillers for plastics to
cement for petroleum, water and
geothermal wells. Other applications
include its use as a filter media for
pharmaceuticals, food products,
chemicals and water for municipal systems and swimming pools.
Additional applications include its use
as an abrasive in soaps, cleaners, and
polishes; and a variety of foundry
applications utilizing perlite's
insulating properties and high heat
resistance. This same heat resistant
property is taken advantage of when
perlite is used in the manufacture of
refractory bricks, mortars, and pipe insulation.
Recommended Filled of Application
| Kind of powder |
Talc |
Mica |
Kaolin |
Red Iron oxide |
Fluorine |
Dolomite |
Calcite |
Bentonite |
Barite |
| Ceramics |
• |
|
• |
• |
• |
• |
• |
• |
• |
| Chinaware |
• |
|
• |
|
|
|
|
|
|
| Excavation |
|
• |
|
|
|
• |
• |
• |
• |
| Elecrode |
• |
• |
|
|
• |
• |
• |
|
• |
| Feed |
|
|
|
|
|
|
• |
• |
|
| Glass |
• |
|
|
|
• |
• |
• |
|
• |
| Glaze |
|
|
• |
|
• |
• |
|
• |
|
| Glue |
• |
|
• |
|
|
|
• |
|
|
| Gerannlation (p.v.c) |
|
|
|
|
|
|
• |
|
|
| Insecticide |
• |
|
• |
|
|
|
|
• |
• |
| Isolation |
• |
|
|
|
|
|
• |
|
|
| lining |
|
|
|
|
|
• |
• |
|
• |
| Paint |
• |
• |
• |
• |
|
|
• |
• |
• |
| Pharmaceutical |
• |
|
• |
|
|
|
• |
• |
• |
| Plastic |
• |
|
• |
|
|
|
• |
|
• |
| Rulp & paper |
• |
|
|
|
|
|
• |
• |
• |
| Rubber |
• |
• |
• |
|
|
|
• |
|
• |
| Textile |
• |
|
|
|
|
|
• |
|
• |
|