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kaolinit

Kaolinite, also written kaolinit in some languages, is a clay mineral with the chemical formula Al2Si2O5(OH)4. It is a member of the kaolinite family of phyllosilicates and forms a 1:1 layered silicate in which tetrahedral silica sheets alternate with octahedral alumina sheets. The layers are held together by hydrogen bonds, making the mineral relatively non-expandable.

Formation and occurrence: Kaolinite forms by the chemical weathering of feldspar-rich rocks under acidic conditions and

Properties: Kaolinite has a relatively low cation exchange capacity, modest hardness (about 2–3 on the Mohs

Uses and processing: The mineral is widely used in ceramics for porcelain and whiteware, and as a

is
a
major
component
of
many
soils
developed
in
tropical
and
temperate
climates.
It
commonly
occurs
as
fine,
white
to
cream-colored
clay
and
is
a
key
constituent
of
many
lateritic
and
residual
soils,
as
well
as
sedimentary
deposits.
It
is
mined
worldwide,
with
large
deposits
reported
in
China,
the
United
States,
India,
Brazil,
and
parts
of
Europe
and
Africa.
scale),
and
a
low
specific
gravity
around
2.6.
It
is
non-swelling
and
exhibits
high
whiteness
and
brightness,
making
it
valuable
as
a
pigment
and
filler.
It
is
highly
fine-grained
and
chemically
inert
in
many
applications,
which
contributes
to
its
wide
use
in
industry.
filler
or
coating
in
paper,
plastics,
rubber,
paints,
and
cosmetics
(kaolin).
Calcination
of
kaolinite
produces
metakaolin,
a
reactive
additive
used
as
a
pozzolanic
material
in
cement
and
concrete.
In
geology
and
archaeology,
kaolinite
is
a
common
indicator
of
weathering
and
soil
formation
processes.