kaolin

الوصف

 Crystal habit
Rarely as crystals, thin platy or stacked, More commonly as microscopic pseudohexagonal plates and clusters of plates, aggregated into compact, claylike masses
Crystal system
Triclinic

Cleavage
Perfect on {**1}
Tenacity Flexible but inelastic
Mohs scale hardness 2–2.5
Luster
Pearly to dull earthy
Streak
White
Specific gravity
2.*6–2.*8
analysis

Chemical Analysis
*7 ±1 SiO2
*7 ±1 AL2O3
0.2 Fe2O3
1.3  ±0.2 TiO2
0.2 CaO
0.*2 MgO
0.*3 Na2O
0.*4 K2O
*3.4 L.O.I
Mineral Composition
*6 kaolinite
3.5 Quartz
CHEMICAL CONTENTS %
*4 ±1 SiO2
*2 ±1 Al2O3
0.3 Fe2O3
1.1  ±0.2 TiO2
0.2 CaO
0.*8 MgO
0.*3 Na2O
0.*6 K2O
*1 L.O.I
MINERAL COMPOSITION %
*4 Kaolinite
*3 Quartz

CHEMICAL CONTENTS %
*8 ±1 SiO2
*6±1 Al2O3
0.3 Fe2O3
1.5  ±0.2 TiO2
0.*8 CaO
0.*2 MgO
0.*7 Na2O
0.*9 K2O
*2 L.O.I
MINERAL COMPOSITION %
*3 Kaolinite
5 Quartz

CHEMICAL CONTENTS %
*8 ±1 SiO2
*4±1 Al2O3
0.3 Fe2O3
1.5  ±0.2 TiO2
0.*8 CaO
0.*2 MgO
0.*7 Na2O
0.*9 K2O
*2 L.O.I
MINERAL COMPOSITION %
*3 Kaolinite
5 Quartz

CHEMICAL CONTENTS %
*0 ±2 SiO2
7 ±2 Al2O3
0.*7 Fe2O3
0.8 ±0.2 TiO2
0.2 CaO
********- MgO
********- Na2O
********- K2O
2.5 L.O.I
  MINERAL COMPOSITION %
*7 Kaolinite
*2 Quartz

general

Kaolinite is a clay mineral, part of the group of industrial minerals, with the chemical composition Al2Si2O5(OH)4.
Is clay rock formed due to dissolution of granite ,or vertical lenses form or sedimentary layers near the surface . may contain greater or lesser quantities of related sheet silicates (mica, illite, chlorite, smectite) and quartz .
- it is inert mineral so not chemically effected , and have power in covering and hidden if it used as coloring agents in filler, painting and tanning leather .
It is also used industrially because its capability to adsorb water , weakness to transmitted temperature and electricity , and it is very cheap ,

Uses :

*- paper industry which consumption about *0 % of world kaolin  production that *0% of paper is kaolin so it become soft , glassy touch , High-brightness, low abrasion water-washed , to improve brilliance,  smoothness, and ink receptivity. .
*- plastic industry : because it give the surface soft touch , resistance to chemicals  , fixed form , and not electric transmitted , reduced cracking, warping and crazing,
*-ceramic industry : it is the essential substance in this industry, they make several tests to measure  pottery coefficient , color degree after firing , shrinkage degree  ,  viscosity degree , degree of firing , casting degree .
*- rubber industry : to increase tension strength , increase corrosion resistance , increase solidification , and also decrease the coast .
 *- painting industry : use due to its chemical inert  and covering pores ,low coast white color , and dissolution in painting ,
*- Refractories :contain flint clay to give a dense, strong product able to withstand much higher temperatures .
*- Adhesives and sealants Kaolin is used to control flow, penetration, and specific adhesion on application, and adhesive strength, tear strength, tensile strength, and elongation after cure.
*- Other Uses Kaolin clays are used in the manufacture of aluminum chemicals, *- bricks,
**-cements,
**-  cosmetics, pharmaceuticals,
**- animal feeds, fertilizers, catalysts, wallboard, printing ink, linoleum, flexible tile, pesticides,
**-Kaolinite can contain very small traces of uranium and thorium, and is therefore useful in radiological dating.
**- Kaolinite has also seen some use in organic farming, as a spray applied to crops to deter insect damage, and in the case of apples, to prevent sun scald.
**- When heated to between **0 and **0 °C kaolinite dehydroxylates to form metakaolin. When added to a concrete mix, metakaolin affects the acceleration of Portland cement hydration when replacing Portland cement by *0 percent by weight.