Kaolin

Kaolin is a white clay composed primarily of kaolinite. It is a layered silicate mineral with a single tetrahedral layer of silica (SiO₄) bonded through oxygen atoms to a single octahedral layer of alumina (AlO₆ ₎ .

It is formed by the chemical weathering of aluminum silicate minerals such as feldspar.

The chemical formula of kaolinite, as written in mineralogy, is Al₂Si₂O₃(OH)₄, but in ceramics the same formula is usually written in terms of oxides, giving Al₂O₃·2SiO₂·2H₂O.

Chemical composition of kaolin: 

	Contents, %
Al2O3	22 – 23
SiO2	67 – 68
Fe2O3	0,35 – 0,45
TiO2	0,5 – 0,6
K2O	0,1 – 0,2
Na2O	0,05 – 0,1
CaO	0,2 – 0,3
ВПП (втрати при прожарюванні)	8 – 9

Physical and mechanical characteristics:

Indicator	Value
Bulk density	1.4–1.5 t/m³
Specific density	2.5–2.6 t/m³
Humidity	17-19%
Loss on ignition (LOI)	8–9%

Transportation conditions:

• Transport by rail or road in bulk or in big bags.

Usage :

Construction and Cement:
  Metakaolin (calcined raw kaolin) increases the strength and durability of concrete, reduces the need for Portland cement, improves sulfate resistance. Used in high-performance concrete (HPC), self-leveling screeds, and specialty mixes.

Paper industry:
  Used as a filler (up to 15% of the paper weight) and as a component of the coating layer (up to 25%) to improve whiteness, smoothness, brightness and paint adhesion.

Ceramic industry (tiles, sanitary ceramics, porcelain):
  Raw kaolin, as a key component, provides high plasticity, reduces shrinkage during drying and firing, and ensures whiteness and strength of products (up to 50% in porcelain, 20–30% in faience and sanitary ceramics).

  Ukrainian kaolin is mainly chosen due to its high quality; it retains a significant share in the formulations of European manufacturers.

Glass industry:
  Ukrainian kaolin in raw form is used in the production of float glass.

Rubber, plastics, artificial leather, textiles:
  EU manufacturers, in particular Italian companies, use Ukrainian kaolin as a functional filler for rubber, PVC and artificial leather: to improve mechanical and thermal strength, whiteness.

Paints and coatings:
  Used as an extender pigment: reduces TiO₂ consumption, increases hiding power, controls coating viscosity, improves wear resistance and gloss. Used in both interior paints and automotive and industrial paints.
Electrical insulation, Pharmaceuticals and cosmetics, Agriculture and plant protection and many other areas.