Kaolin powder is used as a raw material in various industries due to its very special properties. It is used as a white clay or powder, historically known as porcelain clay. The name is derived from a Chinese hill.

What is Kaolin Powder?

The chemical structure of kaolin differs in the type of bonding, so kaolin powder is divided into soft and hard categories. The white-colored powder is used in the production of porcelain and ceramic dishes. Kaolin powder can achieve stability if the pH is in the range of 3 to 9. One of the characteristics of this powder is that it consists of very fine particles.

When mixed with water in the range of 20% to 35%, kaolin becomes plastic and can be shaped after pressure removal. As the water content increases, kaolin forms a slurry or aqueous suspension. The amount of water needed to achieve plasticity and viscosity varies depending on the size of the kaolin particles and any specific chemicals present.

Kaolin is extracted in countries such as France, the United Kingdom, Saxony (Germany), Bohemia (Czech Republic), and the United States, with the most famous deposits found in the southeastern United States.

Types of Kaolin Powder

There are various types of kaolin, and these powders typically contain up to 20% impurities. The most important minerals in kaolin include:

  • Kaolin
  • Dickite
  • Nacrite
  • Halloysite

Applications of Kaolin Powder

Kaolin powder has numerous applications today. It is used in the production of fine white pottery, which is a primary component in ceramic tiles. It is also widely used in industries such as paper, rubber, paints, and many other products. The first examples of kaolin use were discovered in 1700 by a French missionary. Its use is clear in various fields, from ceramic tiles to paper and paint.

"Kaolin is white and fine, primarily made up of kaolin minerals, which, under electron microscopy, form nearly hexagonal crystals ranging in size from 0.1 micrometers to 10 micrometers or even larger."

These crystals may have fibrous shapes and often contain varying amounts of other minerals such as muscovite, quartz, feldspar, and anatase. Additionally, raw kaolin is often tinted yellow with iron hydroxide pigments.

Kaolin slurry is used to improve the tensile strength and modulus of rubber compounds based on calcium carbonate. "Hard kaolin" stones are presented with smaller particle sizes, higher modulus, tensile strength, hardness, and wear resistance for rubber compounds.

80% of soil types used in tire production are of the hydraulic float type, separated from air to remove impurities. Another application of kaolin is in rubber, where solid surfaces exposed to coatings provide reinforcement more effectively than non-metallic soils, with potential carbon black applications in certain contexts. Special properties like air permeability can be achieved in kaolin slurry through a purification process.

Countries Producing Kaolin Powder

Among these minerals, kaolin is one of the most significant. This white-to-yellowish mineral has a strong earthy odor. The bonding structure of kaolin varies, so it is divided into soft and hard types. This mineral is water-soluble, and countries such as the United States, Russia, the Czech Republic, and Brazil are significantly involved in the production of kaolin powder. Kaolin powder can be stable if its pH is within the range of 3 to 9, and thus can be used as a coating, filler, or pigment.