Publish Time: 2026-02-04 Origin: Site
In the world of ceramics, there exists a magical "clay" that functions like a humble, dedicated figure in the background, endowing ceramics with its delicate texture, pure white color, and stable properties. This clay is called ceramic kaolin.
I. Various products, each showcasing its own charm
1. Classified by cause
Primary kaolin: Formed through weathering of silicate minerals such as feldspar. It is produced along with the parent rock and has not been transported. Therefore, it has a coarser particle size and a better crystallization degree. It is often used in the production of ceramic products with low requirements for particle size, such as some architectural ceramics.
Secondary kaolin: This type of kaolin is formed through processes such as transportation and deposition under the influence of natural forces from the original kaolin. It has a relatively fine particle size, high purity, better plasticity and whiteness, and is therefore highly suitable for the production of high-end household porcelain and artistic porcelain.
2. Classified by place of origin
There are high-quality kaolin production areas all over the world, and the kaolin from different regions may have slight differences in composition and properties. For instance, the kaolin from Jingdezhen, China, is renowned worldwide for its excellent quality. The ceramics made from this kaolin have fine texture, warm color, and possess a unique Eastern charm. In the United States, the kaolin from Georgia is favored in the international market for its high whiteness and fine particle size, and is often used in high-end ceramics and papermaking industries.
II. Kaolin: The Inherent "High-Quality Base"
Kaolin, also known as "ceramic clay", gets its name because it was first discovered in Gaoling Village, Jingdezhen, Jiangxi Province. It is a type of clay with kaolinite as its main mineral component. Its appearance is mostly white or light gray, and it has a fine and soft texture. From the mineral composition to the physical and chemical properties, kaolin inherently possesses the "top student" traits, which also lays the foundation for its application in colored glazes.
1. High purity and low impurities
The main component of high-quality kaolin is kaolinite, which can account for over 90% of the total content. The content of impurities (such as oxides of iron, titanium, etc.) is extremely low. This characteristic is of crucial importance - impurities like iron and titanium will cause blemishes during high-temperature firing, affecting the purity of the colored glaze. The "high purity" of kaolin is like a clean canvas, allowing the colors of the glaze to be accurately presented and avoiding problems such as "dirty colors" and "grayish appearance".
2. Good plasticity and adhesiveness
Kaolin has a fine particle structure and, when mixed with water, can form a uniform clay material, demonstrating excellent plasticity. In the preparation of colored glazes, this plasticity enables kaolin to closely combine with colorants, fluxes, and other components, forming a stable glaze slurry that is not prone to layering or precipitation. At the same time, its adhesiveness can also enhance the adhesion between the glaze and the body, reducing the risk of glaze cracking and peeling during the firing process.
3. Higher fire resistance
The refractive temperature of kaolin is usually above 1700℃, which is much higher than the firing temperature of ordinary ceramics (1200 - 1400℃). This means that during high-temperature firing, kaolin itself will not easily melt or deform, providing a stable "framework" for the color glaze, supporting the glaze layer to maintain a complete shape, and at the same time avoiding the influence on the melting range and glossiness of the color glaze due to its own melting.
4. Unique suspension and dispersion properties
Kaolin particles have excellent suspensibility in water and can be evenly dispersed in the glaze slurry without rapid sedimentation. This property ensures that the color glaze material maintains a uniform concentration during the glazing process, resulting in consistent glaze colors on the surface of the objects and avoiding defects such as "color differences" and "spots", allowing each ceramic work to present a unified aesthetic appeal.