Introduction
In the ceramics industry, kaolin (usually referred to simply as "kaolin") is a fundamental and widely used raw material used in the production of ceramic products such as pottery, porcelain, tiles, and sanitary ware. Its main role in the ceramics industry is as a key component in both the body and glaze formulations. Kaolin has the ability to suspend particles, preventing sedimentation, and its plasticity ensures that the glaze bonds tightly to the ceramic body before firing. During firing, kaolin enhances the hardness, chemical resistance, and opacity of the glaze.
As a clay mineral, kaolin is often used as a key component in glaze formulations for pottery and ceramics. Its applications in glaze preparation are as follows:
1. Glaze Suspension: Kaolin is added to the glaze formulation as a suspending agent. It can evenly disperse other glaze components and prevent sedimentation during storage. This ensures the stability of the glaze composition, making it easy to apply to the surface of pottery or porcelain.
2. Adhesion: Kaolin enhances the adhesion between the glaze and the ceramic body. It allows the glaze to adhere firmly to the surface of the vessel, preventing it from running during firing and ensuring a smooth and even glaze surface.
3. Texture and Covering Power: Depending on the particle size and type, kaolin can affect the texture and covering power of the glaze. For example, fine-grained kaolin creates a glossy, smooth glaze, while coarse-grained kaolin produces a matte or satin finish. By adjusting the type and amount of kaolin used, ideal glaze texture and covering power can be achieved.
4. Coefficient of Thermal Expansion: Kaolin affects the overall thermal expansion characteristics of the glaze. By precisely controlling the type and amount of kaolin in the glaze formula, ceramic artists can match the coefficient of thermal expansion of the glaze to the body, thereby reducing the risk of glaze cracking or splitting during firing.
5. Color Development: Kaolin itself is usually white or off-white, but when used in combination with other colorants, it can affect the color development of the glaze. It can enhance the vibrancy of specific glaze colors and act as a toner to achieve specific hues.
6. Glaze Stability: Kaolin enhances the stability of glaze formulations, preventing adverse reactions of glaze components during firing. It helps maintain the chemical and physical integrity of the glaze.
These are the core reasons why kaolin is widely popular in the global ceramics industry.
As an indispensable basic raw material in the ceramics industry, kaolin's multifunctionality in glazes and bodies is particularly significant. It not only ensures uniform application and firm bonding of the glaze through its excellent suspension and adhesion properties, but also effectively prevents glaze cracking by adjusting the coefficient of thermal expansion, significantly improving product yield and aesthetic quality. Furthermore, kaolin's contribution to whiteness and its support for color performance and glaze stability make it a core material for achieving high-performance, high-quality ceramic manufacturing. Scientific selection and proportioning of kaolin is a key technological path to promote the development of ceramic products towards higher quality.