What is the difference between calcined kaolin and washed kaolin?
Calcined kaolin and washed kaolin are two common methods for processing kaolin (a clay containing aluminum silicate minerals), and they have different effects and applications:
Calcined kaolin is a high-temperature calcination process for kaolin, usually carried out in the temperature range of 800°C to 1,200°C. This process can change the structure of kaolin, causing it to lose adsorbed water and other volatile substances. After calcination, kaolin usually becomes more stable and less susceptible to moisture, and its molecular structure will also change, with higher whiteness and purity, suitable for ceramics, refractories, and other fields. Calcined kaolin is often used in the ceramic industry, refractories, coatings, plastics, and other fields.
Washed kaolin is made by soaking kaolin and washing it with water to remove impurities and other substances, usually organic matter, mineral impurities, etc. After washing, kaolin is usually purer, removing some non-kaolin components, and can be used for more demanding applications. After washing, kaolin is often used to prepare high-quality ceramics, rubber, pharmaceuticals, food additives, and other products, which are required in high-quality fields.
which are required in high-quality fields.
In general, calcination changes the structure and properties of kaolin, making it more suitable for specific industrial uses. It has the characteristics of high whiteness, high hiding power, good weather resistance, and acid and alkali resistance, while water washing removes impurities and improves purity. The process cost is low, the water content is high, and the whiteness is low, but it is suitable for occasions with high requirements for impurities and low requirements for water and whiteness.