Kaolin is widely used for ceramic and refractory materials, followed by paper, coating material, paint, building materials, rubber and other industrial raw materials. In recent years, with the rapid development of China's paper industry and paint and paint industry, the demand for high quality kaolin products in the industry is increasing year by year, and the market gap is large. However, there are less and more high quality kaolin resources with high white and high purity in nature, which can not meet the requirements of the market. The water washing kaolin is an ideal raw material used in papermaking coating in China. It has the characteristics of strong covering power, high whiteness and uniform particle size distribution. It is easier to improve the printability, ink absorbency and finish of paper in the process of paper coating. Calcined and washed kaolin is one of the means to prepare high-quality kaolin. It has good prospects for development and application.
In industrial production, kaolin processing technology can be divided into dry process and wet process. Wet dressing process is usually adopted for soft kaolin and sandy kaolin. The main process of kaolin wet process is coarse kaolinite coarse crushing, pulping purification, classification, mechanical superfine grinding, centrifugal dewatering, drying and grinding.
In order to disperse the kaolin well, it can be stirred at the side, and a small amount of dispersant can be added if necessary. Commonly used dispersants include sodium carbonate, sodium silicate, sodium polyacrylate, tripolyphosphate and sodium six phosphate. According to the theory of the friction force in the pulp, the dispersing mechanism of the particle and the influence factors of viscosity, the influence of various dispersants on the viscosity of the pulp after the mixed use of the dispersants was tested by the Eun's viscometer, and the method to effectively reduce the viscosity of the Maoming water washing kaolin was to adjust the pH value of the pulp and add the reasonable dispersing agent DC and STPP.