Enhanced dispersing properties of kaolin due to high-strength kneading process

In this study, the influence of high-strength kneading process on the dispersibility of kaolin was investigated. Various factors including crystallinity, shape and interaction energy of kaolin particles were investigated systematically based on XRD, SEM, FTIR, Zeta potential and DLVO analyses. The results showed that the high-strength kneading treatments increased the proportion of kaolinite (001) planes, reducing the friction between kaolin particles but increasing their crystallinity. In addition, this treatment promoted the tendency of kaolin to a pseudo-hexagonal shape. DLVO analyses further showed that the electrostatic repulsion energy between kaolin particles was proportional to the kneading time due to the increased specific surface area (e.g., increased from 14.63 to 18.24 m2 & sdot;g- 1) and negative charge value (e.g., decreased from-15 to-32 mV) of kaolin sample. This correspondingly led to a lower viscosity of kaolin pulp with better dispersing properties, e.g., the viscosity of kaolin samples decreased by 65.41% when kneading time was extended from 0 to 6 h. This study therefore provides a new strategy to reutilize kaolin sources with low dispersing properties and crystallinity after a high-strength kneading process.