Effect of Dispersants Pre-adsorption and Grinding on Dispersion Performance of Kaolin Pigment

摘要

The solid content of kaolin pigment suspension used in paper coatings must be as high as possible in order to minimize the drying cost. X-ray photoelectron spectroscopy (XPS) analysis on elemental compositions showed that, the kaolin combined less dispersants possessed worse dispersion capacity. Therefore, the effect of pre-adsorption of organic or inorganic negatively charged polymers sodium polyacrylate(PAA) and sodium hexametaphosphate(HMP) on the dispersing performance of concentrated kaolin suspensions was investigated, moreover, the effect of pre-adsorbing with or without grinding processing was evaluated. It was found that the viscosity of PAA pre-adsorbed kaolin decreased considerably, probably due to the stronger electrostatic repulsion. And grinding treatment had a dramatical influence on the dispersing behavior of kaolin with PAA pre-adsorbed on, resulting in low relative viscosity at high solid content.