A new pigment disperser for high solids paper coating colors

In paper coating make-down, a poor dispersion of pigments in coating colors may lead to coater runnability problems. This is manifested bt coat defects at the paper surface excessive coater blade wear, and an over-consumption of pigments. For this reason, high shear impellers operated at high speed are used, yielding a high energy consumption. A new method to disperse high solids mix at low energy consumption is presented. This method based on the use of a rod impeller scraping the fluid surface in the vessel, is tested on a slurry composed of calcined and delaminated clays up to a solids content of 66.7 wt.% without dispersing aids.