How to choose the grinding medium of the grinding mill
There are many kinds of grinding media used by the sand mill, such as glass beads, corundum magnetic beads, zirconium beads and steel balls, different dispersion media, and there are also differences in water or oil based system, the grinding efficiency of the color paste is not the same, so coating engineers need to select.
Different densities of grinding media are used for different material viscosity. High density grinding medium ball, can get a large impact, impact and shear force will increase accordingly, high dispersion efficiency. However, the influence of slurry viscosity should be considered in the application. If the slurry viscosity is large, the grinding medium with high density should be selected. Otherwise, it will not only have little effect on improving the dispersion efficiency, but also lead to the serious wear of the grinding medium and parts. Glass bead density of 2.4-2.59/cm3, suitable for low viscosity paint.
The particle size of grinding medium also has great influence on the dispersion efficiency. In general, the finer the fineness required by the product, the smaller the diameter of the grinding medium is, because the smaller the diameter of the medium, the greater the probability of shearing between the spheres and the collision, and the dispersion efficiency will be improved. But if the ball diameter is too small, the dispersed kinetic energy is too small to disperse the pigment aggregate, and the beads are too small, easy to block the screen, the dispersion efficiency is reduced. At present, the commonly used glass bead grinding medium diameter is 0.5mm, 0.75mm, 1.0mm , coating engineers need to choose suitable according to the specific process.