The influence of suspension properties on ultra-fine grinding in stirred ball mills

Abstract

The mills traditionally used for wet ultra-fine grinding are high-speed stirred ball mills. The aim of the research was to investigate the influence of the solid (limestone) concentration and of the concentration of sodium polyacrylate on the apparent viscosity and the grinding efficiency. With increasing solid concentration the energy utilisation initially increases up to a maximum, and then it decreases because of the rising viscosity. The used additive acts as dispersing agent, it improves the charge of the particles and reduces the apparent viscosity. This causes a displacement of the maximum energy utilization to higher solid concentrations. Thus, there are two different ranges of the effect: for lower solid concentrations the surfactant gives a smaller energy utilization, but for higher concentrations a larger one. In the latter case it is possible to produce higher specific surface areas at the same apparent viscosity.