The increasing particle-particle-interactions with increasing fineness are an essential problem during wet comminution in stirred media mills. These interactions have an influence on the stability of the product suspension towards agglomeration and on the rheology. Experimental results show that during comminution the measured particle size increases again after reaching a product fineness of approx. 500 nm, although a further increase of the specific surface can be determined (BET-method). The reasons for this phenomenon are the increasing particle-particle-interactions and spontaneous agglomeration.
Possibilities of the stabilization of the product suspension in the stirred media mill are therefore mainly discussed in this report. With respect to this, first results of sample preparation are mentioned. It is shown that during the comminution changes of the pH value, the conductivity and thus the ionic strength as well as the zeta potential occur in dependence of the materials of the grinding chamber lining and the stirrer discs as well as the grinding media material and the product material. In further investigations the product suspension shall be stabilized electrostatically during the grinding process.
The comminution progress as well as the electrochemical properties of the product suspension shall be characterized by online measurements. For this measurements a possible experimental set-up is introduced and discussed. Only after this steps the systematic investigations concerning the influence of the grinding media size are reasonable.