Chemical Engineering Science, Vol.65, No.11, 3518-3527, 2010
Dispersion kinetics of nano-sized particles for different dispersing machines
For many applications nanoparticles have to be suspended in a fluid phase and dispersed into primary particles or to a definite agglomerate size. Thereby, the prediction of these dispersion kinetic is important among others for comparing the energy efficiency of different dispersion machines. The kinetic models existing today are not able tod escribe the kinetics over the entire process time corectly. Moreover, a prediction of the dispersion kinetics for new process parameters is not possible. For characterizing the dispersing process and deriving and enhanced model for the dispersion kinetic the stress intensity and the number of stress events in different dispersing machines were investiged. The dispersion kinetic was investigated by dipsersing Alumina Alu C (Aeroxide (R) Alu C, evonoik) in distilled water and glycerol using a dissolver, kneade, 3-roller-mill and stirred media mill. Based on these investigations a new modle was developed which is able to describe the dispersion process for different dispersing machines and operating parameters with high accuracy. The new model allows the predictio of the minimum rechable end-particle-size in the studied idspersion process and at varying process parameter based on only a few data points. Within the new model the dipsersion kinetics depends on two fit parameters, which are new only a function of stress intensity and stress frequency alone. Moreover, using the charcteristics parameters stress intensity and stress number the dispersion kinetics for new process parameters can be predicted. (C) 2010 Elsevier Ltd. All rights reserved.