Agglomeration of fine hydrophobic particles: 1D and 2D characterization by dynamic image analysis of in-line probe data

Abstract

The agglomeration dynamics of small poorly wetted alumina particles with a wetting angle of 134° was investigated in a baffled stirred tank by dynamic image analysis with an in-line camera probe. Dynamic image analysis of the in-line probe data allows for a multidimensional characterization of particle properties during the agglomeration process, that was evaluated with respect to the particle size, aspect ratio, and solidity of the primary particles and the agglomerates generated. Agglomeration of the particles in 0.75 mol/l sodium chloride solution leads to the formation of a bimodal particle size distribution, where the first mode represents non-agglomerated primary particles and the second mode represents the agglomerates with an equilibrium size that is smaller than the corresponding Kolmogorov microscale. The bimodal size distribution can be approximated by mixture models based on 1D size or 2D size-aspect ratio data, from which the fractions of agglomerates and primary particles can be determined.