De-agglomeration of goethite nano-particles using ultrasonic comminution device

The effect of power input, solid content and ionic strength of liquid on the kinetics of de-agglomeration of acicular goethite nano-particles in ultrasonic comminution device has been investigated. It has been found that the pattern of de-agglomeration is independent of power input. Initially large aggregates are broken by fragmentation and as the process progresses the primary particles are gradually eroded from the surface of those large aggregates. The breakage of large aggregates was described by size-energy model and the model describing the generation of primary particles was developed. The increase of solid concentrations in the suspension (up to 20 wt.%) leads to an increase of the efficiency of both breakage of large aggregates and formation of fine particles. The ionic strength and solid concentration have practically no effect on mechanism of de-agglomeration but they affect the morphology and rheology of the suspensions of goethite nano-powder.

Large aggregates are initially broken by fragmentation and followed by gradual erosion of primary particles from the surface of aggregates. The breakage of large aggregates was described by size-energy law and the model describing erosion of primary particles was developed. The effect of concentrations of solid and salt on de-aggregation and the viscosity of suspensions are also discussed.Figure optionsDownload as PowerPoint slide