ULTRASONIC FRAGMENTATION OF AGGLOMERATE POWDERS

A theory for ultrasonic fragmentation of agglomerate particles suspend ed in liquids is presented. Imploding cavitation bubbles rupture the a gglomerates. An expression for the fragmentation rate as a function of ultrasonic power and agglomerate size is derived. A sectional model f or fragmentation is used to simulate the evolution of the particle siz e distribution of silica and titania powders suspended in water. The f ragmentation rate expression is evaluated by comparing simulated with experimental size distributions at the self-preserving limit. The requ ired time and energy for particle size reduction is calculated as a fu nction of ultrasonic power input.