RECENT DEVELOPMENTS IN THE UNDERSTANDING OF FOAM GENERATION AND STABILITY

An illustrative review of recent developments in understanding of foam generation and stability is presented here. Processes of aeration are considered such as injection through orifices and entrainment by rotary mixing vessels. The relationship between bubble sizes and process condition is explored. The effect of surfactant supply rates on foam generation and recent developments in understanding of the antifoam mechanism of hydrophobic particles and particle/oil mixtures are described. A number of mathematical descriptions of foam behaviour which model syneresis (drainage), diffusional disproportionation and film collapse have been made in recent years. Mostly they consider only one or two of these processes (although one model ambitiously purports to account for all of them). Some of these models are reviewed here.