Interfacial characterisation for flotation: 2. Air-water interface

摘要

The progress in recent years in characterising the properties of the interface between air and water in the presence of commonly used surfactants in mineral flotation (termed frothers) is summarized. The focus of this review is on techniques that provide access to dynamic aspects of frother interactions at the interface between air and water, and those techniques that provide a unique perspective of equilibrium adsorbed layer properties. Profile analysis tensiometry (PAT) and other forms of interfacial tension measurement are described, and recent work highlighted. In addition, the methods of dilational interfacial rheology, which probes the viscoelastic properties of the air-water interface and the influence of dynamic adsorption processes, is discussed in relation to published work on flotation frother, as is work on measurement of rising bubble velocities, which allows probing of the dynamic adsorption layer (DAL). In addition to these more traditional measures of interfacial activity and effect, the study of the air-water interface with vibrational spectroscopy, and its relevance to flotation (with reference to recent published work), is described.