Measuring Flowing Foam Density Distributions Using ERT

J.J. Cilliers, M. Wang and S.J. Neethling

Froth and Foam Research Group, Department of Chemical Engineering, UMIST, P.O. Box 88 Manchester, M60 1QD, U.K.

E-mail: j.j.cilliers@umist.ac.uk

Abstract - In process industries where froth flotation is used, such as mineral production and paper de-inking, the froth structure required for effective particle separation is very specific. The froth structure is different at various heights in a flotation column and influences the separation achieved. In all of these systems, the fragility and opacity of the system and the associated process conditions make the use of non-intrusive characterisation techniques a necessity.

Three techniques are described; firstly image analysis of the surface of the froth, and secondly visual modelling of a cross-section through a flowing foam. Finally, the use of ERT for exploring the internal structure of a foam column is described. This shows that zones of coalescence within the column can be detected and which can subsequently be used to compliment the surface characterisation and verify the visual model. Other potential application of this measurement technology to foams are discussed.