A Model of Flotation Selectivity

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A mathematical model of the flotation process was developed having at least two features which can make it a useful tool for flotation analysis.

First, the model includes physically meaningful descriptions of the inter-relationships between bubbles and particles in the flotation process. This makes the model a more reliable predictor of flotation result changes than, for example, a regression curve fitted to experimental data, but having no causal meaning.

Second, once the model is fitted to a given process, it significantly simplifies a search for physical conditions optimizing that process. Computer simulations can be used instead of experiments, or can be employed as screening tests before commencing an experimental program. The model can indicate where the process conditions are located with respect to the optimum conditions, thus showing the directions of necessary adjustments.

The model has several inherent limits of its application as well, caused by the model's structure and by simplifying assumptions made throughout its development. The most significant limitation arises from the fact that, at this stage of its development, the model requires several empirical coefficients. This reduces model flexibility, and limits quantitative predictions to that flotation system to which the model has been fitted.

Another limitation is caused by the fact that effects of the flotation chemical conditions are expressed by lumped parameters. Thus the model cannot be used to simulate any effects of collector or frother concentrations on the flotation results. Constitutive equations describing the influence of flotation reagents on the collection efficiency and on gangue entrainment into the froth would alleviate this shortcoming of the model.

The model presents a relatively simple description of the extremely complex process of froth flotation. The comparisons of model predictions with experimental results showed that the model can provide sufficiently accurate predictions of changes in the flotation results induced by variations of process conditions. However, it should be kept in mind that the model has been validated for a limited number of applications, and for the batch type flotation only. It still requires further verification, especially with different flotation systems, to better evaluate all its applications and shortcomings.

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© 1988

Publication Title

International Journal of Mineral Processing