The mixing characteristics of solid and liquid phases in a flotation column

This paper presents results obtained in determining the residence time distribution (RTD) characteristics of the solid and liquid phases in a laboratory column and two industrial columns using radioactively labelled solid and liquid tracers. The dispersion model is shown to be superior to other models in describing the RTD in columns with diameter between 10cm and 150cm. Smaller diameter columns can be modelled using either the dispersion model or the tanks-in-series model and larger columns can be modelled using the latter model. Feed and gangue material produce similar tailings age distribution curves. The solid dispersion coefficient is larger than the liquid dispersion coefficient. The solid dispersion coefficient increases with increasing particle size in the laboratory column but remains constant with increasing particle size in the large columns. A modified correlation is proposed to predict the solid dispersion coefficient in large columns.