Modelling and simulation of threephase flow in flotation equipment
Flotation is a method for separation of particles based on the different hydrophobicity of their surfaces which is widely used in the mining industries for the separation of ores. Recently the importance of selective separation of fine particles (<100 μm) has been increasing, especially when it comes to the recovery of important raw materials such as the rare earth metals which are needed in many current key technologies.
In addition to the chemo-physical properties, the attachment of the particles to the bubbles and the stability of the formed aggregates are particularly determined by the local hydrodynamics. The optimisation of existing or the development of new flotation equipment with systematically improved hydrodynamics therefore has a huge potential to yield more efficient separation with higher selectivity. Hence one obtains a higher recovery especially with reduced energy input.
The aim of this work is the development of a baseline model, which allows for the computation of the local hydrodynamics and flotation rates in industrial size equipment. To this end a locally averaged description of the phases (gas/liquid/solid) has to be used which requires closures for the modelling of the rheology of individual phases as well as their interaction. The experimental validation will be done for a broad range of material parameters and flow conditions such that the model has a general validity. It can therefore be used in industrially relevant problems, in particular to predict the effectiveness of the separation with sufficient accuracy.