Froth Flotation

Froth flotation is an essential process in ore dressing. Several billion tons of ore are separated into valuable minerals and worthless gangue by flotation every year. But related methods also play an important role in paper recycling, wastewater treatment and, in the future, perhaps in the recycling of electronic waste.

In froth flotation, the material finely ground and suspended in water. Collector surfactants selectively hydrophobize the valuable mineral particles. These then adhere to introduced air bubbles and are carried to the surface. There, a froth is formed which flows off and thus extracts the mineral particles.  

Although flotation has been used for more than 100 years, basic processes are not yet understood. With our research, we want to contribute to making flotation processes more resource-efficient and effective.

We focus less on the complete process but rather on selected sub-processes:

We research the particle-bubble attachment employing optical particle tracking or positron emmision particle tracking. A key role here plays the surface mobility of the bubble, partially covered by surfactants.

Together with industrial partners we develop, characterize and improve novel downcomers or flotation cell designs.

Also, we research the processes inside the froth zone.

As particle slurries are typically opaque, we develop novel measurement tools for academic research as well as industrial process control, including ultrasound, X-ray or neutron radiography, advanced image analysis, or resistivity measurement.

Finally, we also research related processes such as the Flotation of protein and enzymes, Flotation of microalgae, or the Removal of inclusions in liquid metal by flotation.