Contact
Prof. Dr. Kerstin Eckert
Director Institute of Fluid Dynamics
Fluid Dynamics Resource Technology
k.eckert
hzdr.de
Phone: +49 351 260 3860
Dr. Sascha Heitkam
Head Foam and Froth Flows
s.heitkamhzdr.de
Phone: +49 351 260 3925
Dr. Till Zürner
t.zuernerhzdr.de
Phone: +49 351 260 4714
Froth Flotation
Motivation
Froth flotation has been used for over one hundred years in mining. Several billion tons of ore are processed every year to extract valuable metals. While the technology is well established for many decades, the declining quality of mined ores forces process engineers to improve on existing solutions. Our department works closely with industrial partners to understand the phenomena present in flotation facilities to make their energy and resource usage more efficient, as well as to open up avenues towards novel design ideas.
In addition to the mining industry, flotation is used for cleaning materials (e.g. mineral oils), de-inking of paper, and recycling of old batteries.
What is froth flotation?
Flotation separates different particle types based on their hydrophobicity, i.e., how waterrepellent they are. When air bubbles are rising through a slurry of water and particles, hydrophobic particles attach to the water-bubble interface and are carried to the water surface. There, they form froth, a particle-laden foam, which can be removed and contains a concentrate of hydrophobic particles. Any hydrophilic particles remain in the slurry and are rejected as tailings. Depending on the minerals present in the ore, a special combination of chemicals (so-called surfactants) can condition the particle surfaces, so that only the desired particles containing precious metals and rare earths are floated.
Many specialized flotation cells have been developed over the past decades, tackling a variety of challenges:
- Coarse particles (> 100 µm) or (ultra-)fine particles (< 10 µm).
- Reduce the water consumption and size of the facilities.
- Increase the throughput of material.
What is our approach?
We use sophisticated measurement methods to thoroughly investigate the motion in these complex three-phase systems (mineral particles, air bubbles and water). Developing novel sensor technology does not just further our scientific understanding, but can also be developed towards real industrial applications, as the high amount of dispersed solids and bubbles prevent many commonly applied sensing principles. This allows for the monitoring of processes as they happen and live adjustment of control parameters, resulting in more energy-efficient usage of resources and higher quality products. We are closely working together with the other departments of the Institute of Fluid Dynamics, the Helmholtz Institute Freiberg for Resource Technology (HIF) and the Department of Research Technology.
