In-process monitoring of material flows in froth flotation with model-based ultrasonic measurement technology
In 2016 about 20 billion liters of water were used, only to extract copper as a raw material. The process used is the froth flotation. Grained materials are being separated by the use of surfactant solutions. Ascending bubbles transport the hydrophobic materials to the surface, consisting of a bulk foam layer. Due to different material and water qualities, a robust effective process is only partly possible. Information about the material flow might increase these factors.
Scheme of a flotation cell and the measurement setup
Our aim in that project is to implement a measuring system, giving information about the foam’s consistence and the material flow. Conventional optical measurements or level sensors provide a too low penetration depth in opaque bulk foam or give too little information about the foam parameters respectively. Therefore, we use an in-situ ultrasound measurement system. An ultrasound array is used to create a 2D-image. Analyzing the variations in the propagated (transmitted/reflected) ultrasound signal due to different foam parameters as liquid fraction, bubble size or the amount of particles, we are able to draw retrospective conclusions about those parameters. Using different signal processing tools as Doppler Analysis we gain information about the particles velocity and their moving direction. Combining those monitored values, we can infer a statement about the material flow. Thereby we are one step closer to a control loop that potentially increases the yield and saves energy and resources.
Staff: H. Emmerich, L. Büttner
Partner: Leon Knüpfer, Dr. Sascha Heitkam, Institut für Fluiddynamik
Helmholtz-Zentrum Dresden - Rossendorf (HZDR)
Period: 06/20 - 01/23
Nauber, Richard; Büttner, Lars; Eckert, Kerstin; Fröhlich, Jochen; Czarske, Jürgen; Heitkam, Sascha. (2018). Ultrasonic measurements of the bulk flow field in foams. Physical Review E. 97. 10.1103/PhysRevE.97.013113
Emmerich, Hannes, Schaller, Ludwig, Nauber, Richard, Knüpfer, Leon, Heitkam, Sascha, Czarske, Jürgen and Büttner, Lars. "Linear, spatio-temporally resolved ultrasound measurement of the liquid fraction distribution in froth" tm - Technisches Messen, vol. , no. , 2021, pp. 000010151520210047. https://doi.org/10.1515/teme-2021-0047