Particle motion in the froth
The froth phase is important for high grade and recovery rate of the flotation process. High pulp water content increases the extraction of unwanted particles. Application of wash water to froth can increase the grade. Excessive drop-back of valuable particles from the froth reduces recovery rate.
Nevertheless, behavior of the froth is not sufficiently investigated because suitable experimental methods are missing.
- Development and application of measurement methods for liquid and particles in the froth
- Development of instrumentation for flotation reactors.
- Understanding of the interaction of hydrophilic and hydrophobic particles with the water content in froth
- Neutron imaging
- Particle-tracking algorithms
- X-ray tomography
Neutron imaging is well suited for the Investigation of froth, because water and some rare earth metals attenuate neutrons very strongly.
Neutron Imaging is a suitable technique for tracking of 200 \mu m Gadolinium particles in froth and measuring the liquid content at the same time
The Ultrasound-Doppler-velocimetry has been successfully applied to foam flow. Thus, UDV is the first velocity measurement technique for 3D foam flow with reasonable temporal and spatial resolution (2.5 fps, 2 cm) and reasonable uncertainty (15%). The influence of particles on UDV measurement is recently investigated. UDV instrumentation is robust and may be installed at an industrial flotation cell.
S. Heitkam, M. Rudolph, T. Lappan, M. Sarma , S. Eckert , P. Trtik , E. Lehmann, P. Vontobel, K. Eckert. Neutron imaging of froth structure and particle motion. Minerals Engineering (submitted)
R. Nauber, L. Büttner, K. Eckert, J. Fröhlich, J. Czarske, S. Heitkam. Ultrasonic measurements of the bulk flow field in foams. Physical Review E (submitted)