Neutron imaging of particle laden Foam

This presentation reports on the simultaneous measurement of foam structure and attached particles employing neutron imaging. An aqueous foam sample is placed in the NEUTRA beamline at PSI, enables for achieving a spatial resolution of less than 200 μm at a frame rate of more than 1 Hz. A forced drainage setup allows to control the liquid content of the foam. The averaged attenuation of the neutrons is demonstrated to yield the liquid fraction of the foam. Hydrophobized gadolinium particles of 200 μm diameter are added to the foam. Using two surfactants different levels of hydrophobicity are achieved. Depending on the drainage flow and the hydrophobicity, the particles are washed out of the foam with different rates. An avalanche-like motion of particle clusters is observed. The neutron radiography is demonstrated to yield unique insights into the unsteady froth flotation process.