APPARENT HINDERED SETTLING IN A GAS-LIQUID SOLID COUNTERCURRENT COLUMN

A bubble wake model has been developed to estimate the net downward velocity of particles in a slurry-contacted countercurrent with a bubble swarm. The concentration of particles in the liquid rising in the bubble wake relative to the concentration in the descending liquid is the major factor in the apparent increase in particle slip velocity. Particle retention time in columns at laboratory scale (3. 8 cm diameter) and industrial scale (flotation column, 45 multiplied by 45 cm square section) are well described by the proposed model.