MODELING BUBBLE RECOVERY PROCESSES IN A VIDEO IMAGE

Abstract

A study of the gas motion through the froth of a prototype bi-dimensional
flotation cell was performed. Using video and image analysis techniques, surface
velocity data measured with a Visio froth system were validated by comparing
those results with estimations from manually tracking the motion of the bubbles on
the froth surface. Images used to manually track the bubbles were recorded using a
high-speed video camera. In addition, discharge velocity profiles were measured as
a function of the froth height over the launder lip for two froth Crowder angles
and two superficial air rates. An increasing froth discharge velocity from the lip
level up to the top of the froth was observed. Based on these results, the air
recovery was estimated using the velocity profile and these values were compared
with those obtained using the surface velocity estimation. Results showed
differences from 24% to 47% in the air recovery when the froth flow area at lip
was employed. However, both approaches presented the same trend when
the JG and the froth Crowder angle were changed. Using the top-of-froth velocity
along with the froth flow area at the Visio froth location allows air recoveries to be
closer to those obtained from the discharge velocity profile at lip