Gas dispersion measurements in microbubble flotation systems

This work summarises results of microbubble dispersion parameters in a controlled laboratory system. The effects of the temperature and frother concentration (MIBC) on the gas holdup (εg), superficial area flow density (Sb), superficial air velocity (Jg), bubble Sauter diameter (d32) and air liberation efficiency were studied. The results obtained with natural water show that (a) increasing the temperature from 10 to 30 °C significantly increased the bubble Sauter diameter from 80 to 150 μm, improving the air liberation (bubble formation) and (b) increasing the superficial air velocity from 0.01 to 0.06 cm/s enhanced the air holdup from 0.4% to 1.8%, the Sauter diameter from 60 to 120 μm and the bubble surface area flux from 5 to 25 s−1. The experimental results also showed that frother addition (MIBC) reduced the Sauter diameter, while increasing all other variables.

► The effect of temperature and MIBC concentration on microbubbles dispersion were studied.
► The studied variables were gas holdup, superficial area flow density, air velocity, bubble diameter and air liberation.
► The results that increasing the temperature increased the bubble diameter, improving the bubbles formation.
► Increasing the superficial air velocity enhanced the air holdup, the Sauter diameter and the bubble surface area flux.
► Frother addition (MIBC) reduced the Sauter diameter, increasing all other variables.