A Study of Detachment of Model Coarse Particles from Bubbles Using a Novel Electro-Acoustic Technique

Abstract

In this paper, a detachment of particles from bubbles was investigated using a novel electro-acoustic technique. The experimental setup consisted of a loudspeaker connected to a computer through an amplifier. A teflon capillary tube was attached to the membrane of a loudspeaker. A bubble-particle aggregate on the other end of the capillary tube was subjected to vibration when the sinusoidal signal of fixed frequency and amplitude generated by the computer was transmitted to the loudspeaker. The critical amplitude of particle detachment was determined at a fixed frequency (50 Hz). The detachment experiments were conducted using model quartz particles of various size and hydrophobicity. Results showed that particles (600-850 m) with high contact angle (90 degree) required high amplitudes for detachment from bubbles. In contrast, quartz particles with low contact angle (49 degree) exhibited the considerably lower critical detachment amplitude. The critical detachment amplitude was related to the stability of bubble-particle aggregates. The results of electro-acoustic experiments correlated well with the outcomes of corresponding bench flotation tests.