- Title
- Investigating bubble-particle interactions in the presence of an ultrasonic field
- Creator
- Mitra, S.; Evans, G. M.; Nguyen, A. V.
- Relation
- IMPC 2020: XXX International Mineral Processing Congress. IMPC 2020: XXX International Mineral Processing Congress (Cape Town, South Africa 18-22 October, 2020)
- Publisher
- Southern African Institute of Mining and Metallurgy (SAIMM)
- Resource Type
- conference paper
- Date
- 2020
- Description
- As an alternative to the conventional flotation method, there has been a continual research effort to enhance the base metal ores and combustibles recovery using ultrasonics. These studies however were largely limited to the pre-treatment of ores for removal of surface contaminants while the effect of ultrasonics on the bubble and pulp-phase interactions remained rather unexplored. Noting this deficiency, this study aimed to investigate the mechanistic effect of an ultrasonic field in an impeller less flotation cell specifically focusing on the bubble-particle interaction dynamics. A lab-scale flotation cell (capacity 1 litre) was designed involving a vertically oriented ultrasonic probe (20 kHz, rated at 1.2 kW) and operated in the output power range from 1 to 20% with continuous liquid recirculation. Particle suspension was achieved by combined action of recirculation and ultrasonic pulses. Interactions of coarse size glass ballotini particles (D32 = 314 µm) with bubbles (< 1 mm diameter) in the presence of surfactant were studied using high-speed imaging. Application of ultrasonic pulse in the aqueous medium resulted in the generation of numerous microbubbles which increased with increasing input power and duration of the ultrasonic pulse time. Such periodic pulses introduced high level of turbulence in the pulp phase facilitating adequate bubble-particle contacts. Microbubbles played a key role in forming particle clusters which were observed to be floatable even in absence of any carrier bubbles. When carrier bubbles were introduced, some of these particle clusters attached to the bubble surface and conveniently floated. It was noted that a favourable state of bubble-particle interactions was achievable to produce stable bubble-particles aggregates by suitably controlling the input power and period of the applied ultrasonic pulse.
- Subject
- flotation; bubble-particle interactions; collision; attachment; detachment; ultrasonic pulse
- Identifier
- http://hdl.handle.net/1959.13/1438695
- Identifier
- uon:40692
- Language
- eng
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