Authors: Dongdong Wang; Huaifa Wang
Addresses: College of Mining Engineering, Taiyuan University of Technology, Taiyuan 030024, Shanxi, China ' College of Mining Engineering, Taiyuan University of Technology, Taiyuan 030024, Shanxi, China
Abstract: The role of bubble and flotation reagents in the recovery of coal particles in three-phase gas-solid-liquid fluidised beds is investigated in this study. The flow rate and flotation yield in the presence or absence of bubbles were determined. The effect of bubbles attached to lower density and larger coal particles experiencing fluidised bed flotation is also discussed and validated by captured images. It is found that upward bubbly flows can significantly decrease the superficial velocity of liquid required to keep particles suspended and facilitates the capture of particles by bubble. The presence of a flotation collector improves this process and a decreased superficial flow velocity creates a relative quiescent hydrodynamic condition that enhances coarse particle-bubble aggregation and weakens the detachment of coarse particles from bubbles. The results indicate that flotation in a three-phase fluidised bed is a promising method to improve coarse coal particle separation. [Received: May 23, 2016; Accepted: February 13, 2017]
Keywords: coarse coal particles; flotation; three-phase fluidised bed; upward bubbly flow; reagents.
International Journal of Oil, Gas and Coal Technology, 2018 Vol.17 No.2, pp.222 - 237
Received: 23 May 2016
Accepted: 13 Feb 2017
Published online: 26 Jan 2018 *