The influence of discharge style on the separation of coarse coal slime by a hindered fluidized bed

Two kinds of liquid distributor, a central discharge or a peripheral discharge, were designed into a hindered fluidized bed separator. The beneficiation performance of the fluidized bed was investigated using 0.25∼1.00 mm coarse coal slime and the two different distributors. The experimental results show that the heterogeneity of axial particle velocity in the radial direction of the bed can be reduced by a distributor that has a central discharge. The beneficiation performance for this distributor is improved relative to the distributor with the peripheral discharge. This indicates that it is necessary to eliminate or suppress the core-annulus structure within a hindered fluidized bed. Increasing superficial water velocity causes the clean coal ash content, the tailings ash content, and the combustible recovery to increase. Additionally, increasing the bed height decreases all of these three indexes. The optimum superficial water velocity and bed height for a 0.25∼1.00 mm coal feed were determined to be 3 mm/s and 800 mm, respectively. This work provides a foundation for the scale-up of the bed.