Effect of particle size and shear parameter on the characteristic of particle-bubble cluster in high-intensity conditioning of coal

Abstract

ABSTRACT Recent studies have reported that particle-bubble clusters formed and are deduced to play a potentially important role in high-intensity conditioning (HIC). In this study, the effect of particle size and shear parameter on the characteristic of particle-bubble cluster in HIC of coal was investigated in details. Results showed that, for coal of +75 μm fraction, the number of bubbles and the mean bubble diameter generated by pusher blade and sawtooth-disk blade were close. By contrast, the effect generated by four-pitched blade was inferior. The number of bubbles is fairly related with particle size. Under the same conditions, compared to that of +75 μm fraction, the number of bubbles attached to the coal surface of 45 ~ 75 μm is 1 to 2 orders of magnitude less. The mean diameter of the bubbles also tends to decrease in the same way. Particle-bubble cluster was also found in the fraction of −45 μm coal. Compared to the other two blades, the number of bubbles generated by pusher blade was the largest. In summary, pusher blade produced the best performance of cluster formation for each particle size fraction. This study is expected to provide guidance for the optimization of shear parameters for cluster formation during HIC.