Effects of Particle Size, Shape, and Density on the Performance of an Air Fluidized Bed in Dry Coal Beneficiation

Abstract

We consider here the implementation of dry coal beneficiation using air fluidized bed technology. Although the applications of the fluidized bed dry coal separator have been done successfully on an industrial scale in the past, the process has been characterized by relatively poor Ep values. In this study, a 40 × 40 × 60 cm dry batch air fluidized bed coal separator with a relatively uniform and stable average magnetite-silica bed density of 1.64 was used for the detailed separations test using particles of the different densities, shapes, and sizes ranging from +9.5–53 mm. The separation tests were conducted at relatively low throughput and average Ep values as low as 0.05 were recorded for the separation of +37–53 mm and +22–31.5 mm particles. On the other hand, the separation of the +16–22 mm and +9.5–16 mm particles was characterized by relatively high average Ep values of 0.07 and 0.11, respectively. The continuous shift of the cut density for the +9.5–16 mm made it difficult to efficiently separate the particles. Particle shape is a difficult parameter to control, but the observed separation trends for the +16–22 mm particles of different shapes indicate that it has a significant effect on the separation performance of the dry air fluidized bed just like other parameters such as particle size and density.