Changes of size, ash and density of coal particles on the column axis of a liquid–solid fluidized bed

The liquid–solid fluidized bed has been widely applied in the separation process of coarse coal particles. The coal slurry should be classified before feeding into the liquid–solid fluidized bed. The most of fine coal particles, with the particle size less than 0.2 mm or 0.3 mm, should be removed from the coal slurry in the feeding. However, there are still amounts of fine coal particles which cannot be removed due to low classification efficiency. The separation process may be affected by these fine coal particles which always enter in a part of the clean coal without effective separation process. This investigation was carried out to determine the effect of fine coal particles on the separation process of liquid–solid fluidized bed. A liquid–solid fluidized bed was designed and eight sampling points were fixed on the column axis. The changes in size, density and ash content of coal particles were observed on the column axis and the partition coefficients of + 0.25 mm and − 0.25 mm fractions were obtained.