Dry beneficiation of fine coal using density-segregation in a gas–solid fluidized bed

Abstract

Dry beneficiation of fine coal of +150–500 μm in size was conducted using density-segregation in a gas–solid fluidized bed without any separation media. The coal particles in a cylindrical column (inner diameter = 100 mm and bed height = 100 mm) were fluidized at a given air velocity u0/umf = 1.3–3.0 for thirty minutes where u0 and umf are the superficial air velocity and the minimum fluidization air velocity, respectively. The bulk density of the coal particles in each layer 10 mm in height (ten layers in total) was measured after the fluidization to investigate the segregation. It was found that the maximum segregation is produced at u0/umf = 2.0; the segregation is less pronounced at smal..