Fine Coal Beneficiation using an Air Dense Medium Fluidized Bed

The potential of using Air Dense Medium Fluidized Bed (ADMFB) separation for cleaning sub-bituminous coal was investigated. The effect of operating parameters such as the fluidizing air velocity and medium particle size on separation efficiency was determined with coal of various size fractions. Good separation efficiencies with raw coal in the 6 to 1 mm size fraction were achieved. Partition curves showed an E p value of 0.03 for coal in 5.6 to 3.35 mm size fraction. For the 1.00 to 0.42 mm size fraction, the separation efficiency deteriorated to an E p value of 0.10. To achieve an optimum separation efficiency, a separation medium with a narrow and distinct size fraction is needed to allow a superficial gas velocity sufficiently high to create a pseudo fluid medium bed while sufficiently low to avoid back mixing of fine coal and lifting of fine size mineral matter during fluidization.