The entrainment characteristics of fine powder from solid mixtures (Geldart groups A and C) in the gas-solid fluidized beds were determined in a conical fluidized bed (cone angle = 10 degrees) and a cylindrical fluidized bed (inner diameter of 0.1 m) with or without a tube (outer diameter of 0.06 m). Alumina particles (group A) were used as the inert medium, and carbon black particles were used as the fine powder (group C). The entrainment rate of fine powders was determined by measuring the initial weight loss from the bed. The effects of gas velocity, the content of carbon black in mixed-bed materials, the type of reactor (conical and cylindrical), and the static bed height on the entrainment rate were determined. The entrainment rate increased as the gas velocity increased but decreased as the content of fine powders in the cylindrical fluidized beds increased. At a given gas flow rate, the entrainment rate constants from cylindrical fluidized beds were 5-12 times higher than those of conical fluidized beds.