Twelve narrow fractions of uranium ore sand and slime with average diameters dp= 32-460μm(35 to 600 mesh) and densities ρs = 2.58-2.63g/cm3 were fluidized at ambient temperature with water. Bed expansion relation for flui-dization was determined experimentally in the range of voidage ε = 0.530-0.957. The obtained curves for IgRe versus 1 + lgε are all nonlinear. Using two strai-ghtline sections

we approximated the curves

and determined two corresponding terminal velocities vt1 and vt2

and two voidage exponents n1 and n2

as well as bed voidage εc at the intersecting point of the two straight-line sections

the minimum fluidization velocity Umf and the bed voidage εmf at incipient flui-dization for each fraction. By regressive analysis the empirical formulas were obtained for calculating the above fluidization parameters in the range of Archimedes number from 0.6 to 1700. By comparing spherical particles with some non-spherical particles

the fluidization characteristics and relationship for the irregular particles of the uranium ore are discussed.