Abstract: The fluidization characteristics of 16 nm SiO ₂ powder were investigated in a small-scale transparent column. Experiments indicated that agglomerates were formed during fluidization when the gas velocity exceeded the apparent minimum fluidization velocity of the primary particles, which could be smoothly and uniformly fluidized . Surprisingly, in this case the bed expansion was fairly higher than that of Geldart-A particles, and the particulate region was rather broad. With stable,light and large agglomerates, the fluidization behavior was something like that of a liquid-solid fluidized bed.