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.