Several theories and methods for particulatization of aggregative fluidization have been proposed, including particle design (size, density, shape, surface structure, extraneous particles), external force field design (axial uniform magnetic field, transverse rotating magnetic field), reactor internals and configuration design (ring-shaped internals, fan-shaped internals, floating balls, internal and external circulating fluidizing beds), and fluid design (density, viscosity, supercritical CO2). Experimental results showed that the above theories and methods have been effective in restraining or suppressing the formation of bubbles and agglomerates, and in changing gas-solids fluidization from aggregative to particulate. In addition, methods and indices for evaluating the quality of fluidization have been established, and several instruments have been developed. (C) 2003 Published by Elsevier B.V.