Fluidized bed systems for segregating cleaning or classifying particulate matter of differing physical properties such as particle density or size. Multiple stage beds preferably operate in a partially fluidized state and the classification structure provides for full peripheral discharge of both floats from the upper portion of each bed and sinks from the lower portion of each bed to alleviate the tendency of fluidized medium to both short circuit the particles of the upper stage and restrict the flow of particles from the upper stage to the lower stage.
