Method and apparatus for blending powders in a fluidized bed

Abstract

A mixture of powders, preferably UO.sub.2 powders, is blended to complete homogeneity in a nuclear-safe, bubbling-bed fluidized bed blender. The blender includes a generally vertically-oriented, slab-shaped, nuclear-safe mixing vessel having a fluidizing grid disposed on the bottom of the vessel. The fluidizing grid comprises a linear array of generally downwardly-directed pyramidal-shaped hoppers each having walls converging into a conically-shaped closable opening. A plurality of gas orifices is provided for directing a flow of fluidizing gas downwardly into the bottom of each of the hoppers and fluidizing gas is supplied to the orifices at a velocity sufficient to cause bubbles of fluidizing gas to rise through and emerge from the mixture of UO.sub.2 powders until a homogeneous blend of solid UO.sub.2 powders is achieved. The apparatus eliminates dead-zones normally present near the bottom of prior art fluidized bed blenders. A method is also disclosed of blending a mixture of powders which in a preferred application is a mixture of UO.sub.2 powders.

Dependencies are inferred from the claim text.