Abstract: A plate blender for use in the blending of particulate and granular solid materials is disclosed. The plate blender includes a tank having a plurality of vertical, radially extending baffles and with a series of vertically spaced windows in some of the baffles. In one embodiment, one of the baffles is of solid construction and the remaining baffles have a series of vertically spaced windows in each baffle, with the series of windows for each successive baffle in the direction of filling of the vessel being located at a progressively lower level than for the previous baffle so that the filling sequence results in the material to be blended being allowed to flow successively from one blending zone to the next around the circumference of the vessel and with the location and number of windows providing for consecutive layers of material throughout the zones. The plate blender may be employed in the blending of flowable particulate solid materials such as plastic pellets and powders.