Abstract: An apparatus for mixing and dispensing solid materials stored in bulk, which have poor flow characteristics, includes a container or hopper having two, opposite walls which are inclined, for example at angles in the range of from about 20 to about 70 degrees to the horizontal. The hopper has two walls which are vertical. The hopper is provided on its inside with at least two rotary screw conveyors with opposite directional material moving effects. For example, at least one extraction screw conveyor and at least one auxiliary screw conveyor is provided so as to simultaneously generate an upward and a downward movement in the mass of solid, bulk material in the hopper during the extraction operation. The apparatus is particularly useful in extracting, mixing and dispensing powdered, fibrous, aggregate, granular materials, miscellaneous pieces of bulk material scrap and the like without formation of gaps or bridges of material within the hopper.