Sand-gravel material processing system

The utility model relates to a sandstone material processing system. Stock bin, the device is characterized in that a coarse crushing device is arranged below the stock bin; the coarse crushing deviceis matched with the first screening device; a medium fine crushing device is arranged behind the first screening device; the medium fine crushing device is matched with the second screening device; an ultrafine crushing device is arranged behind the second screening device; an outlet of the ultrafine crushing device is connected with an impurity separation mechanism; the impurity separation mechanism comprises a screening shell; end covers are arranged at the two ends of the screening shell, a material inlet is formed in the upper portion of one end of the screening shell, a material outlet is formed in the lower portion of the other end of the screening shell, a stirring shaft is arranged in the screening shell and provided with spiral blades, the stirring shaft is driven by a gear motor, meshes are formed in th