From the perspective of mechanical structural principle, the frequency conversion vibration feeding system is the primary control unit. Adjustable low-frequency vibration (15-25Hz) eliminates material bridging and particle agglomeration of wet corn and mixed soil blocks, making mixed materials present discrete single-particle falling state. This structural design eliminates turbulent material flow, guarantees constant vertical falling speed of corn particles and impurity particles, and lays a foundation for stable density sorting. The core separation chamber cancels turbulent air duct design of old equipment, and adopts closed-loop circulating axial airflow system with constant wind pressure. The system fixes horizontal airflow velocity at 0.3m/s to match the buoyancy demand of qualified corn kernels, avoiding two common technical drawbacks: lightweight corn being sucked into sediment area and tiny fine sand being wrapped into finished corn materials.