Classification sand mill and operation method thereof

The invention discloses a grading sand mill, which relates to the technical field of sand mills and comprises a machine body, a grinding assembly, a grading discharging assembly, a driving motor and a sliding assembly. The invention further discloses an operation method of the grading sand mill. The operation method comprises the following steps of feeding, material grinding, grading discharging and excess material discharging. The grinding assembly is arranged in the machine body, materials can move in the grinding assembly from top to bottom, the materials can be ground in the moving process, when the materials circulate to the bottom of the device, the materials meeting the grinding standard are screened through the grading discharging assembly and then discharged, and therefore grading discharging of the materials is achieved; materials which do not reach the grinding standard are recycled into the grinding assembly under the action of the inclined groove and continue to be ground, in the process, dischar