Multi-stage impurity removing and refining method in production process of secondary aluminum

The invention relates to a multi-stage impurity removing and refining method in the production process of secondary aluminum. The method comprises the following steps of: (1) pretreating, wherein pure aluminum scraps are obtained for standby; (2) removing paint; (3) preparing material; (4) drying; (5) melting; (6) mixed melting; (7) refining, degassing and deslagging; (8) adjusting components; (9) re-degassing until pinholes are qualified, standing, and removing hydrogen in the melt thoroughly; and (10) when the temperature reaches 680-720 DEG C, casting cast ingots of the secondary aluminum product. According to the method, physical and chemical methods are integrated, from screening in the pretreating process and drying and preheating for removing dirt, corrosion and oils on the surface of the waste aluminum, to the melting process and refining process for removing inserts in the waste aluminum parts, a rare earth type modifier is used, so that not only the mechanical property of aluminum melt can be improv