METHOD FOR ZERO-DISCHARGE PHOSPHATIZATION AND SAPONIFICATION BASED ON HIGH-PRESSURE CLOSED CIRCULATION SYSTEM

The invention discloses a method for zero-discharge phosphatization and saponification based on a high-pressure closed circulation system, which comprises an autoclave, a separation kettle, a buffer kettle and a hydraulic pump. The method comprises the following steps: step 1: a workpiece is fed into the autoclave and then sealed such that the pressure range of the autoclave is above 20 MPa; step 2: degreasing and derusting by CO2; step 3: cyclic separation; step 4: high-pressure phosphatization; step 5: cyclic separation II; step 6: high-pressure saponification; step 7: cyclic separation III; and step 8: the autoclave is opened for aeration drying. The technical solution of the present application can greatly reduce the amount of acids, bases and industrial water used, provides good working conditions, facilitates the collection and treatment of production residues, does not produce sewage, does not cause environmental pollution and achieves zero discharge.