Chemical phosphoric acid production unit provided with a phosphogypsum discharge system

A method for discharging phosphogypsum from a device for receiving phosphogypsum, in a chemical phosphoric acid production unit comprising:

• a reactor for the production of phosphoric acid,
• a receiving device for receiving phosphogypsum obtained after filtration of phosphoric acid produced in the reactor,
• a discharge system for discharging phosphogypsum from the receiving device,
• the discharge system comprising:
• a chute of which the inlet is located inside the receiving device and is arranged so as to communicate with said receiving device;
• and
• a flap moveable around an axis of rotation, said flap being able to open according to a predetermined angle corresponding to a predetermined section for the passage of a fraction of phosphogypsum through the inlet of the chute, and to close in order to prevent the passage of phosphogypsum into the chute;
• the method comprising:
• a step of opening the flap accessing the chute according to a predetermined angle;
• and
• a step of circulating a fraction of phosphogypsum from the receiving device into the chute.