System for regulating and controlling pH of effluent of chemical crystallization granulation fluidized bed by using CO2

The invention provides a system for regulating and controlling pH of effluent of a chemical crystallization granulation fluidized bed by using CO2, which comprises a chemical crystallization granulation fluidized bed unit, a CO2 adding unit, a CO2 pressurizing and dissolving unit and a carbonic acid adding unit, the other end of the CO2 gas conveying pipe is communicated with a gas inlet pipe in the CO2 pressurizing and dissolving unit; the dissolving water inlet pipe is communicated with the fluidized bed water inlet pipe, and the dissolving water outlet pipe is communicated with a feed port of a jet device in the carbonic acid adding unit; and a tubular static mixer is arranged on the fluidized bed water outlet pipe at the downstream of the jet device. Compared with the prior art that inorganic acid is added to adjust the pH value of the effluent of the fluidized bed, the system has the advantages that the adjusting effect is stable, the safety is high, anions which have additional influence on the environm