Low-temperature crystallizer

The utility model discloses a low-temperature crystallizer, and relates to the technical field of wastewater treatment. The device comprises a drying box, the drying box is communicated with a connecting pipe, a feeding pipe and a discharging pipe, and the free end of the connecting pipe is communicated with a low-temperature crystallizer; the fixed frame is movably arranged in the drying box, a conical blocking net is arranged on the fixed frame, and a drying agent is put on the blocking net through the feeding pipe; and the blocking piece is arranged in the drying box and used for automatically blocking the feeding pipe. When the drying device is used, water vapor generated by the low-temperature crystallizer enters the drying box through the connecting pipe, the fixing frame is driven by the driving piece to do linear reciprocating motion in the vertical direction, the blocking net is driven to move along with the fixing frame, a drying agent on the blocking net is always in a moving state, the contact are