| 摘要 |
PROBLEM TO BE SOLVED: To provide a crystallization reactor recovering a hardly soluble salt at high recovery rate without increasing a supply amount of seed crystals.SOLUTION: This crystallization reactor includes a crystallization reaction tank 10 having a crystallization reaction part 28 adding a calcium preparation to raw water containing a crystallization objective substance to generate crystals of the hardly soluble salt. In the crystallization reaction tank 10, there is disposed an inner circumferential wall 26 facing to the outer circumferential wall of the crystallization reaction tank 10, and there is provided a solid-liquid separation part 30 forming an upward flow between the inner circumferential wall and the outer circumferential wall, and performing solid-liquid separation between the crystals and treatment water. A valve 18 provided in a raw water conduction line 16 is opened such that the water conduction time of the raw water into the crystallization reaction tank 10 becomes 1 time or above and 2 times or below a residence time in the solid-liquid separation part 30, and the valve 18 provided in the raw water conduction line 16 is closed such that the water conduction stop time of the raw water into the crystallization reaction tank 10 becomes a time of 1/4 times or above and 1/2 times or below the residence time in the solid-liquid separation part 30 after the raw water conduction. |
