COUNTERCURRENT ION EXCHANGE DEVICE USING RESIN OF UNIFORM PARTICLE DIAMETER AND REGENERATION OF ION EXCHANGE RESIN

PROBLEM TO BE SOLVED: To provide a countercurrnet ion exchange device capable of efficiently regenerating an ion exchange resin while maintaining the advantages of the countercurrent ion exchange device as well as a method for regenerating the ion exchange resin. SOLUTION: This countercurrent ion exchange device consists of a pair of water collecting devices at the upper part and the lower part of a resin tower. In addition, on the upper part of the lower water collecting device 2, a packed part 4 containing an ion exchange resin, a packed part 6 containing an inactive resin with a specific gravity less than 1 through a free board part 5 equivalent to 2-15% of the height of an ion exchange resin layer and the upper water collecting device 3 are arranged sequentially. On the other hand, the lower water collecting device 2 has a connection with a water collecting and distributing pipe with a treated water outflow valve 9 and a back wash water inflow valve 10. Further, the upper water collecting device 3 has a connection with a water collecting and distributing pipe with an untreated water inflow valve 7 and a regenerated drain outflow valve 8. Besides, the ion exchange resin to be packed in the ion exchange resin layer is of a uniform particle diameter containing at least 85%, of the total amount of particles, present in the range of particle diameters of ±0.15mm of an average particle diameter. The average particle diameters of this particle are preferably 0.4-0.8mm.