A method of regenerating an ion exchange resin, comprising the steps of packing
a used ion exchange resin in a regeneration tower; and repeating at least twice
a step comprising passing an aqueous solution of regenerant through the regeneration
tower downward from a top part of the regeneration tower and thereafter passing
ultra-pure water through the regeneration tower upward from a bottom of the regeneration
tower. This method enables regenerating an ion exchange resin efficiently and homogeneously
without mixing of the regenerant into ion exchange resin towers for purification.
