This invention relates to a process for carrying out an ion exchange process which involves providing two interacting sets of banks of continuously stirred tank reactors (CSTR's) each containing a bed of ion exchange resin and causing the resin to move in one direction through each bank of reactors and the feed solution and/or or eluant in the opposite direction, in carrying out the process, a feed solution is introduced in a first reactor causing dissolved ions to be captured on the resin, eluant is introduced into a reactor upstream of the first reactor in the direction of resin movement causing ions captured on the resin to be removed into the eluant and eluant rich in ions removed from the resin will be taken from a reactor upstream of the reactor in which the eluant was introduced, for further processing. Thus, in this form of the invention there is, in effect, a loading bank of reactors in which ions from the feed solution are captured followed by a regenerating bank of reactors in which the eluant removes the ions captured on the resin and regenerates the resin.