Continuous countercurrent ion exchange process

Claim 1

A process for absorbing ions of interest onto ion exchange resin particles from a feed liquor containing ions which when absorbed on said resin particles cause the density of the particles to increase, comprising the steps of continously flowing the feed liquor upwardly through a main bed of ion exchange resin particles contained in a main chamber of an absorption column and thereby maintaining the bed in a fluidized state, the resin being one on which the ions of interest are preferentially absorbed onto the resin particles causing the density of the loaded resin particles to increase and migrate toward the lower region of said column, continuously collecting loaded particles from the lower region of the column, normally passing an outflow of the feed liquor from the upper region of the main chamber upwardly into the lower region of a polishing chamber containing a secondary polishing bed consisting of a batch of predetermined size of fluidized ion exchange resin particles whereby residual ions of interest in said outflow from the main bed are substantially completely absorbed onto the resin particles in the polishing bed, thereby producing a barren liquor flowing out of the upper region of the polishing chamber, the batch of resin particles contained in the main chamber corresponding in volume to between about four to about twenty of the batches of particles contained in the polishing chamber, periodically diverting the outflow of the feed liquor from the upper region of the main chamber to an auxiliary outlet, transferring the batch of resin particles from the polishing chamber to the main chamber while maintaining the flow of feed liquor upwardly through the main chamber to maintain the particles fluidized therein, replenishing the polishing chamber by introducing into it a fresh batch of particles, and thereafter recommencing the outflow of the feed liquor from the upper region of the main bed upwardly into the lower region of the polishing chamber.