An apparatus and process produces salts by an electrodialysis operation.
The basic electrodialysis apparatus is a cell having a number of
compartments separated by membranes. A DC source is connected to drive a
current through a feed stream passing through the cell which splits the
salt stream into an acid and a base. The incoming feed may be nanofiltered
to remove divalent metal. The base loop may be in communication with an
ion exchange column packed with a material that removes multivalent
cations. Depending upon the material being processed and the desired end
result either or both the nanofiltration and the ion exchanged column may
be used in the apparatus.