Demineralization systems are mainly referring to ion exchange (IX) technology. Typically this process is used for the removal of dissolved solids to produce water at a very high purity. Typical uses of this technology are in the purification of water required in the production of semiconductors and solar panels (ultrapure water for rinsing), power (condensate polishing, boiler feed water) and steam production (condensate polishing, boiler feed water).
Ion exchange is a reversible interchange of ions between a resin (ion exchange material) and a liquid in which there is no permanent change in the structure of the resin. An ion is an atom or group of atoms with an electric charge. Positive-charged ions are called Cations and are usually metals. Negative-charged ions are called Anions and are usually non-metals.
The impurity ions (positive and/or negative-charged) are taken up by the resin, which must be periodically regenerated to restore it to the original ionic form and depending on the application, there are two types of regeneration method, namely internal and external. Internal regeneration is referred to when regenerate the resins takes place within the vessel and external regeneration, which is more complicated, is referred to when regeneration takes place outside of vessel used for purification where the resin is transferred to a regeneration vessel, regenerated and then returned to the operating vessel.
