Demineralizers
Demineralizers are ion-exchange-based water treatment units designed to remove dissolved mineral ions from feedwater to produce demineralized water. In a typical ion-exchange demineralizer, a cation exchange resin removes multivalent and monovalent cations (such as Ca2+, Mg2+, Na+, Fe2+) in exchange for hydrogen ions, while an anion exchange resin removes anions (such as Cl-, SO4 2-, HCO3-) in exchange for hydroxide ions. The exchanged H+ and OH- combine to form water, yielding very low-mineral water. Mixed-bed demineralizers combine cation and anion resins in a single bed for polishing to very low conductivity.
Typical configuration uses a sequence of vessels: a cation bed followed by an anion bed; a polishing
Applications and considerations: Demineralizers are used to supply boiler feedwater, process water in electronics and pharmaceuticals,