Reclamation and reuse of spent sodium hydroxide in the regeneration of anion resin in demineraliser water treatment plant

摘要

The invention pertains to conventional demineraliser water treatment plants in thermal power stations and other industries. Conventionally the spent sodium hydroxide for the regeneration of exhausted anion resin in such water treatment plants is totally lost and is not reclaimed. The anion exchangers are regenerated by first treating with NaCl and then with NaOH. The spent regenerant may be electrolysed to convert its sodium salts back to NaOH, extra NaOH may be added or the regenerant simply reused without any such restorative treatment. The NaCl may contain HCl and this mixture may also be used to regenerate the cation exchangers.