procedures for the sharing of verduennten waesserigen salzloesungen in a more concentrated salzloesung and water by means of ionenaustausches

摘要

An anion and a cation exchanger are used in series in any preferred order, are regenerated after exhaustion, and reused. Before regeneration, one of the exhausted ion exchangers is pretreated with the used regenerating solution of the other ion exchanger, until the ions removed from the separated solution of the first ion exchanger have been substantially completely replaced by the homologous ions of the pretreatment solution. In the course of this, a more concentrated salt solution than originally introduced is formed in the separated solution, and subsequently reactivates the same ion exchanger with the corresponding regenerating solution, forming a salt solution of the regenerating materials. Salts in dilute solution are to a large extend separated from salt obtained from regenerating materials. This is advantageous when acids and bases are used for regeneration, which mutually form a valuable salt. A second advantage is the concentration of the salts originally present in the dilute solution. These advantages reduce the desalination costs, and make economic recovery of water from such solution possible. Desalination of natural waters with a salt content exceeding 20 gm-equiv./m3 and effluents, particularly from industrial operations.