초록 ▼

A method of reclaiming spent aqueous brine solutions used in the regeneration of water-softening resins. An aqueous solution chloride or other brine is acidified with HCl to a pH of between about 0.5 and 6 and a soluble sulfate salt, preferably Na.sub.2 SO.sub.4 is added, together with a precipitati

A method of reclaiming spent aqueous brine solutions used in the regeneration of water-softening resins. An aqueous solution chloride or other brine is acidified with HCl to a pH of between about 0.5 and 6 and a soluble sulfate salt, preferably Na.sub.2 SO.sub.4 is added, together with a precipitation inhibitor of the type polyacrylamide. Following such treatment, the spent brine is pumped at high pressure axially through a spirally-wound nanofiltration-type membrane device which is effective to remove at least about 90% of the divalent hardness while allowing passage therethrough of at least about 90% of the monovalent cations. As a result of such treatment, about 90 to 95% of the volume of spent brine can be efficiently and effectively reclaimed in a form in which it is suitable for use again in regenerating water-softening resins or the like.

대표청구항 ▼

[ What is claimed is:] [1.] A method of reclaiming an aqueous brine solution used in the regeneration of water-softening resins, which method comprises the steps of:(a) treating an aqueous NaCl or KCl brine solution that contains significant amounts of divalent cations, by adding (i) a soluble sulfa

[ What is claimed is:] [1.] A method of reclaiming an aqueous brine solution used in the regeneration of water-softening resins, which method comprises the steps of:(a) treating an aqueous NaCl or KCl brine solution that contains significant amounts of divalent cations, by adding (i) a soluble sulfate salt, (ii) with an acid selected from the group consisting of hydrochloric, sulfuric, nitric and phosphoric to lower the pH to about 0.5 and about 6, and (iii) a precipitation inhibitor selected from the group consisting of polyacrylic acid, polyacrylamide and polymalic acid;(b) applying said treated brine from step (a) to semipermeable membrane material which permits the passage therethrough of at least about 90% of monovalent ions in said solution while rejecting at least about 90% of all divalent cations in said aqueous solution; and(c) recovering the permeate from step (b) for use in regenerating water-softening resins.