US3901781A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for demineralizing water
Assignee: Consiglio Nazionale delle Richerche
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Filing: 1973-07-20
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Granted: 1975-08-26
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Expires: 1993-07-20
Abstract
Abstract A process for demineralizing water comprising the combination of a pre-treatment of the water and an electrodialysis process for demineralizing said pre-treated water, said pre-treatment comprising an ion exchange treatment using exchange resins of cationic type to replace in the water to be fed to the electrodialysis device, the hard cations with H ions and Na ions, either separately or together, according to the water characteristics, in particular using H ions to neutralize the HCO3 ions, said pre-treatment also comprising a regeneration of the exhausted ion exchange resins.
Inventors
- 👤 Roberto Passino
- 👤 Gianfranco Boari
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 12:09
CPC Classifications
B; B01; B01D; B01D61/00; B01D61/42; B01D61/44; C; C02; C02F; C02F1/00; C02F1/46; C02F1/469; C02F1/4693; B01D2311/00; B01D2311/26; B01D2311/2623; C02F1/42; Y; Y02; Y02A; Y02A20/00; Y02A20/124
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
76 words
A PROCESS FOR DEMINERALIZING WATER COMPRISING THE COMBINATION OF A PRE-TREATMENT OF THE WATER AND AN ELECTRODIALYSIS PROCESS FOR DEMINERALIZING SAID PRE-TREATED WATER, SAID PRETREATMENT COMPRISING AN ION EXCHANGE TREATMENT USING EXCHANGE RESINS OF CATIONIC TYPE TO REPLACE IN THE WATER TO BE FED TO THE ELECTRO-DIALYSIS DEVICE, THE HARD CATIONS WITH H+ IONS AND NA+ IONS, USING H+ IONS TO NUETRALIZE THE HCO3-IONS, SAID PRE-TREATMENT ALSO COMPRISING A REGENERATION OF THE EXHAUSTED ION EXCHANGE RESINS.
Claim 2
Dependent Claim
76 words
A PROCESS FOR DEMINERALIZING WATER COMPRISING THE COMBINATION OF A PRE-TREATMENT OF THE WATER AND AN ELECTRODIALYSIS PROCESS FOR DEMINERALIZING SAID PRE-TREATED WATER, SAID PRETREATMENT COMPRISING AN ION EXCHANGE TREATMENT USING EXCHANGE RESINS OF CATIONIC TYPE TO REPLACE IN THE WATER TO BE FED TO THE ELECTRO-DIALYSIS DEVICE, THE HARD CATIONS WITH H+ IONS AND NA+ IONS, USING H+ IONS TO NUETRALIZE THE HCO3-IONS, SAID PRE-TREATMENT ALSO COMPRISING A REGENERATION OF THE EXHAUSTED ION EXCHANGE RESINS.
Claim 3
Dependent Claim
34 words
A process according to claim 1, wherein the ion exchange treatment provides to use cation exchange resins in R.Na form to partially replace cations in the water with other cations of higher transport number.
Claim 4
Dependent Claim
31 words
A process according to claim 1, wherein said cation resins are partially regenerated in the R.Na form by passing brine exhausted from a demineralization plant through the bed of exhausted resins.
Claim 5
Dependent Claim
18 words
A process according to claim 3, wherein the brine is that which is exhausted from the electro-dialysis plant.
Claim 6
Dependent Claim
36 words
A process according to claim 1, wherein the cation exchange resins are at least partially regenerated in the R.H form by passing an acid, as the sulphuric acid, through the bed of the exhausted exchange resins.
Claim 7
Dependent Claim
111 words
A process for demineralizing water which comprises the steps of: a. subjecting feed water containing hard cations and HCO3 ions to pretreatment involving degassing by contacting same with ion exchange resins of R.Na and R.H type according to the following reactions: 2R.Na + Ca -> R2.CA + 2Na 2R.H + Ca -> R2.Ca + 2H 2H + 2HCO3 -> 2H2O + 2CO2 b. subjecting pretreated water obtained from step (a) to electrodialysis to recover demineralized water and concentrated salt solution; c. regenerating the R.Na type ion exchange resin at least in part with the concentrated salt solution of step (b); d. regenerating the R.H type ion exchange resin with an acid.
Claim 8
Dependent Claim
111 words
A process for demineralizing water which comprises the steps of: a. subjecting feed water containing hard cations and HCO3 ions to pretreatment involving degassing by contacting same with ion exchange resins of R.Na and R.H type according to the following reactions: 2R.Na + Ca -> R2.CA + 2Na 2R.H + Ca -> R2.Ca + 2H 2H + 2HCO3 -> 2H2O + 2CO2 b. subjecting pretreated water obtained from step (a) to electrodialysis to recover demineralized water and concentrated salt solution; c. regenerating the R.Na type ion exchange resin at least in part with the concentrated salt solution of step (b); d. regenerating the R.H type ion exchange resin with an acid.
References Cited (Backward Citations)
US3063924A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-08-25 | 1979-02-24 | 1979-08-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-08-25 | 1983-02-24 | 1983-08-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-08-25 | 1987-02-24 | 1987-08-26 | $7700.00 | Window Closed / Lapsed |