Patent US1804731A successfully refreshed from Google Patents.
Patent US4294815A successfully refreshed from Google Patents.
US4294815A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process of producing chlorine dioxide and, if desired, chlorine
Assignee: GEA Group AG
•
Filing: 1979-11-13
•
Granted: 1981-10-13
•
Expires: 1999-11-13
Abstract
Abstract A process for the production of chlorine dioxide by membrane electrolysis of aqueous sodium chloride, reaction of hydrogen and chlorine so-formed to form hydrogen chloride and reaction of the so-formed hydrogen chloride with the sodium chlorate also formed by the electrolysis to form chlorine dioxide is disclosed. Also disclosed is the production of chlorine by such a process.
Inventors
- 👤 Karl Lohrberg
- 👤 Siegfried Bielz
- 👤 Paul Janisch
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 02:01
CPC Classifications
B; B01; B01J; B01J19/00; B01J19/24; B01J19/2455; B01J19/2465; B01J19/2475; C; C01; C01B; C01B11/00; C01B11/02; C01B11/022; C01B11/023; C01B11/025
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
127 words
A process for producing ClO 2 which comprises (A) feeding aqueous NaCl into an electrolyte membrane cell and therein electrolyzing the same to obtain H 2 Cl 2 , NACH (B) reacting the H 2 and Cl 2 formed in step A to form HCl; (C) feeding HCl from step B into a chlorate reaction zone; (D) feeding NaClO 3 into said chlorate reaction zone, with NaClO 3 being obtained as a product of an electrolysis of NaCl; (E) reacting sodium chlorate with hydrochloric acid in said chlorate reaction zone to form chlorine dioxide chlorine and sodium chloride; (F) separating said ClO 2 and Cl 2 from NaCl and electrolyzing said NaCl in an electrolysis cell to obtain NaClO 3 and recycling the same to step D.
Claim 2
Dependent Claim
127 words
A process for producing ClO 2 which comprises (A) feeding aqueous NaCl into an electrolyte membrane cell and therein electrolyzing the same to obtain H 2 Cl 2 , NACH (B) reacting the H 2 and Cl 2 formed in step A to form HCl; (C) feeding HCl from step B into a chlorate reaction zone; (D) feeding NaClO 3 into said chlorate reaction zone, with NaClO 3 being obtained as a product of an electrolysis of NaCl; (E) reacting sodium chlorate with hydrochloric acid in said chlorate reaction zone to form chlorine dioxide chlorine and sodium chloride; (F) separating said ClO 2 and Cl 2 from NaCl and electrolyzing said NaCl in an electrolysis cell to obtain NaClO 3 and recycling the same to step D.
Claim 3
Dependent Claim
61 words
A process according to claim 1, wherein the mixed gases which become available as a result of the reaction of chlorate in step E are scrubbed and the resulting chlorine gas together with hydrogen, at least part of which comes from the membrane cell used in step A, is fed to the combustion stage of step B for producing hydrogen chloride.
Claim 4
Dependent Claim
40 words
A process according to claim 1 wherein the mixed gases which become available as a result of the reaction of chlorate in step E are scrubbed and the resulting chlorine gas is introduced into alkaline solution to form alkali hypochlorite.
Claim 5
Dependent Claim
113 words
A process according to claim 1, wherein at least a partial stream of the anolyte withdrawn from the membrane cell employed in step A is strenghtened with alkali halide, precipitates are removed and the so-strengthened anolyte is then adjusted to a pH value below 1 at elevated temperature in a decomposer thereby decomposing chlorate in said anolyte to form chlorine and chlorine dioxide gases, the resulting chlorine gas is fed to the combustion stage of step B for the production of hydrogen chloride, and the alkali halide solution is adjusted to a higher pH value in range of 1 to 6 before it is recycled to the anode chamber of the membrane cell.
Claim 6
Dependent Claim
18 words
A process according to claim 4 wherein said alkali halide solution is adjusted to pH 1 to 2.5.
Claim 7
Dependent Claim
63 words
A process according to claim 4 wherein a partial stream amounting to at least 20 percent of the anolyte withdrawn from the membrane cell is formed and is adjusted to a pH value below 1.0 and is subsequently re-united with the main stream of said anolyte to form a re-united stream having a desired pH value in the range of 1.0 to 6.0.
Claim 8
Dependent Claim
15 words
A process according to claim 6 wherein said anolyte is adjusted to pH below 0.8.
Claim 9
Dependent Claim
24 words
A process according to claim 6 wherein said partial stream amounts to 8 to 15 percent of the anolyte withdrawn from said membrane cell.
Claim 10
Dependent Claim
47 words
A process according to claim 1 wherein hydrochloric acid is added to a partial stream of the anolyte withdrawn from the membrane cell and the resulting mixed gases are united with the mixed gases which have become available in the chlorate decomposer of steps D and E.
Claim 11
Dependent Claim
24 words
A process according to claim 4 wherein anolyte is withdrawn from the membrane cell is fed to the decomposition of chlorate in the decomposer.
Claim 12
Dependent Claim
26 words
A process according to claim 4, wherein the ClO 2 decomposition product of said sodium chlorate is mixed with the chlorine dioxide obtained from step E.
Claim 13
Dependent Claim
32 words
A process according to claim 1, wherein all of the HCl used for the NaClO 3 reaction comes from reaction of hydrogen and chlorine which is given off by the membrane cell.
Claim 14
Dependent Claim
57 words
A process according to claim 1, wherein at least a major part of hydrogen chloride in a quantity which is at least a major part of the equivalent of the chlorine dioxide is produced by burning of chlorine gas with hydrogen, said chlorine gas being taken from the electrolysis of alkali metal chloride in a membrane cell.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-10-12 | 1985-04-13 | 1985-10-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-10-12 | 1989-04-13 | 1989-10-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-10-12 | 1993-04-13 | 1993-10-13 | $7700.00 | Window Closed / Lapsed |