US4397719A
Expired / Lapsed
US
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Process for preparing nitrogen by ammonium nitrate decomposition
Assignee: Asahi Kasei Corp
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Filing: 1981-09-14
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Granted: 1983-08-09
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Expires: 2001-09-14
Abstract
Abstract Nitrates, such as alkali metal nitrates and ammonium nitrate, are electrolytically reduced to the corresponding nitrites by a process wherein an aqueous solution containing a nitrate is supplied into a cathode chamber of an electrolytic cell including cathode and anode chambers separated by a cation exchange membrane and an electric current is applied to the electrolytic cell, while maintaining the pH of the aqueous solution at a value of at least about 4. This process can be advantageously applied not only to the manufacture of nitrites but, also, to the treatment of waste nitrates. In the treatment of waste ammonium nitrate, the ammonium nitrite so formed is conveniently further treated by subjecting the electrolytically reduced catholyte to thermal decomposition outside the electrolytic cell, and removing the so formed nitrogen and water from the reaction system.
Inventors
- 👤 Mitsuo Yoshida
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 11:23
CPC Classifications
C; C01; C01B; C01B21/00; C01B21/20; C01B21/50; C25; C25B; C25B1/00; C25B1/01; C25B1/14; C02; C02F; C02F1/00; C02F1/46; C02F1/461; C02F1/467; C02F1/4676; C02F1/46104; C02F1/46109; C02F2001/46133; C02F2101/00; C02F2101/10; C02F2101/16; C02F2101/163; C02F2201/00; C02F2201/46; C02F2201/461; C02F2201/46105; C02F2201/46115
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
77 words
A process for the decomposition of ammonium nitrate, comprising supplying an aqueous solution containing ammonium nitrate as a catholyte into a cathode chamber of an electrolytic cell including cathode and anode chambers separated by a cation exchange membrane, subjecting the solution to electrolytic reduction while maintaining the pH of the solution at a value above about 4, thermally decomposing the electrolytically reduced catholyte outside the electrolytic cell and removing formed nitrogen and water from the reaction system.
Claim 2
Dependent Claim
77 words
A process for the decomposition of ammonium nitrate, comprising supplying an aqueous solution containing ammonium nitrate as a catholyte into a cathode chamber of an electrolytic cell including cathode and anode chambers separated by a cation exchange membrane, subjecting the solution to electrolytic reduction while maintaining the pH of the solution at a value above about 4, thermally decomposing the electrolytically reduced catholyte outside the electrolytic cell and removing formed nitrogen and water from the reaction system.
Claim 3
Dependent Claim
30 words
A process for the decomposition of ammonium nitrate according to claim 1, wherein the residual solution left after removal of formed nitrogen and water is recycled to the electrolytic cell.
Claim 4
Dependent Claim
34 words
A process for the decomposition of ammonium nitrate according to claim 1, wherein the pH value of the catholyte is adjusted to a value not higher than about 9 prior to the thermal decomposition.
Claim 5
Dependent Claim
31 words
A process for the decomposition of ammonium nitrate according to claim 1, wherein the thermal decomposition is carried out at a temperature higher than the temperature adopted for the electrolytic reduction.
Claim 6
Dependent Claim
49 words
A process for the decomposition of ammonium nitrate according to claim 1, wherein the thermal decomposition is carried out in the presence of at least one catalyst selected from the group consisting of platinum group metals, active carbon, activated alumina and alumina silicate, thereby to promote the thermal decomposition.
Claim 7
Dependent Claim
59 words
A process for the decomposition of ammonium nitrate according to claim 1, wherein prior to supply of the aqueous solution containing ammonium nitrate to the electrolytic cell, the pH value of the aqueous solution is adjusted so that metal compounds and other impurities contained in the aqueous solution are precipitated, and said impurities are removed as much as possible.
Claim 8
Dependent Claim
32 words
A process for the decomposition of ammonium nitrate according to claim 6, wherein an ultrafiltration module composed of a synthetic high polymer membrane is used to separate and remove fine colloidal particles.
Claim 9
Dependent Claim
46 words
A process for the decomposition of ammonium nitrate according to claim 1, wherein said electrolytic reduction is carried out at a temperature of from about 15° to about 70° C., and said thermal decomposition is carried out at a temperature of about 70° C. or higher.
Claim 10
Dependent Claim
113 words
A process for the decomposition of ammonium nitrate, comprising supplying an aqueous solution containing ammonium nitrate as a catholyte into a cathode chamber of an electrolytic cell including cathode and anode chambers separated by a cation exchange membrane, subjecting the solution to electrolytic reduction while maintaining the pH of the solution at a value above about 4, thermally decomposing the electrolytically reduced catholyte outside the electrolytic cell, the pH value of said catholyte being adjusted to a value not higher than about 9 prior to the thermal decomposition, removing formed nitrogen and water from the reaction system, and, after removal of formed nitrogen and water, recycling the residual solution to the electrolytic cell.
Claim 11
Dependent Claim
113 words
A process for the decomposition of ammonium nitrate, comprising supplying an aqueous solution containing ammonium nitrate as a catholyte into a cathode chamber of an electrolytic cell including cathode and anode chambers separated by a cation exchange membrane, subjecting the solution to electrolytic reduction while maintaining the pH of the solution at a value above about 4, thermally decomposing the electrolytically reduced catholyte outside the electrolytic cell, the pH value of said catholyte being adjusted to a value not higher than about 9 prior to the thermal decomposition, removing formed nitrogen and water from the reaction system, and, after removal of formed nitrogen and water, recycling the residual solution to the electrolytic cell.
Claim 12
Dependent Claim
31 words
A process for the decomposition of ammonium nitrate according to claim 9, wherein the thermal decomposition is carried out at a temperature higher than the temperature adopted for the electrolytic reduction.
Claim 13
Dependent Claim
49 words
A process for the decomposition of ammonium nitrate according to claim 9, wherein the thermal decomposition is carried out in the presence of at least one catalyst selected from the group consisting of platinum group metals, active carbon, activated alumina and alumina silicate, thereby to promote the thermal decomposition.
Claim 14
Dependent Claim
59 words
A process for the decomposition of ammonium nitrate according to claim 9, wherein prior to supply of the aqueous solution containing ammonium nitrate to the electrolytic cell, the pH value of the aqueous solution is adjusted so that metal compounds and other impurities contained in the aqueous solution are precipitated, and said impurities are removed as much as possible.
Claim 15
Dependent Claim
32 words
A process for the decomposition of ammonium nitrate according to claim 12, wherein an ultrafiltration module composed of a synthetic high polymer membrane is used to separate and remove fine colloidal particles.
Claim 16
Dependent Claim
132 words
A process for the decomposition of ammonium nitrate comprising: adjusting the pH value of an aqueous solution containing ammonium nitrate so that metal compounds and other impurities contained in the aqueous solution are precipitated, and said impurities are removed as much as possible; separating and removing fine colloidal particles by utilizing an ultrafiltration module composed of a synthetic high polymer membrane; supplying the thereby obtained aqueous solution containing ammonium nitrate as a catholyte into a cathode chamber of an electrolytic cell including cathode and anode chambers separated by a cation exchange membrane; subjecting the solution to electrolytic reduction while maintaining the pH of the solution at a value above about 4; and thermally decomposing the electrolytically reduced catholyte outside the electrolytic cell and removing formed nitrogen and water from the reaction system.
Claim 17
Dependent Claim
132 words
A process for the decomposition of ammonium nitrate comprising: adjusting the pH value of an aqueous solution containing ammonium nitrate so that metal compounds and other impurities contained in the aqueous solution are precipitated, and said impurities are removed as much as possible; separating and removing fine colloidal particles by utilizing an ultrafiltration module composed of a synthetic high polymer membrane; supplying the thereby obtained aqueous solution containing ammonium nitrate as a catholyte into a cathode chamber of an electrolytic cell including cathode and anode chambers separated by a cation exchange membrane; subjecting the solution to electrolytic reduction while maintaining the pH of the solution at a value above about 4; and thermally decomposing the electrolytically reduced catholyte outside the electrolytic cell and removing formed nitrogen and water from the reaction system.
Claim 18
Dependent Claim
30 words
A process for the decomposition of ammonium nitrate according to claim 14, wherein the residual solution left after removal of formed nitrogen and water is recycled to the electrolytic cell.
Claim 19
Dependent Claim
34 words
A process for the decomposition of ammonium nitrate according to claim 14, wherein the pH value of the catholyte is adjusted to a value not higher than about 9 prior to the thermal decomposition.
Claim 20
Dependent Claim
31 words
A process for the decomposition of ammonium nitrate according to claim 14, wherein the thermal decomposition is carried out at a temperature higher than the temperature adopted for the electrolytic reduction.
Claim 21
Dependent Claim
49 words
A process for the decomposition of ammonium nitrate according to claim 14, wherein the thermal decomposition is carried out in the presence of at least one catalyst selected from the group consisting of platinum group metals, active carbon, activated alumina and alumina silicate, thereby to promote the thermal decomposition.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-08-08 | 1987-02-07 | 1987-08-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-08-08 | 1991-02-07 | 1991-08-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-08-08 | 1995-02-07 | 1995-08-09 | $7700.00 | Window Closed / Lapsed |