Patent US2658874A successfully refreshed from Google Patents.
US4218293A
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Electrochemical apparatus and process for manufacturing halates
Assignee: Occidental Chemical Corp
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Filing: 1979-02-02
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Granted: 1980-08-19
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Expires: 1999-02-02
Abstract
Abstract An apparatus for the manufacture of halate, such as sodium chlorate, includes an electrolytic cell having a plurality of anodes and cathodes, clearance passageways between which have electrolyte, hypohalite and gaseous electrolysis product, principally hydrogen, moving upwardly between them, an enclosure covering the tops of at least four such passageways and narrowing down to a passageway extending upwardly from the top of the enclosure and a downward passage for circulation of electrolyte which includes an upper baffled portion and a lower unbaffled portion, the unbaffled part being alongside the electrodes and extending to the bottom of the cell, from which electrolyte is drawn upwardly past the electrodes. Natural circulation due to gravity flow and density differences between the liquid electrolyte and that entrained in gas or having gas entrained in it is normally sufficient so that stirring or pumping means are not required. The invention provides a means for converting higher current density cells to lower current density cells so as to be more energy efficient. In such conversions additional anode-cathode units are installed between those already in place and gases generated from them are collected with gases generated from an adjacent originally present anode-cathode unit and are moved upwardly with entrained liquid through previously existing passages while other circulating electrolyte is moved downwardly, also through previously existing passageways, baffled and unbaffled. Other aspects of the invention relate to particular types of spacers between electrodes and to more energy efficient lower current density electrochemical processes for manufacturing sodium chlorate.
Inventors
- 👤 Chester R. Nawrot
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 23:04
CPC Classifications
C; C25; C25B; C25B1/00; C25B1/01; C25B1/24; C25B1/26; C25B1/265; C25B9/00; C25B9/13; C25B9/17; Y; Y02; Y02P; Y02P20/00; Y02P20/10
Claims Analysis
Total Claims: 30
Claim 1
Independent Claim
294 words
An apparatus for the manufacture of a halate which comprises an electrolytic cell including a plurality of monopolar dimensionally stable anodes and cathodes in spaced and paired relationship with one another, said anodes being holdable to the cell at a side thereof and being removable from the cell through a side thereof, means for applying positive and negative electrical potentials to the anodes and cathodes, respectively, and means for moving electrolyte in the cell so that it conducts current between the anodes and the cathodes of the anode-cathode pairs, passes between the anodes and cathodes of the pairs and is at least partially electrolyzed thereby to hypohalite and gaseous electrolysis product, which means for moving the electrolyte include clearance passageways between anodes and cathodes of the pairs for conducting such hypohalite, electrolyte and gaseous electrolysis product upwardly, an enclosure covering the tops of at least four such passageways between anode and cathode pairs and narrowing down to a passageway less than 1/10 the horizontal cross-sectional area of such enclosure and extending upwardly from it to an upper part of the cell, which enclosure and upwardly extending passageway guide gas and liquid moving upwardly from the clearance passageways, and a passage to conduct hypohalite downwardly past baffles to a lower portion of the cell, said passage containing said hypohalite for a long enough period of time during operation of the cell to convert a substantial proportion thereof to halate, means for withdrawing halate-containing liquor from the cell after it has descended through the baffled passage to the lower portion of the cell, means for feeding halide to the cell to replace that consumed in the preparation of withdrawn halate and means for withdrawing a gaseous product of electrolysis from the upper part of the cell.
Claim 2
Independent Claim
294 words
An apparatus for the manufacture of a halate which comprises an electrolytic cell including a plurality of monopolar dimensionally stable anodes and cathodes in spaced and paired relationship with one another, said anodes being holdable to the cell at a side thereof and being removable from the cell through a side thereof, means for applying positive and negative electrical potentials to the anodes and cathodes, respectively, and means for moving electrolyte in the cell so that it conducts current between the anodes and the cathodes of the anode-cathode pairs, passes between the anodes and cathodes of the pairs and is at least partially electrolyzed thereby to hypohalite and gaseous electrolysis product, which means for moving the electrolyte include clearance passageways between anodes and cathodes of the pairs for conducting such hypohalite, electrolyte and gaseous electrolysis product upwardly, an enclosure covering the tops of at least four such passageways between anode and cathode pairs and narrowing down to a passageway less than 1/10 the horizontal cross-sectional area of such enclosure and extending upwardly from it to an upper part of the cell, which enclosure and upwardly extending passageway guide gas and liquid moving upwardly from the clearance passageways, and a passage to conduct hypohalite downwardly past baffles to a lower portion of the cell, said passage containing said hypohalite for a long enough period of time during operation of the cell to convert a substantial proportion thereof to halate, means for withdrawing halate-containing liquor from the cell after it has descended through the baffled passage to the lower portion of the cell, means for feeding halide to the cell to replace that consumed in the preparation of withdrawn halate and means for withdrawing a gaseous product of electrolysis from the upper part of the cell.
Claim 3
Dependent Claim
102 words
An apparatus according to claim 1, for the manufacture of a chlorate, in which the passage for conducting hypohalite downwardly past baffles to a lower portion of the cell and for holding it for a long enough period of time to convert a substantial proportion thereof to chlorate in operation, holds the hypochlorite long enough to convert at least 20% thereof to chlorate in one pass through the passage and includes at least one passageway for downward movement of electrolyte which is below the baffles and is substantially larger than the clearance passageways between the anodes and cathodes of the anode-cathode pairs.
Claim 4
Dependent Claim
77 words
An apparatus according to claim 2, for the production of sodium chlorate, wherein there is present a plurality of the passageways substantially larger than the clearance passageways between the anodes and the cathodes of the anode-cathode pairs, which larger passageways are separated from each other and are located between electrodes of the same electrical sign, and said larger passageways pass the electrolyte containing sodium chlorate downwardly to the cell bottom from a greater number of baffled passages.
Claim 5
Dependent Claim
126 words
An apparatus according to claim 3 wherein cross-sectional areas of such larger passageways for downward movement of the electrolyte from the baffled section of the apparatus to the cell bottom are each from 5 to 100 times that of each of the clearances between anodes and cathodes and the total of the cross-sectional areas of the larger passageways is sufficient and such passageways are so located that during operation of the apparatus electrochemical production of sodium chlorate proceeds with sufficient natural circulation of electrolyte due to lifting thereof through the clearance passageways between the electrode pairs by gas produced at the cathodes and downward movement of the electrolyte containing sodium hypochlorite and sodium chlorate past the baffles and to the cell bottom through the larger passageways.
Claim 6
Dependent Claim
44 words
An apparatus according to claim 4 wherein at least four cathodes are covered by said enclosure covering the tops of at least four clearance passageways between anode and cathode pairs and said cathodes are positioned asymmetrically with respect to the passageway above the enclosure.
Claim 7
Dependent Claim
93 words
An apparatus according to claim 2 wherein there are present from 5 to 50 enclosures, each covering the tops of at least four clearance passageways between anode and cathode pairs, and from 2 to 15 larger passageways below the baffles and substantially larger than the clearance passageways between the anodes and cathodes of the anode-cathode pairs, and the cross-sectional areas of the narrowed passageways communicating with the enclosures and through which gaseous products of electrolysis, including hydrogen, pass upwardly with electrolyte, are from 2 to 8% of the cross-sectional areas of the enclosures.
Claim 8
Dependent Claim
35 words
An apparatus according to claim 6 wherein anodes and cathodes are held apart from each other by a plurality of insulating synthetic organic polymeric plastic buttons through one of the electrodes and contacting the other.
Claim 9
Dependent Claim
46 words
An apparatus according to claim 1 wherein at least four cathodes are covered by said enclosure covering the tops of at least four clearance passageways between anode and cathode pairs and said enclosure is supported by the cathodes asymmetrically with respect to the passageway above it.
Claim 10
Dependent Claim
47 words
An apparatus according to claim 8 wherein the cathodes asymmetrically support a supporting means and the supporting means is within the enclosure, is held to enclosure walls and supports it and the narrowed passageway through which gaseous product of electrolysis, which includes hydrogen, passes upwardly with electrolyte.
Claim 11
Dependent Claim
43 words
A supporting member for an anode for a halate cell according to claim 1 wherein the anode is mounted on one side of the cell which comprises a longitudinal ledge having an insulating material on the top thereof on which the anode rests.
Claim 12
Dependent Claim
13 words
A supporting member according to claim 10 wherein the insulating material is polytetrafluoroethylene.
Claim 13
Dependent Claim
36 words
A supporting member according to claim 11 wherein the ledge is the top of a longitudinally and horizontally extending angle of steel or iron which is fastened to the interior steel wall of the halate cell.
Claim 14
Dependent Claim
35 words
A supporting member for a side entering anode of an electrolytic cell according to claim 1 which comprises a longitudinally extending horizontal ledge having an upper surface of insulating material on which the anode rests.
Claim 15
Dependent Claim
13 words
A supporting member according to claim 13 wherein the insulating material is polytetrafluoroethylene.
Claim 16
Dependent Claim
35 words
An apparatus according to claim 1 wherein anodes and cathodes are held apart from each other by a plurality of insulating synthetic organic polymeric plastic buttons through one of the electrodes and contacting the other.
Claim 17
Dependent Claim
47 words
Anodes for a chlorate cell according to claim 1 having a plurality of polytetrafluoroethylene buttons piercing surfaces thereof with heads of said buttons facing outwardly so as to contact a matching cathode to maintain a clearance passageway between the anode and cathode and prevent short circulating thereof.
Claim 18
Dependent Claim
117 words
In an apparatus for the manufacture of halate, which comprises an electrolytic cell including means for positioning a plurality of anodes and cathodes in spaced and paired relationships with one another, means for applying positive and negative electrical potentials to the anodes and cathodes, respectively, and means for circulating electrolyte through the cell, the improvement which comprises an enclosure covering the tops of at least four anode-cathode pairs and the clearance passageways between them and communicating with a passageway narrower than the enclosure and extending upwardly from it, through which electrolyte and gaseous product of electrolysis from the at least four electrode pairs may circulate upwardly due to the lifting action of the gaseous product of electrolysis.
Claim 19
Dependent Claim
117 words
In an apparatus for the manufacture of halate, which comprises an electrolytic cell including means for positioning a plurality of anodes and cathodes in spaced and paired relationships with one another, means for applying positive and negative electrical potentials to the anodes and cathodes, respectively, and means for circulating electrolyte through the cell, the improvement which comprises an enclosure covering the tops of at least four anode-cathode pairs and the clearance passageways between them and communicating with a passageway narrower than the enclosure and extending upwardly from it, through which electrolyte and gaseous product of electrolysis from the at least four electrode pairs may circulate upwardly due to the lifting action of the gaseous product of electrolysis.
Claim 20
Dependent Claim
60 words
An improvement according to claim 17 wherein two anode-cathode pairs are present per unit, said unit includes two cathodic surfaces on a base structure and two anode sheets, one facing each of the cathodic surfaces, and said units are substantially separate from each other but are in mutual contact with anode conductors and have top portions thereof within the enclosure.
Claim 21
Dependent Claim
32 words
An improvement according to claim 18 wherein anodes and cathodes are held apart from each other by polytetrafluoroethylene buttons passing through the anodes at pluralities of locations thereon and contacting the cathodes.
Claim 22
Dependent Claim
118 words
In an apparatus for the manufacture of halate, which comprises an electrolytic cell including a plurality of anodes and cathodes, means for positioning them in spaced and paired relationship with one another, means for applying positive and negative electrical potentials to the anodes and cathodes, respectively, and means for circulating electrolyte through the cell, the improvement which comprises said anodes and cathodes being in units containing two anode-cathode pairs, which units include two inner cathodic surfaces on a base structure and two outer anode sheets, one facing each of the cathode surfaces and being held apart from them, with such units being spaced apart by anode conductors which conduct positive electrical charges to the anodes of the units.
Claim 23
Dependent Claim
118 words
In an apparatus for the manufacture of halate, which comprises an electrolytic cell including a plurality of anodes and cathodes, means for positioning them in spaced and paired relationship with one another, means for applying positive and negative electrical potentials to the anodes and cathodes, respectively, and means for circulating electrolyte through the cell, the improvement which comprises said anodes and cathodes being in units containing two anode-cathode pairs, which units include two inner cathodic surfaces on a base structure and two outer anode sheets, one facing each of the cathode surfaces and being held apart from them, with such units being spaced apart by anode conductors which conduct positive electrical charges to the anodes of the units.
Claim 24
Independent Claim
187 words
A method for converting an apparatus for manufacture of halate, comprising an electrolytic cell including a plurality of monopolar dimensionally stable anodes and cathodes, means for positioning them in spaced and paired relationship within units comprising two anode-cathode pairs with two inner cathodic surfaces on a base structure and two outer anode surfaces, one facing each of the cathodic surfaces and separated from such surfaces, with enclosure means above each unit for trapping gas generated between the anodes and cathodes of the unit and transmitting it to a passageway through which it and electrolyte move upwardly and help to circulate electrolyte in the cell, to one capable of producing halate at the same rate and at a lower current density which comprises installing in said cell additional electrode units and replacing at least a portion of the enclosure means with an enlarged means for enclosing the tops of a plurality of such units, including an original and an added unit and having such enclosure for such plurality of units connect with an original single vertical passageway for circulation of generated gas and electrolyte upwardly through the cell.
Claim 25
Independent Claim
187 words
A method for converting an apparatus for manufacture of halate, comprising an electrolytic cell including a plurality of monopolar dimensionally stable anodes and cathodes, means for positioning them in spaced and paired relationship within units comprising two anode-cathode pairs with two inner cathodic surfaces on a base structure and two outer anode surfaces, one facing each of the cathodic surfaces and separated from such surfaces, with enclosure means above each unit for trapping gas generated between the anodes and cathodes of the unit and transmitting it to a passageway through which it and electrolyte move upwardly and help to circulate electrolyte in the cell, to one capable of producing halate at the same rate and at a lower current density which comprises installing in said cell additional electrode units and replacing at least a portion of the enclosure means with an enlarged means for enclosing the tops of a plurality of such units, including an original and an added unit and having such enclosure for such plurality of units connect with an original single vertical passageway for circulation of generated gas and electrolyte upwardly through the cell.
Claim 26
Dependent Claim
28 words
A method according to claim 21 wherein any spacers between electrode units are removed and installed units are spaced apart from other such units by mutual anode connectors.
Claim 27
Dependent Claim
40 words
A method according to claim 22 wherein spacers are removed between at least two units without installation of an enlarged enclosure and an additional unit so as to provide an enlarged passageway for circulation of electrolyte downwardly through the cell.
Claim 28
Independent Claim
239 words
A method of producing chlorate in a low current density chlorate cell which comprises electrolyzing aqueous sodium chloride solution to chlorine, hydrogen and sodium hydroxide and then converting such chlorine and such sodium hydroxide to sodium hypochlorite and then to sodium chlorate in the cell, which comprises passing a direct current through an aqueous electrolyte between anodes and cathodes 0.05 to 0.4 cm. apart at a current density of 0.28 to 0.4 ampere per square centimeter and a potential of 2.8 to 3.1 volts, while maintaining the concentration of sodium chloride in the aqueous electrolyte at from 100 to 150 grams per liter and the temperature thereof in the range of 50° to 85° C., removing products of electrolysis, including gas-entrained electrolyte, upwardly from the area of the electrodes and through a walled passageway to the top of a baffle return section of the electrolytic cell by means of a gravity flow differential force caused by gas entrainment with rising electrolyte, removing from the cell hydrogen gas containing less than 2% of chlorine and no more than 3% of oxygen, returning electrolyte to the bottom of the cell, by means of a baffled route, in which returning hypochlorite is converted to chlorate, withdrawing from the cell at the bottom thereof a portion of the electrolyte containing chlorate and adding substantially saturated aqueous sodium chloride solution or sodium chloride crystals to the cell to compensate for the materials removed therefrom.
Claim 29
Independent Claim
239 words
A method of producing chlorate in a low current density chlorate cell which comprises electrolyzing aqueous sodium chloride solution to chlorine, hydrogen and sodium hydroxide and then converting such chlorine and such sodium hydroxide to sodium hypochlorite and then to sodium chlorate in the cell, which comprises passing a direct current through an aqueous electrolyte between anodes and cathodes 0.05 to 0.4 cm. apart at a current density of 0.28 to 0.4 ampere per square centimeter and a potential of 2.8 to 3.1 volts, while maintaining the concentration of sodium chloride in the aqueous electrolyte at from 100 to 150 grams per liter and the temperature thereof in the range of 50° to 85° C., removing products of electrolysis, including gas-entrained electrolyte, upwardly from the area of the electrodes and through a walled passageway to the top of a baffle return section of the electrolytic cell by means of a gravity flow differential force caused by gas entrainment with rising electrolyte, removing from the cell hydrogen gas containing less than 2% of chlorine and no more than 3% of oxygen, returning electrolyte to the bottom of the cell, by means of a baffled route, in which returning hypochlorite is converted to chlorate, withdrawing from the cell at the bottom thereof a portion of the electrolyte containing chlorate and adding substantially saturated aqueous sodium chloride solution or sodium chloride crystals to the cell to compensate for the materials removed therefrom.
Claim 30
Dependent Claim
30 words
A method according to claim 24 wherein the current density is about 0.35 ampere per square centimeter, the voltage is about 3 volts and the temperature is about 80° C.
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) | 1983-08-19 | 1984-02-18 | 1984-08-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-08-19 | 1988-02-18 | 1988-08-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-08-19 | 1992-02-18 | 1992-08-19 | $7700.00 | Window Closed / Lapsed |