US3888747A
Expired / Lapsed
US
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Method of and apparatus for producing metal
Assignee: National Southwire Aluminum Co
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Filing: 1972-10-18
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Granted: 1975-06-10
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Expires: 1992-10-18
Abstract
Abstract A method involving the production of metal, in particular, aluminum by providing an electrolytic bath containing dissolved oxide of the metal to be produced in a reduction cell. A direct current flows through the bath and metal is collected on the bottom of the reduction cell. The method includes sensing the voltage drop across the cell and determining when this voltage exceeds a given level as an indication of anode effect. The method preferably involves extinguishing the anode effects which may occur. The apparatus for producing metal includes at least one reduction cell having electrodes for delivering direct current to an electrolytic bath containing dissolved oxide of the metal. An anode effect detector is operatively arranged to sense the voltage of the reduction cell and produces an output signal whenever this voltage exceeds a given level indicating the existence of an anode effect. The apparatus preferably includes devices responsive to the output from the anode effect detector for extinguishing the detected anode effects which may occur.
Inventors
- 👤 Joseph A Murphy
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 00:48
CPC Classifications
C; C25; C25C; C25C3/00; C25C3/06; C25C3/20
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
142 words
A METHOD OF PRODUCING METAL COMPRISING PROVIDING AN ELECTROLYTIC BATH CONTAINING DISSOLVED OXIDE OF THE METAL IN A REDUCTION CELL, CAUSING DIRECT CURRENT TO FLOW THROUGH SAID BATH, COLLECTING SAID METAL ON THE BOTTOM OF SAID REDUCTION CELL, SENSING THE DIRECT VOLTAGE ACROSS SAID CELL, PRODUCING A LIMITED OUTPUT SIGNAL CORRESPONDING TO THE VOLTAGE ACROSS SAID CELL UP TO A GIVEN LEVEL THEREOF, WHICH IS LESS THAN MAXIMYMUM ANODE EFFECT VOLTAGE LEVEL, AND PRODUCING A SIGNAL OF ONE LEVEL UPON OCCURRENCE OF ANY OUTPUT SIGNAL LEVEL IF THE LIMITED OUTPUT SIGNAL IS IN EXCESS OF A GIVEN THRESHOLD LEVEL, WHICH IS LESS THAN MAXIMUM POSSIBLE LEVEL OF THE LIMITED OUTPUT SIGNAL, AND DEVELOPING A SIGNAL OF ZERO LEVEL UPON OCCURRENCE OF ANY OUTPUT SIGNAL LEVEL BELOW THE GIVEN THRESHOLD LEVEL, THE SIGNAL OF ONE LEVEL BEING INDICATIVE OF OCCURRENCE OF ANODE EFFECT.
Claim 2
Independent Claim
142 words
A METHOD OF PRODUCING METAL COMPRISING PROVIDING AN ELECTROLYTIC BATH CONTAINING DISSOLVED OXIDE OF THE METAL IN A REDUCTION CELL, CAUSING DIRECT CURRENT TO FLOW THROUGH SAID BATH, COLLECTING SAID METAL ON THE BOTTOM OF SAID REDUCTION CELL, SENSING THE DIRECT VOLTAGE ACROSS SAID CELL, PRODUCING A LIMITED OUTPUT SIGNAL CORRESPONDING TO THE VOLTAGE ACROSS SAID CELL UP TO A GIVEN LEVEL THEREOF, WHICH IS LESS THAN MAXIMYMUM ANODE EFFECT VOLTAGE LEVEL, AND PRODUCING A SIGNAL OF ONE LEVEL UPON OCCURRENCE OF ANY OUTPUT SIGNAL LEVEL IF THE LIMITED OUTPUT SIGNAL IS IN EXCESS OF A GIVEN THRESHOLD LEVEL, WHICH IS LESS THAN MAXIMUM POSSIBLE LEVEL OF THE LIMITED OUTPUT SIGNAL, AND DEVELOPING A SIGNAL OF ZERO LEVEL UPON OCCURRENCE OF ANY OUTPUT SIGNAL LEVEL BELOW THE GIVEN THRESHOLD LEVEL, THE SIGNAL OF ONE LEVEL BEING INDICATIVE OF OCCURRENCE OF ANODE EFFECT.
Claim 3
Dependent Claim
13 words
A method as defined in claim 1 further comprising extinguishing the anode effect.
Claim 4
Dependent Claim
49 words
A method as defined in claim 1 wherein said step of providing an electrolytic bath includes routinely feeding the oxide of the metal into the bath at a rate insufficient to maintain the concentration of such material in said bath at levels which avoid the occurrence of anode effects.
Claim 5
Dependent Claim
49 words
A method as defined in claim 2 wherein said step of providing an electrolytic bath includes routinely feeding the oxide of the metal into the bath at a rate insufficient to maintain the concentration of such material in said bath at levels which avoid the occurrence of anode effects.
Claim 6
Dependent Claim
36 words
A method as defined in claim 1 wherein the step of providing an electrolytic bath comprises providing an electrolytic bath composed of alumina as the solute and cryolite as the solvent, the metal produced being aluminum.
Claim 7
Dependent Claim
31 words
A method as defined in claim 1 whereIn the step of sensing the direct voltage across said reduction cell is the step of intermittently sensing the voltage across said reduction cell.
Claim 8
Dependent Claim
42 words
A method as defined in claim 1 further comprising determining the resistance of said bath, and adjusting the anode-to-cathode electrode spacing of the electrode structure of said reduction cell to maintain the resistance of said bath within predetermined limits during regular electrolysis.
Claim 9
Dependent Claim
38 words
A method as defined in claim 2 wherein the step of extinguishing the anode effect comprises reducing the anode-to-cathode spacing of the electrode structure of said reduction cell and breaking crust present on the surface of said bath.
Claim 10
Dependent Claim
28 words
A method as defined in claim 8 further including, subsequent to the crust breaking, feeding additional metal oxide of the metal to be produced into said reduction cell.
Claim 11
Independent Claim
177 words
An apparatus for producing metal from an electrolytic bath containing dissolved oxide of the metal comprising at least one reduction cell having electrode means for delivering direct current to said electrolytic bath, said electrode means including anode electrode means and cathode electrode means; and anode effect detecting means including voltage limiting means responsive to voltage between said anode electrode means and said cathode electrode means for developing an output signal corresponding to the voltage between said anode electrode means and said cathode electrode means only up to a given level thereof below maximum anode effect voltage between these electrode means, and threshold level detector means responsive to the output signal from said limiting means for developing a signal of ONE level in response to signals exceeding a given threshold level which is less than maximum output signal level of said limiting means and for developing a signal of ZERO level in response to signals below the given threshold level from said limiting means, the signal of the ONE level being indicative of occurrence of an anode effect.
Claim 12
Independent Claim
177 words
An apparatus for producing metal from an electrolytic bath containing dissolved oxide of the metal comprising at least one reduction cell having electrode means for delivering direct current to said electrolytic bath, said electrode means including anode electrode means and cathode electrode means; and anode effect detecting means including voltage limiting means responsive to voltage between said anode electrode means and said cathode electrode means for developing an output signal corresponding to the voltage between said anode electrode means and said cathode electrode means only up to a given level thereof below maximum anode effect voltage between these electrode means, and threshold level detector means responsive to the output signal from said limiting means for developing a signal of ONE level in response to signals exceeding a given threshold level which is less than maximum output signal level of said limiting means and for developing a signal of ZERO level in response to signals below the given threshold level from said limiting means, the signal of the ONE level being indicative of occurrence of an anode effect.
Claim 13
Dependent Claim
32 words
An apparatus as defined in claim 10 wherein said threshold level detecting means is a diode which becomes conductive at approximately 7.5 volts, said diode being substantially nonconductive at lower voltage levels.
Claim 14
Dependent Claim
32 words
An apparatus as defined in claim 11 wherein said limiting means is a limiting amplifier, said amplifier being operatively arranged to limit at approximately 10.0 volts and having a gain of one.
Claim 15
Dependent Claim
26 words
An apparatus as defined in claim 10 further comprising means responsive to the output of said threshold level detecting means for extinguishing the detected anode effects.
Claim 16
Dependent Claim
43 words
An apparatus as defined in claim 13 wherein said means for extinguishing the detected anode effects includes means for reducing the spacing between said anode electrode means and said cathode electrode means and means for breaking crust on the surface of said bath.
Claim 17
Dependent Claim
32 words
An apparatus as defined in claim 14 wherein said means for extinguishing the detected anode effects includes means for feeding additional oxide of the metal to be produced into said reduction cell.
Claim 18
Dependent Claim
20 words
An apparatus as defined in claim 15 further comprising means for routinely feeding oxide of the metal into said bath.
Claim 19
Dependent Claim
36 words
An apparatus as defined in claim 16 wherein said means for routinely feeding oxide of the metal into said bath is operatively arranged to feed such material at a rate insufficient to avoid all anode effects.
Claim 20
Dependent Claim
51 words
An apparatus as defined in claim 10 further comprising means for determining the resistance of said bath and means responsive to output from said means for determining resistance for adjusting spacing between said anode electrode means and said cathode electrode means to maintain the resistance of said bath within predetermined limits.
Claim 21
Dependent Claim
41 words
An apparatus as defined in claim 13 wherein said means for extinguishing the detected anode effects includes means for reducing spacing between said anode electrode means and said cathode electrode means in response to signals fRom said threshold level detecting means.
Claim 22
Dependent Claim
43 words
An apparatus as defined in claim 19 wherein said means for extinguishing the detected anode effects further includes means for feeding additional oxide of the metal to be produced into said reduction cell in response to signals from said anode effect detecting means.
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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) | 1978-06-09 | 1978-12-09 | 1979-06-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-06-09 | 1982-12-09 | 1983-06-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-06-09 | 1986-12-09 | 1987-06-10 | $7700.00 | Window Closed / Lapsed |