US4021319A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electrolytic process for recovery of silver from photographic fixer solution
Assignee: NOHREN FRANCES W 5170 126TH AVENUE NORTH CLEARWATER FL 33520
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Filing: 1975-09-24
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Granted: 1977-05-03
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Expires: 1995-09-24
Abstract
Abstract A method of electrolytically removing silver from a photographic fixer solution comprising the steps of placing the photographic fixer solution in a cell having an anode chamber and a cathode chamber, with said chamber being separated by a diaphragm having a pore size of between about 1.0 microns to 500 microns and applying a direct current across the anode and cathode to create a current density of between about 0.001 and 5 amperes per square inch at the cathode to thereby cause argentic oxide to precipitate at the cathode and an equivalent amount of elemental sulfur to precipitate at the anode. The cell is preferably maintained at a temperature of between about 20 DEG C. and 60 DEG C. The cell can be operated as a flow cell by maintaining a hydraulic head between the chambers to determine the flow across the diaphragm. When the cell is operated as a flow cell, a minimum specific amount of photographic fixer must be conveyed to the cell to prevent oxidation of sulfur and escape of SO2 gas.
Inventors
- 👤 Karl Moeglich
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 08:43
CPC Classifications
C; C25; C25B; C25B1/00; C25B1/01
Claims Analysis
Total Claims: 43
Claim 1
Independent Claim
96 words
A method of electrolytically removing silver from a photographic fixer solution comprising the steps of placing said photographic fixer solution in a cell having an anode chamber containing an anode and a cathode chamber containing a cathode with said chambers being created by a diaphragm having a pore size of a proper magnitude which will aid in creating a caustic condition in the cathode compartment, and applying a direct current across said anode and cathode to create a current density of a sufficient magnitude at said cathode to cause argentic oxide to precipitate at said cathode.
Claim 2
Independent Claim
96 words
A method of electrolytically removing silver from a photographic fixer solution comprising the steps of placing said photographic fixer solution in a cell having an anode chamber containing an anode and a cathode chamber containing a cathode with said chambers being created by a diaphragm having a pore size of a proper magnitude which will aid in creating a caustic condition in the cathode compartment, and applying a direct current across said anode and cathode to create a current density of a sufficient magnitude at said cathode to cause argentic oxide to precipitate at said cathode.
Claim 3
Dependent Claim
18 words
A method as set forth in claim 1 wherein said pore size is between about 20μ and 300μ.
Claim 4
Dependent Claim
25 words
A method as set forth in claim 2 wherein said current density at said cathode is between about 0.1 and 1 ampere per square inch.
Claim 5
Dependent Claim
25 words
A method as set forth in claim 2 wherein said current density at said cathode is between about 0.3 and 0.8 ampere per square inch.
Claim 6
Dependent Claim
25 words
A method as set forth in claim 2 wherein said current density at said cathode is between about 0.001 and 5 amperes per square inch.
Claim 7
Dependent Claim
61 words
A method as set forth in claim 1 including the step of maintaining a positive hydraulic pressure between said anode chamber and said cathode chamber so as to create a flow through said cell, and flowing the photographic solution into the compartment of said cell having the higher hydraulic pressure and withdrawing the liquid from the other compartment of said cell.
Claim 8
Dependent Claim
25 words
A method as set forth in claim 6 wherein said current density at said cathode is between about 0.001 and 5 amperes per square inch.
Claim 9
Dependent Claim
18 words
A method as set forth in claim 7 wherein said pore size is between about 20μ and 300μ.
Claim 10
Dependent Claim
18 words
A method as set forth in claim 7 wherein said pore size is between about 50μ and 120μ.
Claim 11
Dependent Claim
18 words
A method as set forth in claim 6 wherein said pore size is between about 50μ and 120μ.
Claim 12
Dependent Claim
25 words
A method as set forth in claim 10 wherein said current density at said cathode is between about 0.1 and 1 ampere per square inch.
Claim 13
Dependent Claim
25 words
A method as set forth in claim 10 wherein said current density at said cathode is between about 0.3 and 0.8 ampere per square inch.
Claim 14
Dependent Claim
25 words
A method as set forth in claim 1 wherein said current density at said cathode is between about 0.001 and 5 amperes per square inch.
Claim 15
Dependent Claim
18 words
A method as set forth in claim 13 wherein said pore size is between about 20μ and 300μ.
Claim 16
Dependent Claim
18 words
A method as set forth in claim 13 wherein said pore size is between about 50μ and 120μ.
Claim 17
Dependent Claim
25 words
A method as set forth in claim 1 wherein said current density at said cathode is between about 0.3 and 0.8 ampere per square inch.
Claim 18
Dependent Claim
18 words
A method as set forth in claim 16 wherein said pore size is between about 50μ and 120μ.
Claim 19
Dependent Claim
26 words
A method as set forth in claim 16 including the step of maintaining the temperature of said cell at between about 20° C. and 60° C.
Claim 20
Dependent Claim
26 words
A method as set forth in claim 16 including the step of maintaining the temperature of said cell at between about 20° C. and 45° C.
Claim 21
Dependent Claim
31 words
A method as set forth in claim 1 including the step of providing an additional electrode in said cathode chamber, and applying alternating current across said cathode and said additional electrode.
Claim 22
Dependent Claim
18 words
A method as set forth in claim 20 wherein said pore size is between about 50μ and 120μ.
Claim 23
Dependent Claim
26 words
A method as set forth in claim 21 wherein the direct current density at said cathode is between about 0.1 and 1 ampere per square inch.
Claim 24
Dependent Claim
33 words
A method as set forth in claim 1 wherein a minimum specific amount of said photographic fixer is conveyed to said cell to prevent oxidation of sulfur and escape of SO 2 gas.
Claim 25
Dependent Claim
35 words
A method as set forth in claim 23 wherein said pore size is between about 20μ and 300μ and said current density at said cathode is between about 0.001 and 5 amperes per square inch.
Claim 26
Dependent Claim
25 words
A method as set forth in claim 24 wherein said current density at said cathode is between about 0.1 and 1 ampere per square inch.
Claim 27
Dependent Claim
18 words
A method as set forth in claim 1 wherein said pore size is between about 1μ and 500μ.
Claim 28
Dependent Claim
18 words
A method as set forth in claim 1 wherein said pore size is between about 50μ and 120μ.
Claim 29
Dependent Claim
25 words
A method as set forth in claim 1 wherein said current density at said cathode is between about 0.1 and 1 ampere per square inch.
Claim 30
Dependent Claim
132 words
A continuous method for electrolytically processing a photographic fixer solution to remove silver therefrom comprising the steps of: providing a cell having an anode chamber containing an anode and a cathode chamber containing a cathode with said chambers being created by a diaphragm having a pore size of a predetermined magnitude disposed therebetween, said chambers adapted to contain photographic fixer solution; continuously supplying photographic fixer solution to said cell; maintaining a positive hydraulic pressure across said diaphragm to ensure a flow therethrough; maintaining a caustic condition in the cathode chamber and applying a direct current across said anode and cathode to create a current density of a sufficient magnitude at said cathode to cause argentic oxide to precipitate at said cathode for collection; and continuously withdrawing said processed solution from said cell.
Claim 31
Dependent Claim
132 words
A continuous method for electrolytically processing a photographic fixer solution to remove silver therefrom comprising the steps of: providing a cell having an anode chamber containing an anode and a cathode chamber containing a cathode with said chambers being created by a diaphragm having a pore size of a predetermined magnitude disposed therebetween, said chambers adapted to contain photographic fixer solution; continuously supplying photographic fixer solution to said cell; maintaining a positive hydraulic pressure across said diaphragm to ensure a flow therethrough; maintaining a caustic condition in the cathode chamber and applying a direct current across said anode and cathode to create a current density of a sufficient magnitude at said cathode to cause argentic oxide to precipitate at said cathode for collection; and continuously withdrawing said processed solution from said cell.
Claim 32
Dependent Claim
53 words
The method of claim 29 wherein said diaphragm comprises a pair of mutually spaced diaphragm members, said method further comprising maintaining fixer solution at a first predetermined level in said chambers; and maintaining fixer solution at a second predetermined level between said members whereby a constant hydraulic pressure is maintained across said diaphragm.
Claim 33
Dependent Claim
22 words
The method of claim 30 wherein said current density at said cathode is between about 0.001 and 5 amperes per square inch.
Claim 34
Dependent Claim
23 words
The method of claim 31 wherein said direct current density at said cathode is between about 0.1 and 1 amperes per square inch.
Claim 35
Dependent Claim
17 words
The method of claim 31 wherein said pore size is between about 20 mu and 300 mu.
Claim 36
Dependent Claim
17 words
The method of claim 31 wherein said pore size is between about 50 mu and 120 mu.
Claim 37
Dependent Claim
28 words
The method of claim 30 including the step of providing an additional electrode in said cathode chamber, and applying alternating current across said cathode and said additional electrode.
Claim 38
Dependent Claim
40 words
The method of claim 29 further comprising maintaining said fixer solution at a first predetermined level in said cathode chamber and at a second predetermined level in said anode chamber whereby a constant hydraulic pressure is maintained across said diaphragm.
Claim 39
Dependent Claim
22 words
The method of claim 36 wherein said current density at said cathode is between about 0.001 and 5 amperes per square inch.
Claim 40
Dependent Claim
23 words
The method of claim 37 wherein the direct current density at said cathode is between about 0.1 and 1 ampere per square inch.
Claim 41
Dependent Claim
17 words
The method of claim 37 wherein said pore size is between about 20 mu and 300. mu.
Claim 42
Dependent Claim
17 words
The method of claim 37, wherein said pore size is between about 50 mu and 120 mu.
Claim 43
Dependent Claim
27 words
The method of claim 36 including the step of providing an additional electrode in said cathode chamber, and applying alternating current across said cathode and said electrode.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1980-05-02 | 1980-11-01 | 1981-05-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-05-02 | 1984-11-01 | 1985-05-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-05-02 | 1988-11-01 | 1989-05-03 | $7700.00 | Window Closed / Lapsed |