US4404071A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of treating electrolytic solution of copper for purification and reuse thereof
Assignee: Dowa Holdings Co Ltd
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Filing: 1982-04-26
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Granted: 1983-09-13
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Expires: 2002-04-26
Abstract
Abstract There is disclosed an improved method of treating a spent electrolyte of copper from a cell for electrolytic refining of copper for the purpose of purification and reuse of the spent electrolyte. The process comprises the steps of: pretreating the spent electrolyte for removing copper therefrom until the copper content is greatly reduced but still remains at a level which is substantially higher than the total content of various metal ion impurities, preferably to a concentration of 10-13 g/l of Cu; blowing a hydrogen sulfide gas into the pretreated solution at a temperature of 40° C. or higher until the redox potential of solution becomes a certain predetermined value to precipitate metal ions; filtering the treated solution to separate the residue available as a raw material for copper smelting from a filtrate which consists essentially of sulfuric acid; and returning the filtrate to the cell for electrolytic refining of copper.
Inventors
- 👤 Hideki Abe
- 👤 Kiyomi Yamaguchi
- 👤 Yuzo Asano
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 04:16
CPC Classifications
C; C22; C22B; C22B15/00; C22B15/0063; C22B15/0084; C22B15/0089; C22B15/0093; C25; C25C; C25C1/00; C25C1/12; C25C7/00; C25C7/06; Y; Y02; Y02P; Y02P10/00; Y02P10/20
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
159 words
A method of treating a spent electrolytic solution containing a major amount of copper and a minor amount of various metal ion impurities containing at least arsenic, which method comprises the steps of: removing copper from said electrolytic solution in a pretreatment operation until the copper content is greatly reduced but still remains at a level which is substantially larger than the total of said impurities; passing hydrogen sulfide gas into said pretreated solution at an elevated temperature of 40° C. or higher until the redox potential is at least equal to a certain predetermined value to precipitate substantially all the copper together with said metal ion impurities present in the solution; filtering the thus treated solution to separate the precipitates as a residue which can be used as part of the raw material in the process of copper smelting from a filtrate consisting essentially of sulfuric acid; and returning the filtrate to a copper electrolytic cell for reuse.
Claim 2
Independent Claim
159 words
A method of treating a spent electrolytic solution containing a major amount of copper and a minor amount of various metal ion impurities containing at least arsenic, which method comprises the steps of: removing copper from said electrolytic solution in a pretreatment operation until the copper content is greatly reduced but still remains at a level which is substantially larger than the total of said impurities; passing hydrogen sulfide gas into said pretreated solution at an elevated temperature of 40° C. or higher until the redox potential is at least equal to a certain predetermined value to precipitate substantially all the copper together with said metal ion impurities present in the solution; filtering the thus treated solution to separate the precipitates as a residue which can be used as part of the raw material in the process of copper smelting from a filtrate consisting essentially of sulfuric acid; and returning the filtrate to a copper electrolytic cell for reuse.
Claim 3
Dependent Claim
19 words
The method as defined in claim 1 wherein said pretreated spent electrolyte contains 5 to 20 g/l of copper.
Claim 4
Dependent Claim
19 words
The method as defined in claim 1 wherein said pretreated spent electrolyte contains 8 to 15 g/l of copper.
Claim 5
Dependent Claim
19 words
The method as defined in claim 1 wherein said pretreated spent electrolyte contains 10 to 13 g/l of copper.
Claim 6
Independent Claim
26 words
The method as defined in any of claims 1 to 4 wherein said electrolyte is one taken out of a cell for electrolytic refining of copper.
Claim 7
Independent Claim
22 words
The method as defined in any of claims 1 or 4 wherein said pretreatment is carried out by electrolytic extraction of copper.
Claim 8
Independent Claim
24 words
The method as defined in any of claims 1 to 4 wherein said temperature is in the range of 40° C. to 90° C.
Claim 9
Independent Claim
24 words
The method as defined in any of claims 1 to 4 wherein said temperature is in the range of 50° C. to 70° C.
Claim 10
Independent Claim
18 words
The method as defined in any of claims 1 to 4 wherein said temperature is about 60° C.
Claim 11
Independent Claim
25 words
The method as defined in any of claims 1 to 4 wherein said redox potential is in the range of 200 mV to 300 mV.
Claim 12
Independent Claim
25 words
The method as defined in any of claims 1 to 4 wherein said electrolytic potential is in the range of 230 mV to 280 mV.
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) | 1986-09-12 | 1987-03-14 | 1987-09-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-09-12 | 1991-03-14 | 1991-09-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-09-12 | 1995-03-14 | 1995-09-13 | $7700.00 | Window Closed / Lapsed |