Patent US4030990A successfully refreshed from Google Patents.
US4030990A
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Process for recovering electrolytic copper of high purity by means of reduction electrolysis
Assignee: Duisburger Kupferhuette
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Filing: 1976-06-22
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Granted: 1977-06-21
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Expires: 1996-06-22
Abstract
Abstract Copper sulfate solution obtained by the sulfuric acid leaching of cupriferous material and containing impurities such as Fe, As, Sb, Bi, Se, Te, Sn, Pb, Cl, Ag, Hg, and PO 4 , are subjected to a two step purification process. In the first step, the pH is adjusted to 2.7-3.3 with, e.g. Ca(OH) 2 , and the potential in relation to the standard hydrogen electrode is adjusted to at least 575 mv with an oxidizing agent, e.g. air. The temperature is 50°-90° C. Impurities precipitate and are separated. Se, Cl, and possibly Ag and Hg remain in solution and are removed in the second step, wherein the potential is reduced to below 350 mv by addition of a cupriferous reducing agent, e.g. Cu or Cu 2 O. The pH is below 3 and the temperature is below 50° C. Impurities precipitate as copper (I) compounds, and are separated to provide the solution in condition for the electrolysis. The copper produced is of high purity, having a conductivity of at least 58.8 mho × m/mm 2 and a maximum semi-hard temperature of 200° C.
Inventors
- 👤 Norbert L. Piret
- 👤 Hans Joachim Rabben
- 👤 Herbert Kudelka
- 👤 Siegbert Schmidt
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 15:29
CPC Classifications
C; C25; C25C; C25C1/00; C25C1/12; C22; C22B; C22B15/00; C22B15/0063; C22B15/0065; C22B15/0067; C22B15/0071; C22B15/0084; C22B15/0089; C22B15/0091; C22B15/0093; Y; Y02; Y02P; Y02P10/00; Y02P10/20
Claims Analysis
Total Claims: 34
Claim 1
Independent Claim
187 words
Process for producing high purity electrolytic copper with an electric conductivity of at least 58.8 mho × m/mm 2 , and a maximum semi-hard temperature of 200° C by reduction electrolysis of a copper sulphate solution obtained by sulphuric acid leaching of crude cupriferous materials and containing in solution impurities which interfere with the electrolysis, characterized in that prior to the electrolysis the copper sulphate solution is subjected to purification to at least partially remove said impurities, comprising: a first step in which the copper sulfate solution is maintained at a pH of 2.7-3.3, and a potential of at least 575 mv in relation to the standard hydrogen electrode for precipitation of part of said impurities, and the precipitated impurities are removed from the solution, and a second step in which the potential of the solution is reduced for formation of copper (I) compounds of at least part of the remaining impurities and precipitation of said copper (I) compounds, and the precipitated copper (I) compounds are removed from the solution, and electrolyzing solution subjected to said first and second steps to produce said high purity electrolytic copper.
Claim 2
Dependent Claim
187 words
Process for producing high purity electrolytic copper with an electric conductivity of at least 58.8 mho × m/mm 2 , and a maximum semi-hard temperature of 200° C by reduction electrolysis of a copper sulphate solution obtained by sulphuric acid leaching of crude cupriferous materials and containing in solution impurities which interfere with the electrolysis, characterized in that prior to the electrolysis the copper sulphate solution is subjected to purification to at least partially remove said impurities, comprising: a first step in which the copper sulfate solution is maintained at a pH of 2.7-3.3, and a potential of at least 575 mv in relation to the standard hydrogen electrode for precipitation of part of said impurities, and the precipitated impurities are removed from the solution, and a second step in which the potential of the solution is reduced for formation of copper (I) compounds of at least part of the remaining impurities and precipitation of said copper (I) compounds, and the precipitated copper (I) compounds are removed from the solution, and electrolyzing solution subjected to said first and second steps to produce said high purity electrolytic copper.
Claim 3
Dependent Claim
35 words
Process of claim 1, wherein said copper sulfate solution contains sulfuric acid and the pH thereof is above 2.7, and sulfuric acid consuming material is added to the solution to provide said pH of 2.7-3.3.
Claim 4
Dependent Claim
34 words
Process of claim 2, wherein the sulphuric acid consuming material is at least one of hydroxides, carbonates or basic sulphates of metals the cations of which form compounds of low solubility with sulphate ions.
Claim 5
Dependent Claim
21 words
Process of claim 3, wherein the sulfuric acid consuming material is at least one of Ca(OH) 2 and CaCO 3 .
Claim 6
Dependent Claim
65 words
Process of claim 4, wherein the first step the potential of at least 575 mv is provided by addition of an oxidizing agent to the solution, the temperature is 50°-90° C, and in the second step the potential of the solution is reduced to below 350 mv by adding a cupriferous reducing agent, the temperature is below 50° C, and the pH is below 3.
Claim 7
Dependent Claim
136 words
Process of claim 4, wherein said impurities in the copper sulfate solution subject to said first step are of the group Fe, As, Sb, Bi, Se, Te, Sn, Pb, Cl, Ag, Hg, and PO 4 , and said remaining impurities are of the group Se, Cl, Ag, and Hg, and in the first step the potential of at least 575 mv is provided by addition of an oxidizing agent to the solution, the temperature is 50°-90° C, and in the second step the potential of the solution is reduced to below 350 mv by adding a cupriferous reducing agent, the temperature is below 50° C, and the pH is below 3, and the solution subjected to the first and second step contains 2-5 g/l of free sulfuric acid, a solids concentration of less than 20 mg/l.
Claim 8
Dependent Claim
24 words
Process of claim 2, wherein the sulfuric acid consuming material is at least one of metallic copper and copper compounds which consume sulfuric acid.
Claim 9
Dependent Claim
26 words
Process of claim 2, wherein the sulfuric acid consuming material is at least one of metallic copper, Cu 2 O, Cu(OH) 2 and basic copper sulfate.
Claim 10
Dependent Claim
27 words
Process of claim 1, wherein in the first step the potential of at least 575 mv is provided by addition of an oxidizing agent to the solution.
Claim 11
Dependent Claim
22 words
Process of claim 9, wherein in the first step the oxidizing agent is air, oxygen, or an oxygen-containing gas other than air.
Claim 12
Dependent Claim
14 words
Process of claim 9, wherein the oxidizing agent is H 2 O 2 .
Claim 13
Dependent Claim
12 words
Process of claim 9, wherein the oxidizing agent is MnO 2 .
Claim 14
Dependent Claim
21 words
Process of claim 1, the potential of the solution in the second step is reduced by adding a cupriferous reducing agent.
Claim 15
Dependent Claim
12 words
Process of claim 13, wherein the cupriferous reduction agent is metallic copper.
Claim 16
Dependent Claim
13 words
Process of claim 13, wherein the cupriferous reducing agent is Cu 2 O.
Claim 17
Dependent Claim
17 words
Process of claim 13, wherein the cupriferous reducing agent is a sulfuric acid suspension of cuprous oxide.
Claim 18
Dependent Claim
39 words
Process of claim 1, wherein in the second step the precipitated copper (I) compounds are removed from the solution by precoat fine filtration to the extent that the filtered solution has a solids content of less than 20 mg/l.
Claim 19
Dependent Claim
13 words
Process of claim 17, wherein said solids content is less than 10 mg/l.
Claim 20
Dependent Claim
49 words
Process of claim 1, wherein said impurities in the copper sulfate solution subject to said first step are of the group Fe, As, Sb, Bi, Se, Te, Sn, Pb, Cl, Ag, Hg, and PO 4 , and said remaining impurities are of the group Se, Cl, Ag, and Hg.
Claim 21
Dependent Claim
29 words
Process of claim 19, wherein the solution subjected to the first and second step contains 2-5 g/l of free sulfuric acid, a solids concentration of less than 20 mg/l.
Claim 22
Dependent Claim
73 words
Process of claim 1, wherein the impurities comprise at least one of As and PO 4 , and in the first step the As is precipitated as FeAsO 4 and the PO 4 is precipitated as FePO 4 , and the copper sulfate solution treated in the first step contains Fe in amount of at least about 120% of the stoichiometric amount for the formation of said FeAsO 4 and FePO 4 .
Claim 23
Dependent Claim
39 words
Process of claim 21, wherein the impurities comprise chloride ion and said chloride ion is precipitated in the second step, and the temperature in the second step is below 50° C, and above the crystallization temperature of the solution.
Claim 24
Dependent Claim
14 words
Process of claim 1, wherein the temperature in the first step is 50°-90° C.
Claim 25
Dependent Claim
14 words
Process of claim 1, wherein the temperature in the first step is 60°-80° C.
Claim 26
Dependent Claim
25 words
Process of claim 1, wherein the potential in the second step is reduced to below 350 mv in relation to the standard H 2 electrode.
Claim 27
Dependent Claim
24 words
Process of claim 1, wherein the potential in the second step is reduced to 340-300 mv in relation to the standard H 2 electrode.
Claim 28
Dependent Claim
39 words
Process of claim 1, wherein the impurities comprise chloride ion and said chloride ion is precipitated in the second step, and the temperature in the second step is below 50° C, and above the crystallization temperature of the solution.
Claim 29
Dependent Claim
39 words
Process of claim 1, wherein the impurities comprise chloride ion and said chloride ion is precipitated in the second step, and the temperature in the second step is below 50° C, and above the crystallization temperature of the solution.
Claim 30
Dependent Claim
18 words
Process of claim 1, wherein the potential in the second step is reduced by adding SO 2 .
Claim 31
Dependent Claim
14 words
Process of claim 1, wherein the pH for the second step is below 3.
Claim 32
Dependent Claim
14 words
Process of claim 1, wherein the pH for the second step is below 1.5-2.5.
Claim 33
Dependent Claim
66 words
Process of claim 1, wherein said copper sulfate solution is produced by leaching said crude cupriferous material with sulfuric acid, and said leaching results in said copper sulfate solution admixed with undissolved solid particles of the crude cupriferous material, said admixture is subjected to the first step, and said undissolved solid particles are removed simultaneously with the removal of said precipitated impurities in the first step.
Claim 34
Dependent Claim
18 words
Process of claim 1, wherein the pH of the first step is 2.9-3.1, the potential is 590-670 mv.
References Cited (Backward Citations)
US1598296A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-06-20 | 1980-12-20 | 1981-06-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-06-20 | 1984-12-20 | 1985-06-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-06-20 | 1988-12-20 | 1989-06-21 | $7700.00 | Window Closed / Lapsed |