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US4368073A
Expired / Lapsed
US
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Use of the sodium salt of 2-mercaptopyridine-N-oxide to separate gold from acidic solutions
Assignee: Olin Corp
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Filing: 1981-04-30
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Granted: 1983-01-11
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Expires: 2001-04-30
Abstract
Abstract Disclosed is a process for separating gold from acidic solutions having a pH below about 3 which comprises the steps of: (a) adding a sufficient amount of the sodium salt of 2-mercaptopyridine-N-oxide to cause at least a portion of the gold in the aqueous acidic solution precipitate from the solution; and (b) separating the precipitated gold from the acidic solution. Also disclosed is that gold is selectively precipitated from acidic solutions containing other metals [e.g., Fe, Cu, Zn, Sn] when the molar ratio of added sodium 2-mercaptopyridine-N-oxide to gold in the acidic solution is less than about 1.5:1.
Inventors
- 👤 Sigmund Breister
- 👤 Joseph R. Reiner
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 09:46
CPC Classifications
C; C01; C01G; C01G7/00; C01G7/003; C22; C22B; C22B3/00; C22B3/20; C22B3/26; C22B3/34; Y; Y02; Y02P; Y02P10/00; Y02P10/20
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
95 words
A process for separating gold from acidic solutions having a pH below about 3 and containing at least one other metal selected from the group consisting of iron, copper, tin, lead or mixtures thereof, which comprises the steps of: (a) adding a sufficient amount of the sodium salt of 2-mercaptopyridine-N-oxide to said acidic solution to cause at least a portion of said gold in said acidic solution to precipitate from said acidic solution without any appreciable precipitation of said other metals; and (b) separating said precipitated gold from said acidic solution and said other metals.
Claim 2
Dependent Claim
95 words
A process for separating gold from acidic solutions having a pH below about 3 and containing at least one other metal selected from the group consisting of iron, copper, tin, lead or mixtures thereof, which comprises the steps of: (a) adding a sufficient amount of the sodium salt of 2-mercaptopyridine-N-oxide to said acidic solution to cause at least a portion of said gold in said acidic solution to precipitate from said acidic solution without any appreciable precipitation of said other metals; and (b) separating said precipitated gold from said acidic solution and said other metals.
Claim 3
Dependent Claim
17 words
The process of claim 1 wherein said separated precipitated gold is later recovered in its metallic form.
Claim 4
Dependent Claim
20 words
The process of claim 1 wherein at least a major portion of said gold in said acidic solution is precipitated.
Claim 5
Dependent Claim
34 words
The process of claim 1 wherein the amount of sodium salt of 2-mercaptopyridine-N-oxide added is in the range from about 0.5 to about 5.0 moles per one mole of said gold in said solution.
Claim 6
Dependent Claim
12 words
The process of claim 1 wherein said acidic solution is aqua regia.
Claim 7
Dependent Claim
103 words
A process for the selective precipitation and separation of gold from acidic solutions having a pH below about 3 and containing other metals selected from the group consisting of iron, copper, tin, lead, or mixtures thereof, which comprises the steps of: (a) adding sodium 2-mercaptopyridine-N-oxide to cause at least a portion of said gold in said acidic solution to precipitate from said acidic solution wherein the molar ratio of said added sodium 2-mercaptopyridine-N-oxide to said gold is less than about 1.5:1.0 without any appreciable precipitation of said other metals; and (b) separating said precipitated gold from said acidic solution and said other metals.
Claim 8
Dependent Claim
103 words
A process for the selective precipitation and separation of gold from acidic solutions having a pH below about 3 and containing other metals selected from the group consisting of iron, copper, tin, lead, or mixtures thereof, which comprises the steps of: (a) adding sodium 2-mercaptopyridine-N-oxide to cause at least a portion of said gold in said acidic solution to precipitate from said acidic solution wherein the molar ratio of said added sodium 2-mercaptopyridine-N-oxide to said gold is less than about 1.5:1.0 without any appreciable precipitation of said other metals; and (b) separating said precipitated gold from said acidic solution and said other metals.
Claim 9
Dependent Claim
24 words
The process of claim 6 wherein said molar ratio of said added sodium 2-mercaptopyridine-N-oxide to said gold is from about 0.5:1.0 to about 1.3:1.0.
Claim 10
Dependent Claim
17 words
The process of claim 7 wherein said separated precipitated gold is later recovered in its metallic form.
Claim 11
Dependent Claim
12 words
The process of claim 8 wherein said acidic solution is aqua regia.
Claim 12
Dependent Claim
20 words
The process of claim 7 wherein at least a major portion of said gold is precipitated from said acidic solution.
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) | 1986-01-10 | 1986-07-12 | 1987-01-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-01-10 | 1990-07-12 | 1991-01-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-01-10 | 1994-07-12 | 1995-01-11 | $7700.00 | Window Closed / Lapsed |