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Patent US4092154A successfully refreshed from Google Patents.
US4092154A
Expired / Lapsed
US
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Aluminum containing precipitating agent for precious metals and method for its use
Assignee: TECHNIC Inc A RHODE ISLAND CORP
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Filing: 1976-09-02
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Granted: 1978-05-30
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Expires: 1996-09-02
Abstract
Abstract A precipitating agent for precipitating precious metals such as gold from aqueous cyanide solution of the precious metal ions includes aluminum powder and a reducing agent such as sodium hydrosulfite, sodium borohydride or hydrazine. The precipitating agent may also include an alkali metal carbonate, such as potassium carbonate, as an activator. The precipitating agent efficiently reduces the precious metal ions to elemental metal for recovery and also consumes a portion of the cyanide content, which is often high in such solutions. The method of use includes adjusting the precious metals cyanide solution to a high pH, adding the precipitating agent with agitation, preferably in incremental portions of the amount required. The solution is allowed to stand to permit the precipitated metal to settle, and the metal is separated from the solution.
Inventors
- 👤 George Dietz, Jr.
- 👤 Robert M. Skomoroski
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 16:20
CPC Classifications
C; C22; C22B; C22B11/00; C22B11/08; C22B5/00; C22B5/02; C22B5/04
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
53 words
A precipitating agent for recovering precious metal values from aqueous alkaline solutions containing ions of the precious metals and reducing the cyanide content, if any, of such solutions, comprising: an admixture of aluminum powder and a reducing agent selected from the class consisting of alkali metal hydrosulfite, alkali metal borohydride and hydrazine compounds.
Claim 2
Dependent Claim
53 words
A precipitating agent for recovering precious metal values from aqueous alkaline solutions containing ions of the precious metals and reducing the cyanide content, if any, of such solutions, comprising: an admixture of aluminum powder and a reducing agent selected from the class consisting of alkali metal hydrosulfite, alkali metal borohydride and hydrazine compounds.
Claim 3
Dependent Claim
21 words
The precipitating agent of claim 1 containing about 3 parts by weight reducing agent to 1 part by weight aluminum powder.
Claim 4
Dependent Claim
15 words
The precipitating agent of claim 1 further including as an activator an alkali metal carbonate.
Claim 5
Dependent Claim
31 words
The precipitating agent of claim 3 comprising about 40 to 70% by weight reducing agent, about 10 to 35% by weight aluminum powder and about 10 to 35% by weight activator.
Claim 6
Dependent Claim
31 words
The precipitating agent of claim 4 wherein said reducing agent is selected from the class consisting of sodium hydrosulfite, sodium borohydride and hydrazine, and said alkali metal carbonate is potassium carbonate.
Claim 7
Dependent Claim
21 words
The precipitating agent of claim 4 wherein said reducing agent is sodium hydrosulfite and said alkali metal carbonate is potassium carbonate.
Claim 8
Dependent Claim
30 words
The precipitating agent of claim 6 comprising about 50 to 70% by weight sodium hydrosulfite, 15 to 40% by weight aluminum powder and 10 to 15% by weight potassium carbonate.
Claim 9
Dependent Claim
37 words
The precipitating agent of claim 7 wherein said sodium hydrosulfite, aluminum powder and potassium carbonate are present in the following approximate proportions: ______________________________________
Parts by Weight
______________________________________
sodium hydrosulfite 6.66
aluminum powder 2.22
potassium carbonate 1.11
______________________________________
Claim 10
Dependent Claim
13 words
The precipitating agent of claim 5 wherein said reducing agent is sodium borohydride.
Claim 11
Dependent Claim
30 words
The precipitating agent of claim 9 comprising about 60 to 70% by weight sodium borohydride, 10 to 30% by weight aluminum powder, and 10 to 20% by weight potassium carbonate.
Claim 12
Dependent Claim
14 words
The precipitating agent of claim 5 wherein said reducing agent is a hydrazine compound.
Claim 13
Dependent Claim
29 words
The precipitating agent of claim 11 comprising about 40 to 50% by weight hydrazine, 15 to 35% by weight aluminum powder, and 25 to 35% by weight potassium carbonate.
Claim 14
Dependent Claim
30 words
The precipitating agent of claim 1 wherein the aluminum powder is of a particle size such that at least 90% of the aluminum particles pass through a 200 mesh screen.
Claim 15
Dependent Claim
30 words
The precipitating agent of claim 13 wherein the aluminum powder is of a particle size such that at least 90% of the aluminum particles pass through a 325 mesh screen.
Claim 16
Independent Claim
97 words
A method for the precipitation of precious metal ions from aqueous alkaline solution of said ions and for reducing the cyanide content, if any, of the solution comprising the steps of: a. heating an aqueous alkaline solution of precious metal ions to a temperature of at least about 37.7° C; b. adding to said solution a precipitating agent comprising an admixture of aluminum powder and a reducing agent selected from the class consisting of alkali metal hydrosulfite, alkali metal borohydride and hydrazine compounds to precipitate elemental precious metal; and c. separating precipitated precious metal from the solution.
Claim 17
Independent Claim
97 words
A method for the precipitation of precious metal ions from aqueous alkaline solution of said ions and for reducing the cyanide content, if any, of the solution comprising the steps of: a. heating an aqueous alkaline solution of precious metal ions to a temperature of at least about 37.7° C; b. adding to said solution a precipitating agent comprising an admixture of aluminum powder and a reducing agent selected from the class consisting of alkali metal hydrosulfite, alkali metal borohydride and hydrazine compounds to precipitate elemental precious metal; and c. separating precipitated precious metal from the solution.
Claim 18
Dependent Claim
17 words
The method of claim 15 wherein the precipitating agent further includes as an activator an alkali carbonate.
Claim 19
Dependent Claim
26 words
The method of claim 16 further including the preliminary step of testing the pH of the solution, and maintaining the pH at about 12 or higher.
Claim 20
Dependent Claim
34 words
The method of claim 16 wherein said precipitating agent is added in increments and agitation of said solution to disperse said precipitating agent therein is carried out between the incremental additions of precipitating agent.
Claim 21
Dependent Claim
46 words
The method of claim 15 wherein said reducing agent is sodium hydrosulfite, said alkali carbonate is potassium carbonate and said precipitating agent contains about 50 to 70% by weight sodium hydrosulfite, 15 to 40% by weight aluminum powder and 10 to 15% by weight potassium carbonate.
Claim 22
Dependent Claim
25 words
The method of claim 15 wherein said solution is a cyanide solution and further including maintaining said solution at a pH of 12 or higher.
Claim 23
Dependent Claim
15 words
The precipitating agent of claim 2 further including as an activator an alkali metal carbonate.
Claim 24
Dependent Claim
12 words
The precipitating agent of claim 21 wherein said activator is potassium carbonate.
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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) | 1981-05-29 | 1981-11-28 | 1982-05-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-05-29 | 1985-11-28 | 1986-05-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-05-29 | 1989-11-28 | 1990-05-30 | $7700.00 | Window Closed / Lapsed |