Patent US3885955A successfully refreshed from Google Patents.
US3885955A
Expired / Lapsed
US
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Process for the production of gold powder
Assignee: Demetron Gesellschaft fuer Elektronik Werkstoffe mbH
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Filing: 1974-06-10
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Granted: 1975-05-27
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Expires: 1994-06-10
Abstract
Abstract Gold powder of different predeterminable particle size, particle shapes and specific surface area predeterminable by the choice of reaction conditions is obtained by precipitation of chloroauric (III) acid with ammonia from an aqueous hydrochloric acid solution and reducing the precipitate as a suspension with a reducing agent.
Inventors
- 👤 Klaus Lutz
- 👤 Manfred Golla
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 12:17
CPC Classifications
C; C22; C22B; C22B11/00; C22B11/04; Y; Y10; Y10S; Y10S75/00; Y10S75/952
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
56 words
A PROCESS OF PREPARING GOLD POWDER OF PREDETERMINED PARTICLES SIZE, PARTICLE SHAPE AND SPECIFIC SURFACE AREA COMPRISI ING PRECIPITATING CHLOROACURIC III ACID FROM AN AQUEOUS HYDROCHLORIC ACID SOLUTION THEREOF WITH AMMONIA, PREPARING A SUSPENSION OF THE PRECIPITATE IN A LIQUID WITHOUT DRYING AND REDUCING THE GOLD IN SAID SUSPENSION TO FREE METAL WITH A REDUCING AGENT.
Claim 2
Dependent Claim
56 words
A PROCESS OF PREPARING GOLD POWDER OF PREDETERMINED PARTICLES SIZE, PARTICLE SHAPE AND SPECIFIC SURFACE AREA COMPRISI ING PRECIPITATING CHLOROACURIC III ACID FROM AN AQUEOUS HYDROCHLORIC ACID SOLUTION THEREOF WITH AMMONIA, PREPARING A SUSPENSION OF THE PRECIPITATE IN A LIQUID WITHOUT DRYING AND REDUCING THE GOLD IN SAID SUSPENSION TO FREE METAL WITH A REDUCING AGENT.
Claim 3
Dependent Claim
16 words
A process according to claim 1, wherein the suspension liquid comprises water and/or a glycol ether.
Claim 4
Dependent Claim
19 words
A process according to claim 2, wherein the solvent is a mixture of water and ethylene glycol monoethyl ether.
Claim 5
Dependent Claim
19 words
A process according to claim 2, wherein the chloroauric III acid containing solution contains 2-15 percent free hydrochloric acid.
Claim 6
Dependent Claim
15 words
A process according to claim 4 wherein said solution contains 5-10 percent of hydrochloric acid.
Claim 7
Dependent Claim
17 words
A process according to claim 2, wherein the reducing agent is sulfur dioxide, hydroxylamine, hydrazine or triethanolamine.
Claim 8
Dependent Claim
37 words
A process according to claim 2, for the production of gold powder in the form of 5-10 Mu m spheres comprising employing water as the suspension liquid and sulfur dioxide as the reducing agent at room temperature.
Claim 9
Dependent Claim
44 words
A process according to claim 2, for the production of gold powder in the form of 1-10 Mu m crystallites comprising employing a water-ethylene glycol monoethyl ether mixture as the suspension liquid and hydroxylamine as the reducing agent at a temperature of 50*to 90*C.
Claim 10
Dependent Claim
46 words
A process according to claim 2 for the production of gold powder having a particle size of not over 1 Mu m comprising employing a water-ethylene glycol monoethyl ether mixture as the suspension liquid and triethanolamine as the reducing agent at a temperature of about 100*C.
Claim 11
Dependent Claim
45 words
A process according to claim 2, for the production of gold powder in the form of fine fibers comprising employing a water-ethylene glycol monoethyl ether mixture acidified to a pH of 1-4 as the suspension liquid and triethanolamine as the reducing agent at about 100*C.
Claim 12
Dependent Claim
37 words
A process according to claim 2 for the production of gold powder with a specific Surface area between 3 and 5 m2/g comprising employing water as the suspension liquid and hydrazine as the reducing agent at 50*-70*C.
Claim 13
Dependent Claim
37 words
A process according to claim 2 wherein there is added a reducible salt of a metal other than gold to the gold suspension and there is formed in the reduction a mixture of gold and other metal.
Claim 14
Dependent Claim
11 words
A process according to claim 12, wherein said metal is silver.
Claim 15
Dependent Claim
13 words
A process according to claim 12 wherein the metal salt is silver nitrate.
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) | 1978-05-26 | 1978-11-25 | 1979-05-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-05-26 | 1982-11-25 | 1983-05-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-05-26 | 1986-11-25 | 1987-05-27 | $7700.00 | Window Closed / Lapsed |