US3992197A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Silver crystals and production thereof
Assignee: Individual
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Filing: 1975-03-18
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Granted: 1976-11-16
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Expires: 1995-03-18
Abstract
Abstract Thin flat hexagonal silver crystals are formed by rapidly mixing at a temperature of 30°-80° C., a water solution of inorganic silver salt containing a chelating agent for ferric iron with a water solution of ferrous sulfate containing sulfuric acid and additional chelating agent. The preferred chelating agent is phosphoric acid, and the crystals which are formed are stabilized by the addition of a protective colloid such as polyvinyl alcohol.
Inventors
- 👤 Paul W. Wetzold
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 19:08
CPC Classifications
C; C22; C22B; C22B11/00; C22B11/04; B; B22; B22F; B22F9/00; B22F9/16; B22F9/18; B22F9/24; C01; C01G; C01G5/00; C01G5/003; C09; C09D; C09D5/00; C09D5/38; C22B3/00; C22B3/20; C22B3/26; C22B3/262; C30; C30B; C30B7/00; C30B7/14; Y; Y02; Y02P; Y02P10/00; Y02P10/20; Y10; Y10S; Y10S75/00; Y10S75/954
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
82 words
A method of producing thin flat crystals of silver comprising rapidly mixing with agitation and at a temperature in the range of 30° -80° C. a water solution of a soluble inorganic silver salt containing a chelating agent for ferric iron with a water solution of ferrous sulfate containing sulfuric acid and additional chelating agent for ferric iron, thereby causing thin flat crystals of silver to form, and promptly stabilizing the crystals which are formed by the addition of a protective colloid.
Claim 2
Independent Claim
82 words
A method of producing thin flat crystals of silver comprising rapidly mixing with agitation and at a temperature in the range of 30° -80° C. a water solution of a soluble inorganic silver salt containing a chelating agent for ferric iron with a water solution of ferrous sulfate containing sulfuric acid and additional chelating agent for ferric iron, thereby causing thin flat crystals of silver to form, and promptly stabilizing the crystals which are formed by the addition of a protective colloid.
Claim 3
Dependent Claim
15 words
A method as recited in claim 1 in which said chelating agent is phosphoric acid.
Claim 4
Dependent Claim
15 words
A method as recited in claim 1 in which said silver salt is silver nitrate.
Claim 5
Dependent Claim
61 words
A method as recited in claim 1 in which said silver salt is silver nitrate, said chelating agent is phosphoric acid and a small amount of said silver salt solution is added to said ferrous sulfate solution to cause the production of seed nuceli, whereupon the balance of said silver salt solution is added rapidly to the seeded ferrous sulfate solution.
Claim 6
Dependent Claim
25 words
A method as recited in claim 4 in which said nitric acid is added to said silver salt solution to prevent formation of silver phosphate.
Claim 7
Dependent Claim
23 words
A method as recited in claim 5 in which said solutions are maintained at a temperature in the range of 45° -65° C.
Claim 8
Dependent Claim
15 words
A method as recited in claim 1 in which said protective colloid is polyvinyl alcohol.
Claim 9
Dependent Claim
83 words
A method as recited in claim 1 in which silver salt solution contains, per 1000 ml of distilled water, 1-50 grams of silver nitrate and from 1-50 ml of phosphoric acid, said ferrous sulfate solution contains, per 1000 ml of distilled water, from 5-1000 grams of ferrous sulfate (measured as though it were the heptahydrate), from 20-200 ml of sulfuric acid, and from 1-50 ml of phosphoric acid, and the two solutions are combined in a volumetric ratio of from 1:3 to 3:1.
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) | 1979-11-16 | 1980-05-17 | 1980-11-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-11-16 | 1984-05-17 | 1984-11-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-11-16 | 1988-05-17 | 1988-11-16 | $7700.00 | Window Closed / Lapsed |