Patent US4582530A successfully refreshed from Google Patents.
US4582530A
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US
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Method of making a valve metal powder for electrolytic condensers and the like
Assignee: Cabot Corp
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Filing: 1984-08-06
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Granted: 1986-04-15
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Expires: 2004-08-06
Abstract
Abstract In the production of a vanadium group valve metal powder, especially tantalum, the reaction mixture of a double fluoride salt of the valve metal and metallic sodium and/or potassium is doped with sulfur before a melt cake is formed. The melt cake is then leached with water to eliminate central salts leaving the valve metal powder. The sulfur doping provides improved surface area and particle size characteristics.
Inventors
- 👤 Hans J. Heinrich
- 👤 Meinhard Aits
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 19:42
CPC Classifications
H; H01; H01G; H01G9/00; H01G9/004; H01G9/04; H01G9/048; H01G9/052; H01G9/0525; B; B22; B22F; B22F9/00; B22F9/16; B22F9/18; B22F9/20; C; C22; C22B; C22B34/00; C22B34/20; C22B34/24
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
81 words
A method of making a valve metal powder of a metal of the vanadium group of metals of the periodic system which comprises the steps of: forming a reaction mixture of a double fluoride salt of said valve metal and metallic sodium or potassium or both; doping said reaction mixture with an effective amount of sulphur; heating the reaction mixture doped with sulfur to form a melt cake; and leaching water soluble salts from said melt cake to yield said powder.
Claim 2
Independent Claim
81 words
A method of making a valve metal powder of a metal of the vanadium group of metals of the periodic system which comprises the steps of: forming a reaction mixture of a double fluoride salt of said valve metal and metallic sodium or potassium or both; doping said reaction mixture with an effective amount of sulphur; heating the reaction mixture doped with sulfur to form a melt cake; and leaching water soluble salts from said melt cake to yield said powder.
Claim 3
Dependent Claim
11 words
The method defined in claim 1 wherein said metal is tantalum.
Claim 4
Dependent Claim
20 words
The method defined in claim 2 wherein the sulfur is introduced into said mixture in the form of elemental sulfur.
Claim 5
Dependent Claim
14 words
The method defined in claim 3 wherein said elemental sulfur is flowers of sulfur.
Claim 6
Dependent Claim
23 words
The method defined in claim 2 wherein the sulfur is introduced into said reaction mixture in the form of an inorganic sulfur compound.
Claim 7
Dependent Claim
24 words
The method defined in claim 5 wherein said inorganic sulfur compound is selected from the group which consists of sodium sulfate and sodium dithionite.
Claim 8
Dependent Claim
23 words
The method defined in claim 2 wherein the sulfur is added to said reaction mixture in the form of an organic sulfur compound.
Claim 9
Dependent Claim
42 words
The method defined in claim 2 wherein the sulfur is added to said reacton mixture in the form of a mixture of two members selected from the group which consists of elemental sulfate an inorganic sulfur compound and an organic sulfur compound.
Claim 10
Dependent Claim
31 words
The method defined in claim 2 wherein the sulfur is added to said reaction mixture in the form of a compound which can be leached from said cake with said salts.
Claim 11
Dependent Claim
29 words
The method defined in claim 2 wherein the sulfur is added to said reaction mixture in an amount of 50 to 500 ppm sulfur referred to said valve metal.
Claim 12
Dependent Claim
26 words
The method defined in claim 2 wherein the sulfur is added to said reaction mixture by first forming said reaction mixture and then adding sulfur thereto.
Claim 13
Dependent Claim
29 words
The method defined in claim 2 wherein the sulfur is added to said reaction mixture by combining sulfur with said double fluoride salt and then forming the reaction mixture.
Claim 14
Dependent Claim
33 words
The method defined in claim 2 wherein the sulfur is added to said reaction mixture by incorporating it into the double fluoride salt during the mixture thereof and then forming said reaction mixture.
Claim 15
Dependent Claim
20 words
A valve metal powder having improved surface area and reduced particle size as made by the method of claim 1.
References Cited (Backward Citations)
US3647415A
Cited
US3825802A
Cited
US4128421A
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US4009007A
Cited
GB2068924A
Cited
US4356028A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-04-14 | 1989-10-14 | 1990-04-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-04-14 | 1993-10-14 | 1994-04-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-04-14 | 1997-10-14 | 1998-04-15 | $7700.00 | Window Closed / Lapsed |