US5470525A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Removal of binder from Ta products
Assignee: H.C. Starck GmbH
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Filing: 1994-07-01
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Granted: 1995-11-28
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Expires: 2014-07-01
Abstract
Abstract Tantalum anode pellets or tantalum powders are treated to remove carbon content (mostly attributable to binders used in pressing the powders to pellet form and/or sintering of the pellets) by an aqueous leach at 50°-200° F. in lieu of the conventional complex distillation/decomposition methods.
Inventors
- 👤 Terrance B. Tripp
- 👤 Malcolm Shaw
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 22:29
CPC Classifications
H; H01; H01G; H01G9/00; H01G9/15; B; B22; B22F; B22F1/00; B22F1/14; B22F1/145; B22F3/00; B22F3/10; B22F3/1017; B22F3/1021; B22F3/1025
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
68 words
Process of recovery of binder-pressed tantalum pellets with 0.1-3.0 w/o of a carbonaceous binder comprising the step of contacting the pellets at temperatures of 50°-200° F. with aqueous leach liquor and leaching sufficiently to remove at least 95% by weight of binder-source carbon content thereof while maintaining oxygen content of the pellet substantially constant, the said reduction of carbon content being achieved without heating for distillation/decomposition of binder.
Claim 2
Dependent Claim
68 words
Process of recovery of binder-pressed tantalum pellets with 0.1-3.0 w/o of a carbonaceous binder comprising the step of contacting the pellets at temperatures of 50°-200° F. with aqueous leach liquor and leaching sufficiently to remove at least 95% by weight of binder-source carbon content thereof while maintaining oxygen content of the pellet substantially constant, the said reduction of carbon content being achieved without heating for distillation/decomposition of binder.
Claim 3
Dependent Claim
14 words
Process in accordance with claim 1 wherein the leachant is an aqueous detergent solution.
Claim 4
Dependent Claim
11 words
Process in accordance with claim 1 wherein the leachant is water.
Claim 5
Dependent Claim
28 words
Process in accordance with claim 1 wherein the leaching is carried out for over an hour and sufficiently long to remove 95 w/o of the carbon content thereof.
Claim 6
Dependent Claim
16 words
Process in accordance with claim 1 wherein the pellets are placed in a column and leached.
Claim 7
Dependent Claim
19 words
Process in accordance with claim 1 wherein the pellets are placed in a bath to achieve leaching and rinsing.
Claim 8
Dependent Claim
84 words
A process for treatment of tantalum from binder-pressed-and-double-sintered anode pellets for removal of binder source carbon therefrom without material oxygen pickup in the course of carbon removal, the process comprising the steps of contacting the pellet with an aqueous leach liquor and maintaining the pellet in contact with the leach liquor at 50°-200° F. and sufficiently long to remove at least 95 weight percent of binder carbon content thereof such steps being essentially the only steps undertaken to effect such reduction of carbon content.
Claim 9
Dependent Claim
84 words
A process for treatment of tantalum from binder-pressed-and-double-sintered anode pellets for removal of binder source carbon therefrom without material oxygen pickup in the course of carbon removal, the process comprising the steps of contacting the pellet with an aqueous leach liquor and maintaining the pellet in contact with the leach liquor at 50°-200° F. and sufficiently long to remove at least 95 weight percent of binder carbon content thereof such steps being essentially the only steps undertaken to effect such reduction of carbon content.
Claim 10
Dependent Claim
19 words
A process in accordance with either of claims 1 or 7 wherein the binder consists essentially of stearic acid.
Claim 11
Dependent Claim
23 words
A process in accordance with either of claims 1 or 7 wherein the sinter steps of pellet manufacture are conducted below 1,600° C.
Claim 12
Dependent Claim
18 words
A process as in either of claims 1 or 7 wherein the binder consists essentially of ammonium bicarbonate.
Claim 13
Dependent Claim
17 words
A process as in either of claims 1 or 7 wherein the binder consists essentially of carbowax.
Claim 14
Dependent Claim
38 words
A process as in either of claims 1 or 7 wherein the binder consists essentially of a material selected from the group consisting of fatty acids and their salts, alcohols, molybdenum sulfide, rosin acids, sulfonic acid and carbohydrates.
Claim 15
Dependent Claim
27 words
A process as in either of claims 1 or 7 wherein the pellets are treated for binder removal with an anode lead wire attached to the pellet.
References Cited (Backward Citations)
US5059388A
Cited
US5082491A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1998-11-27 | 1999-05-29 | 1999-11-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-11-27 | 2003-05-29 | 2003-11-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-11-27 | 2007-05-29 | 2007-11-28 | $7700.00 | Window Closed / Lapsed |