US3595484A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Reclamation of refractory carbides from carbide materials
Assignee: Individual
•
Filing: 1969-02-28
•
Granted: 1971-07-27
•
Expires: 1989-02-28
Abstract
Abstract Refractory carbides, particularly tungsten carbide, are reclaimed from cemented carbides by treating the cemented carbide with molten zinc and subsequently distilling the zinc from the mass. The zinc forms an alloy with the cementing agent, usually cobalt, thereby dissolving the carbide-cementing agent bond and permitting recovery of a mixture of the carbide and the cementing agent in a form that can be reused in preparation of cemented carbides.
Inventors
- 👤 Paul G Barnard
- 👤 Heine Kenworthy
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 02:56
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/515; C04B35/56; C01; C01B; C01B32/00; C01B32/90; C01B32/914; C01B32/949
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
15 words
The method of claim 1 in which the refractory carbide consists essentially of tungsten carbide.
Claim 2
Dependent Claim
15 words
The method of claim 1 in which the refractory carbide consists essentially of tungsten carbide.
Claim 3
Dependent Claim
12 words
The method of claim 1 in which the cementing agent is cobalt.
Claim 4
Dependent Claim
12 words
The method of claim 1 in which the cementing agent is cobalt.
Claim 5
Dependent Claim
29 words
The method of claim 1 in which the temperature and time of the treatment with molten zinc are about 750* to 800* C. and 3 to 2 hours, respectively.
Claim 6
Dependent Claim
35 words
The method of claim 1 in which the distillation of the zinc is carried out at a temperature of about 700* to 800* C. and under a partial vacuum of about 10 to 50 microns.
Claim 7
Dependent Claim
38 words
The method of claim 1 in which the resulting mass is subsequently cooled to room temperature in an inert atmosphere or in a vacuum and then ground to a powder for reuse in preparation of a cemented carbide.
Claim 8
Dependent Claim
187 words
The method of claim 1 in which the resulting mass is subsequently cooled to room temperature in an inert atmosphere or in a vacuum and then ground to a powder for reuse in preparation of a cemented carbide. The apparatus employed was of the type shown in the drawings and was heated by electrical resistance. 450 grams of cemented carbide reject scrap having a particle size of 1/2 to 1 micron and a composition of 94 percent tungsten carbide and 6 percent cobalt were treated with an equal weight of zinc at 800*C. for 2 hours in an atmosphere of helium (provided via vacuum line). The zinc was then distilled off in 6 hours at 800*C. under a pressure of 10-50 microns. The zinc vapors were collected in the cooler portion of the furnace, resulting in 99.9 percent recovery of the zinc. In this example the procedure and results were essentially the same as those of example 1, except that the cemented carbide reject scrap consisted of 72 percent tungsten carbide, 12 percent tantalum carbide, 8 percent titanium carbide and 8 percent cobalt. What We claim is:
References Cited (Backward Citations)
GB582921A
Cited
US3515540A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-07-26 | 1975-01-25 | 1975-07-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-07-26 | 1979-01-25 | 1979-07-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-07-26 | 1983-01-25 | 1983-07-27 | $7700.00 | Window Closed / Lapsed |