US3644094A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for the recovery of diamond particles from alumina or silicate wastes
Assignee: Earth Sciences Inc
•
Filing: 1970-02-16
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Granted: 1972-02-22
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Expires: 1990-02-16
Abstract
Abstract Alumina wastes, and various silicate wastes, produced by grinding ceramic workpieces with diamond impregnated wheels are intermixed with a borax flux and heated in a nonoxidizing atmosphere to produce a fluid melt of the alumina and flux. The melt or resulting solid phase is then acid treated to dissolve and liquefy the alumina or silicate contents and the resulting liquor is drawn off leaving the particulate fraction which contains the desired diamond particles.
Inventors
- 👤 Douglas N Stevens
- 👤 Ramond E Bisque
- 👤 Duane N Bloom
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 14:52
CPC Classifications
C; C01; C01F; C01F7/00; C01F7/02; C01F7/34
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
17 words
A process as described in claim 1 in which the alkali metal borate comprises: a. borax Na2B4O71OH2O.
Claim 2
Dependent Claim
26 words
A process as described in claim 1 in which the intermixed wastes and flux are: a. heated to a temperature of from 700* to 1,000* C.
Claim 3
Dependent Claim
64 words
A process as described in claim 1 in which: a. The residual liquor drawn from the acid bath is treated with an acid to change its pH value sufficiently to precipitate and recover the alumina therefrom as a hydroxide, A1(OH)3, and in which b. the remaining liquor is processed by evaporation to recover the flux for recycling with additional agglomerate mixture through the process.
Claim 4
Dependent Claim
54 words
A process as described in claim 1 in which: a. the addition of the sodium fluoride (NaF) produces a floatable scum on the melt containing a concentrate of the major solid phase materials; and b. in which the said scum is physically separated from the melt for initial recovery of the solid phase materials.
Claim 5
Dependent Claim
112 words
A process for recovering diamond particles from an agglomerate mixture of alumina or corundum wastes comprising: a. removing organic materials from said mixture; b. physically milling the cleaned mixture to a substantially uniformly sized aggregate; c. intimately incorporating a borate flux, containing sodium fluoride, with said agglomerate mixture; d. heating the fluxed mixture in a substantially nonoxidizing atmosphere to 700*-1,000* C. to produce a glassy liquid melt containing solid diamond particles; e. cooling the melt to form a glassy solid with the solid diamond particles concentrated at the surface thereof; and f. dissolving and washing the latter concentrate from the surface of the glassy solid for the recovery of the solid particles.
Claim 6
Dependent Claim
42 words
A process as described in claim 6 including: a. dissolving the cooled glassy solid in an acid bath; and b. varying the pH value of the acid bath to precipitate the alumina therefrom as hydrated aluminum hydroxide for reuse in the process.
Claim 7
Dependent Claim
26 words
A process as described in claim 7 including: a. recovering, by evaporation the remaining precipitant liquor, of the sodium borates from the acid bath for reuse.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-02-21 | 1975-08-23 | 1976-02-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-02-21 | 1979-08-23 | 1980-02-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-02-21 | 1983-08-23 | 1984-02-22 | $7700.00 | Window Closed / Lapsed |