US4432868A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Separation of high grade magnetite from fly ash
Assignee: Halomet Inc
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Filing: 1981-10-05
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Granted: 1984-02-21
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Expires: 2001-10-05
Abstract
Abstract A unique, high-grade magnetite obtained from fly ash, the use thereof in the cleaning of coal, and low iron content fly ash.
Inventors
- 👤 Robert G. Aldrich
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 19:08
CPC Classifications
C; C01; C01G; C01G49/00; C01G49/02; C01G49/08; B; B03; B03B; B03B5/00; B03B5/28; B03B5/30; B03B5/44; B03B5/447; B03B9/00; B03B9/005; B03C; B03C1/00; C01P; C01P2004/00; C01P2004/01; C01P2004/03; C01P2004/30; C01P2004/32; C01P2004/34; C01P2004/36; C01P2004/60; C01P2004/61; Y; Y10; Y10S; Y10S106/00; Y10S106/01
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
76 words
Magnetite derived from fly ash obtained as a product of coal combustion which comprises an admixture of spherical particles and broken spherical particles, the broken spherical particles being obtained by grinding spherical particles having a size greater than 325 mesh; said magnetite having a percent magnetics of at least about 96% as measured by Davis Tube and a specific gravity of from about 4.1 to about 4.5 and consisting essentially of particles less than 325 mesh.
Claim 2
Dependent Claim
76 words
Magnetite derived from fly ash obtained as a product of coal combustion which comprises an admixture of spherical particles and broken spherical particles, the broken spherical particles being obtained by grinding spherical particles having a size greater than 325 mesh; said magnetite having a percent magnetics of at least about 96% as measured by Davis Tube and a specific gravity of from about 4.1 to about 4.5 and consisting essentially of particles less than 325 mesh.
Claim 3
Dependent Claim
19 words
The magnetite of claim 1 wherein the major portion of the magnetics is in the form of spherical particles.
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) | 1987-02-20 | 1987-08-22 | 1988-02-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-02-20 | 1991-08-22 | 1992-02-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-02-20 | 1995-08-22 | 1996-02-21 | $7700.00 | Window Closed / Lapsed |