Patent US3672579A successfully refreshed from Google Patents.
US3672579A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for beneficiating magnetite iron ore
Assignee: University of Minnesota Twin Cities
•
Filing: 1970-08-10
•
Granted: 1972-06-27
•
Expires: 1990-08-10
Abstract
Abstract A process for upgrading low-grade magnetite-containing iron ore with minimum fine grinding. The dry ore is first comminuted to between about three-fourths inch and 10 mesh particle size and magnetically separated. The dry tailing is discarded and the concentrate is ground to between about 20 and 100 mesh and again subjected to dry magnetic separation. The dry tailing is again discarded and the concentrate is then finely ground according to conventional practice and subjected to wet magnetic separation. About 90 percent or more of the tailing is discarded dry without fine grinding, permitting easy disposal without possible ecological damage due to lake and stream pollution.
Inventors
- 👤 James E Lawver
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 18:44
CPC Classifications
C; C01; C01G; C01G49/00; C01G49/02; C01G49/08; B; B03; B03C; B03C1/00; B03C1/005; C01P; C01P2004/00; C01P2004/60; C01P2004/61
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
56 words
A process according to claim 1 further characterized in that: A. said initial concentrate resulting from said first dry magnetic separation is composed of a plurality of fractions, B. said concentrate fractions are separately further crushed and subjected to further dry magnetic separation, and C. the resulting further intermediate concentrate fractions are combined for further processing.
Claim 2
Dependent Claim
49 words
A process according to claim 1 further characterized in that: A. said finely ground concentrate is subjected sequentially to a plurality of wet magnetic separations each producing a tailing and a further upgraded concentrate, B. each of said tailings is discarded, and C. said final high-grade concentrate is recovered.
Claim 3
Dependent Claim
17 words
A process according to claim 1 further characterized in that said low-grade magnetite iron ore is taconite.
Claim 4
Dependent Claim
23 words
A process according to claim 1 further characterized in that said last named wet tailing is pumped to a dry land tailing pond.
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) | 1975-06-27 | 1975-12-27 | 1976-06-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-06-27 | 1979-12-27 | 1980-06-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-06-27 | 1983-12-27 | 1984-06-27 | $7700.00 | Window Closed / Lapsed |