US4053113A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Dry grinding process for reducing ore to pelletizable particles
Assignee: GEA Group AG
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Filing: 1976-09-24
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Granted: 1977-10-11
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Expires: 1996-09-24
Abstract
Abstract A dry grinding process for reducing ore to pelletizable particles comprises grinding the ore in a size-reducing unit and classfiying the ore in a centrifugal pneumatic separator which is automatically controlled to make the coarse fraction available at a substantially constant rate. The coarse fraction is recycled to the size-reducing unit and the total rate of fed ore and recycled coarse fraction is maintained substantially constant. The ore-feeding rate is varied when, and only when, a controlled variable of the pneumatic separator has a deviation in excess of a predetermined permissible deviation.
Inventors
- 👤 Friedrich Rosenstock
- 👤 Walter Hastik
- 👤 Reinhold Becker
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 13:53
CPC Classifications
B; B02; B02C; B02C25/00
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
152 words
A process for dry grinding ore to produce pelletizable particles which comprises the steps of: a. grinding ore in a size-reducing unit; b. classifying the ground ore in a centrifugal pneumatic separator into a coarse fraction and a fine fraction, said centrifugal pneumatic separator having a controllable operating parameter; c. recycling the coarse fraction into the size-reducing unit; d. discharging the fine fraction as a finished product; and e. maintaining a substantially constant total rate of ore feed and recycled coarse fraction feed to said size-reducing unit by maintaining the ratio of the ore-feed rate to the coarse fraction recycled rate substantially constant, automatically controlling the centrifugal pneumatic separator to make said coarse fraction available with a varying particle size fraction at a substantially constant rate, and varying the ore-feed rate when and only when, said controllable variable of the pneumatic separator has a deviation in excess of a predetermined permissible deviation.
Claim 2
Dependent Claim
152 words
A process for dry grinding ore to produce pelletizable particles which comprises the steps of: a. grinding ore in a size-reducing unit; b. classifying the ground ore in a centrifugal pneumatic separator into a coarse fraction and a fine fraction, said centrifugal pneumatic separator having a controllable operating parameter; c. recycling the coarse fraction into the size-reducing unit; d. discharging the fine fraction as a finished product; and e. maintaining a substantially constant total rate of ore feed and recycled coarse fraction feed to said size-reducing unit by maintaining the ratio of the ore-feed rate to the coarse fraction recycled rate substantially constant, automatically controlling the centrifugal pneumatic separator to make said coarse fraction available with a varying particle size fraction at a substantially constant rate, and varying the ore-feed rate when and only when, said controllable variable of the pneumatic separator has a deviation in excess of a predetermined permissible deviation.
Claim 3
Dependent Claim
28 words
The process defined in claim 1 wherein the automatic control of the centrifugal pneumatic separator is effected by changing the speed of a fan of said pneumatic separator.
Claim 4
Dependent Claim
44 words
The process defined in claim 1 wherein the permissible deviation of he controllable variable of the centrifugal pneumatic separator is the permissible deviation of the particle size spectrum of the finished product and the ore-feed rate is changed when this permissible deviation is exceeded.
Claim 5
Dependent Claim
21 words
The process defined in claim 1 wherein the ore-feed rate is changed in steps when the permissible deviation has been exceeded.
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) | 1980-10-10 | 1981-04-11 | 1981-10-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-10-10 | 1985-04-11 | 1985-10-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-10-10 | 1989-04-11 | 1989-10-11 | $7700.00 | Window Closed / Lapsed |