US4860957A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Treatment of middlings
Assignee: Individual
•
Filing: 1988-03-29
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Granted: 1989-08-29
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Expires: 2008-03-29
Abstract
Abstract Regrinding of middlings in a mineral-product dressing process of the kind in which the middlings are reground in order to crush individual half-grains and release valuable mineral therefrom, is carried out in a mill using an agitated grinding medium. The middlings are reduced to a particle size which is smaller than k 80 =100 mm. There are used grinding bodies having originally a size of from 2 to 12 mm.
Inventors
- 👤 Lars Lidstrom
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 07:14
CPC Classifications
B; B02; B02C; B02C17/00; B02C17/18; B02C17/20
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
157 words
A method for dressing a mineral product comprising the steps of: providing a finely divided mineral product to a concentration zone, said finely divided mineral product having a particle size suitable for a dressing treatment; subjecting said finely divided mineral product to a dressing treatment in said concentration zone, said dressing treatment comprising at least two stages and being selected from the group consisting of flotation separation processes and magnetic separation processes; recovering middlings formed during said dressing treatment; grinding said middlings in a mill containing an agitated grinding medium with the aid of grinding bodies having an original size of from 2 to 12 mm to produce ground middlings having a particle size smaller than k 80 =100 μm, said middlings being ground in order to crush individual half-grains of said middlings and release valuable mineral therefrom; and then passing said ground middlings to said concentration zone and subjecting said ground middlings to said dressing treatment.
Claim 2
Independent Claim
157 words
A method for dressing a mineral product comprising the steps of: providing a finely divided mineral product to a concentration zone, said finely divided mineral product having a particle size suitable for a dressing treatment; subjecting said finely divided mineral product to a dressing treatment in said concentration zone, said dressing treatment comprising at least two stages and being selected from the group consisting of flotation separation processes and magnetic separation processes; recovering middlings formed during said dressing treatment; grinding said middlings in a mill containing an agitated grinding medium with the aid of grinding bodies having an original size of from 2 to 12 mm to produce ground middlings having a particle size smaller than k 80 =100 μm, said middlings being ground in order to crush individual half-grains of said middlings and release valuable mineral therefrom; and then passing said ground middlings to said concentration zone and subjecting said ground middlings to said dressing treatment.
Claim 3
Dependent Claim
23 words
A method according to claim 1, wherein said middlings are ground at an energy input of at most 20 kWh/t of dry middlings.
Claim 4
Dependent Claim
38 words
A method according to claim 1, wherein the grinding medium grinding bodies are composed of an autogenous material which comprises a fraction selected from the material to be dressed, or of a material which is rich in silicon.
Claim 5
Dependent Claim
24 words
A method according to claim 3, wherein the grinding medium grinding bodies comprise a material selected from the group consisting of quartz and olivine.
Claim 6
Dependent Claim
35 words
A method according to claim 1, further comprising the step of subjecting the ground middlings to a separating treatment to remove undesirable grinding-medium residues therefrom, prior to passing the ground middlings to said concentration zone.
Claim 7
Dependent Claim
15 words
A method according to claim 1, wherein the middlings are ground in a wet environment.
Claim 8
Dependent Claim
15 words
A method according to claim 6, wherein said dressing treatment comprises a flotation separation process.
Claim 9
Dependent Claim
15 words
A method according to claim 1, wherein the grinding medium bodies comprise sintered hard metal.
Claim 10
Dependent Claim
15 words
A method according to claim 8, wherein the grinding medium bodies comprise sintered tungsten carbide.
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) | 1992-08-28 | 1993-02-27 | 1993-08-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-08-28 | 1997-02-27 | 1997-08-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-08-28 | 2001-02-27 | 2001-08-29 | $7700.00 | Window Closed / Lapsed |