US4251352A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Inclined separation screen for agitation tank
Assignee: Bechtel Group Inc
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Filing: 1979-12-28
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Granted: 1981-02-17
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Expires: 1999-12-28
Abstract
Abstract An improvement in the screen circumscribing or partially circumscribing the rim of an agitation tank is disclosed. A screen substantially impermeable to the charcoal is provided which is inclined inwardly at an angle between about 35° and 55° from vertical. The metal-bearing charcoal adhering to the screen is readily washed from the screen by the rolling motion of the mixture in the tank.
Inventors
- 👤 Robert S. Shoemaker
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 21:23
CPC Classifications
C; C22; C22B; C22B3/00; C22B3/02; B; B01; B01D; B01D15/00; B01D15/02; B01D35/00; B01D35/22; B07; B07B; B07B1/00; B07B1/46; B07B1/50; C22B3/20; C22B3/22; C22B3/24; Y; Y02; Y02P; Y02P10/00; Y02P10/20
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
116 words
In an agitated tank in which a mixture of precious metal-adsorbing charcoal and a ground ore pulp is agitated within the tank by imparting a rolling motion to the mixture, the metal-adsorbing charcoal being retained in the tank and the pulp being expelled over the rim of the tank, the improvement comprising a screen substantially impermeable to the charcoal at least partially circumscribing the rim of the tank and inclined inwardly at an angle of between about 35° and 55° from vertical so that the metal-adsorbing charcoal is washed from the screen by the rolling motion of the mixture in the tank and abrasion of the charcoal against the screen causing loss of charcoal is minimized.
Claim 2
Dependent Claim
116 words
In an agitated tank in which a mixture of precious metal-adsorbing charcoal and a ground ore pulp is agitated within the tank by imparting a rolling motion to the mixture, the metal-adsorbing charcoal being retained in the tank and the pulp being expelled over the rim of the tank, the improvement comprising a screen substantially impermeable to the charcoal at least partially circumscribing the rim of the tank and inclined inwardly at an angle of between about 35° and 55° from vertical so that the metal-adsorbing charcoal is washed from the screen by the rolling motion of the mixture in the tank and abrasion of the charcoal against the screen causing loss of charcoal is minimized.
Claim 3
Dependent Claim
20 words
The agitation tank of claim 1 wherein the screen is inclined inwardly at an angle of substantially 45° from vertical.
Claim 4
Dependent Claim
33 words
The agitation tank of claim 1 wherein the screen comprises a plurality of trapezoidal screen sections, each of which is inclined inwardly at an angle of between about 35° and 55° from vertical.
Claim 5
Dependent Claim
31 words
The agitation tank of claim 1 wherein the screens are approximately 28 mesh, the charcoal is substantially 12×20 mesh, and the ore in the pulp is no larger than 48 mesh.
Claim 6
Dependent Claim
14 words
The agitation tank of claim 1 wherein agitation is provided solely by forced air
Claim 7
Dependent Claim
13 words
The agitation tank of claim 1 wherein the tank is a pachuca tank.
Claim 8
Dependent Claim
131 words
In an agitated tank in which a mixture of precious metal-adsorbing charcoal and a ground ore pulp is agitated within the tank by imparting a rolling motion to the mixture, the charcoal being retained in the tank and the pulp being expelled over the rim of the tank, the improvement comprising a plurality of screen sections joined together to form a continuous screen substantially impermeable to the charcoal and at least partially circumscribing the rim of the tank, each screen section being inclined inwardly at an angle of between about 35° and 55° from vertical, so that the metal-adsorbing charcoal is washed from the screen by the rolling motion of the mixture in the tank and abrasion of the charcoal against the screen causing loss of the metal-adsorbing charcoal is minimized.
Claim 9
Dependent Claim
131 words
In an agitated tank in which a mixture of precious metal-adsorbing charcoal and a ground ore pulp is agitated within the tank by imparting a rolling motion to the mixture, the charcoal being retained in the tank and the pulp being expelled over the rim of the tank, the improvement comprising a plurality of screen sections joined together to form a continuous screen substantially impermeable to the charcoal and at least partially circumscribing the rim of the tank, each screen section being inclined inwardly at an angle of between about 35° and 55° from vertical, so that the metal-adsorbing charcoal is washed from the screen by the rolling motion of the mixture in the tank and abrasion of the charcoal against the screen causing loss of the metal-adsorbing charcoal is minimized.
Claim 10
Dependent Claim
18 words
In claim 7 wherein each screen section is inclined inwardly at an angle of substantially 45° from vertical.
Claim 11
Dependent Claim
28 words
In claim 7 wherein the screens of each section are approximately 28 mesh, the charcoal is substantially 12×20 mesh, and the pulp is no larger than 28 mesh.
Claim 12
Dependent Claim
12 words
In claim 7 wherein the screen sections are flat, trapezoidal screen sections.
Claim 13
Dependent Claim
13 words
In claim 1 or 7 wherein the ground ore pulp includes gold ore.
Claim 14
Dependent Claim
13 words
In claim 1 or 7 wherein the ground ore pulp includes silver ore.
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) | 1984-02-17 | 1984-08-18 | 1985-02-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-02-17 | 1988-08-18 | 1989-02-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-02-17 | 1992-08-18 | 1993-02-17 | $7700.00 | Window Closed / Lapsed |