Patent US4042671A successfully refreshed from Google Patents.
US4042671A
Expired / Lapsed
US
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Process for leaching sand or other particulate material
Assignee: Individual
•
Filing: 1975-07-10
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Granted: 1977-08-16
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Expires: 1995-07-10
Abstract
Abstract A process for leaching sand to remove iron and other undesirable components in which the sand is treated with a series of leaching solutions which increase in acid concentration to about the midpoint of the process followed by decrease in concentration to a final wash water with the initial drainage from the sand mass being discarded while subsequent drainages are re-used for subsequent leaching operations with the addition of leaching acid to some of the drainage to provide the desired acid concentration.
Inventors
- 👤 Frank W. Bowdish
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 23:43
CPC Classifications
C; C04; C04B; C04B33/00; C04B33/02; C04B33/13; C03; C03C; C03C1/00; C03C1/02; C03C1/022; C04B35/00; C04B35/01; C04B35/14
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
170 words
A process for leaching iron and other metallic compounds from sand with a series of aqueous solutions of differing compositions differing in concentrations of leaching component in the form of an acid, in which the aqueous solutions are fed to the top of the mass of the sand and permitted to drain through gravitationally with appropriate periods of time between solutions for reaction, said solutions of differing compositions forming series which begin with solutions low in concentration of the leaching component and continue with solutions of higher concentration of the leaching component until the solution of highest strength in the series has been reached at about midway through the leaching operation, after which solutions of progressively lower concentrations follow until the series of solutions terminate with one low in concentration of the leaching component, ending with a wash water, said solutions, except for the wash water, being made up largely of the drainage from a previous batch leach, to some of which leaching component is added to increase the concentration.
Claim 2
Dependent Claim
170 words
A process for leaching iron and other metallic compounds from sand with a series of aqueous solutions of differing compositions differing in concentrations of leaching component in the form of an acid, in which the aqueous solutions are fed to the top of the mass of the sand and permitted to drain through gravitationally with appropriate periods of time between solutions for reaction, said solutions of differing compositions forming series which begin with solutions low in concentration of the leaching component and continue with solutions of higher concentration of the leaching component until the solution of highest strength in the series has been reached at about midway through the leaching operation, after which solutions of progressively lower concentrations follow until the series of solutions terminate with one low in concentration of the leaching component, ending with a wash water, said solutions, except for the wash water, being made up largely of the drainage from a previous batch leach, to some of which leaching component is added to increase the concentration.
Claim 3
Dependent Claim
23 words
A process as claimed in claim 1 in which the batches of sand to be leached are retained by a vertically disposed wall.
Claim 4
Dependent Claim
28 words
A process as claimed in claim 2 in which the walls retaining the sand mass have one or more access openings for removal of the sand after leaching.
Claim 5
Dependent Claim
25 words
A process as claimed in claim 3 in which the openings in the retaining wall will admit earth moving equipment to remove the leached sand.
Claim 6
Dependent Claim
24 words
A process as claimed in claim 2 in which the walls are protected with a material that is resistant to the acidic leaching solution.
Claim 7
Dependent Claim
44 words
A process as claimed in claim 1 in which the base on which the sand rests comprises drainage pipes to facilitate the removal of drained solution and in which the base is supported on an impervious layer to avoid the loss of said solutions.
Claim 8
Dependent Claim
20 words
A process as claimed in claim 6 in which steam is injected through the pipes used for drainage of solution.
Claim 9
Dependent Claim
44 words
A process as claimed in claim 1 in which the drainage solutions for each leach batch are collected and segregated into different portions for removal of the first increments from the system and for re-use of the other increments in a subsequent leach operation.
Claim 10
Dependent Claim
44 words
A process as claimed in claim 8 in which part of the drainage solution is removed from the system as product and as discard in order to avoid an undesirable buildup of dissolved matter in the solutions to be used in subsequent batch leaches.
Claim 11
Dependent Claim
16 words
A process as claimed in claim 1 in which the leaching component is an inorganic acid.
Claim 12
Dependent Claim
26 words
A process as claimed in claim 10 in which the inorganic acid is selected from the group consisting of HCl and H 2 SO 4 .
Claim 13
Dependent Claim
30 words
A process as claimed in claim 1 in which prior to leaching steam is injected into the sand mass in order to raise the sand to elevated temperature for reaction.
Claim 14
Dependent Claim
29 words
A process as claimed in claim 12 in which the steam is injected into the sand mass from the bottom side for passage upwardly through the mass of sand.
Claim 15
Dependent Claim
24 words
A process as claimed in claim 1 in which the and and/or solutions is heated for carrying out the leaching operation at elevated temperature.
Claim 16
Dependent Claim
45 words
A process as claimed in claim 1 in which each batch of sand to be leached is piled on a base of gravel, pebbles, broken rock, coarse sand or other coarse particulate material to facilitate drainage of the solution through and from the sand pile.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-08-15 | 1981-02-14 | 1981-08-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-08-15 | 1985-02-14 | 1985-08-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-08-15 | 1989-02-14 | 1989-08-16 | $7700.00 | Window Closed / Lapsed |