Patent US3890425A successfully refreshed from Google Patents.
US3890425A
Expired / Lapsed
US
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Redox treatment of alunite ore
Assignee: Southwire Co LLC
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Filing: 1974-03-21
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Granted: 1975-06-17
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Expires: 1994-03-21
Abstract
Abstract This invention relates to a method for recovering aluminum hydroxide from alunite ore by roasting the ore to remove water of hydration, roasting it again in a reducing atmosphere to remove sulfate, roasting a third time in an oxidizing atmosphere to convert any sulfides formed in the second roast, leaching with water to remove potassium and sulfate, extracting the aluminum content with a mixture of sodium hydroxide and potassium hydroxide, removing contaminant silica from the leach solution, and precipitating aluminum hydroxide by cooling and seeding the solution.
Inventors
- 👤 Douglas Stevens
- 👤 Helge O Forberg
- 👤 Larry D Jennings
- 👤 Jr Frank M Stephens
- 👤 Francis J Bowen
- 👤 David L Thompson
- 👤 Jr Julian V Copenhaver
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 06:28
CPC Classifications
C; C01; C01F; C01F7/00; C01F7/02; C01F7/04; C01F7/06; C01F7/0686
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
126 words
A METHOD FOR RECOVERING ALUMINUM HYDROXIDE AND OTHER VALUABLE CONSTITUENTS FROM ORE CONTAINING ALUNITE, COMPRISING THE STEPS OF: A. ROASTING THE ORE TO REMOVE WATER BY HYDRATION, B. ROASTING THE DEHYDRATED ORE RESULTING FROM STEP (A) IN A REDUCING ATMOSPHERE TO REMOVE SULFATE, C. ROASTING THE REDUCED ORE RESULTING FROM STEP (B) IN AN OXIDIZING ATMOSPHERE TO CONVERT SULFIDES TO SULFUR OXIDES, D. LEACHING THE OXIDIZED ORE RESULTING FROM STEP (C) WITH SOLVENT TO REMOVE POTASSIUM AND SULFATE, E. SEPARATING THE LIQUID AND SOLID PORTIONS OF THE SLURRY RESULTING FROM STEP (D), F. DIGESTING THE SOLID PORTION RESULTING FROM STEP (E) WITH AN AQUEOUS MIXTURE OF ALKALI METAL HYDROXIDES AT A CONCENTRATION AND AT A TEMPERATURE SUFFICIENT TO EXTRACT THE ALUMINUM CONTENT FROM SAID SOLID PORTION,
Claim 2
Independent Claim
126 words
A METHOD FOR RECOVERING ALUMINUM HYDROXIDE AND OTHER VALUABLE CONSTITUENTS FROM ORE CONTAINING ALUNITE, COMPRISING THE STEPS OF: A. ROASTING THE ORE TO REMOVE WATER BY HYDRATION, B. ROASTING THE DEHYDRATED ORE RESULTING FROM STEP (A) IN A REDUCING ATMOSPHERE TO REMOVE SULFATE, C. ROASTING THE REDUCED ORE RESULTING FROM STEP (B) IN AN OXIDIZING ATMOSPHERE TO CONVERT SULFIDES TO SULFUR OXIDES, D. LEACHING THE OXIDIZED ORE RESULTING FROM STEP (C) WITH SOLVENT TO REMOVE POTASSIUM AND SULFATE, E. SEPARATING THE LIQUID AND SOLID PORTIONS OF THE SLURRY RESULTING FROM STEP (D), F. DIGESTING THE SOLID PORTION RESULTING FROM STEP (E) WITH AN AQUEOUS MIXTURE OF ALKALI METAL HYDROXIDES AT A CONCENTRATION AND AT A TEMPERATURE SUFFICIENT TO EXTRACT THE ALUMINUM CONTENT FROM SAID SOLID PORTION,
Claim 3
Dependent Claim
42 words
The method of claim 1 in which Step (a), Step (b) and Step (c) are carried out at a temperature of from about 400*C to about 850*C for a time of from about one-half minute to about six hours for each step.
Claim 4
Dependent Claim
42 words
The method of claim 1 in which Step (a), Step (b) and Step (c) are carried out at a temperature of from about 500*C to about 650*C for a time of from about one-half minute to about six hours for each step.
Claim 5
Dependent Claim
25 words
The method of claim 1 wherein the reducing atmosphere of Step (b) is selected from the group consisting hydrogen, hydrocarbons, carbon monoxide and mixtures thereof.
Claim 6
Dependent Claim
24 words
The method of claim 1 wherein the oxidizing atmosphere of Step (c) is selected from the group consisting of air, oxygen and mixtures thereof.
Claim 7
Dependent Claim
22 words
The method of claim 1 wherein the solvent of Step (d) is selected from the group consisting of water and alkaline solutions.
Claim 8
Dependent Claim
25 words
The method of claim 1 wherein the alkali metal hydroxides of Step (f) are selected from the group consisting of sodium hydroxide and potassium hydroxide.
Claim 9
Dependent Claim
35 words
The method of claim 1 in which the precipitation of silica of Step (h) is carried out by heating the liquid to a temperature of about 90*C for at least one hour at atmospheric pressure.
Claim 10
Dependent Claim
48 words
The method of claim 1 in which the precipitation of silica of Step (h) is carried out by heating the liquid at a pressure of from about 0.5 atmospheres to about 7 atmospheres at a temperature of from about 90*C to about 200*C for at least fifteen minutes.
Claim 11
Dependent Claim
22 words
The method of claim 1 in which the precipitation of silica of Step (h) is accelerated by seeding with sodium aluminum silicates.
Claim 12
Dependent Claim
28 words
The method of claim 1 in which the precipitation of aluminum hydroxide of Step (j) is carried out by cooling the liquid until crystalline aluminum hydroxide is formed.
Claim 13
Dependent Claim
23 words
The method of claim 1 in which the precipitation of aluminum hydroxide of Step (j) is accelerated by seeding with aluminum hydroxide crystals.
Claim 14
Dependent Claim
20 words
The method of claim 1 containing the additional step of precipitating potassium sulfate from the liquid resulting from Step (e).
Claim 15
Dependent Claim
20 words
The method of claim 1 containing the additional step of converting the sulfate removed in Step (b) into sulfuric acid.
Claim 16
Dependent Claim
20 words
The method of claim 1 containing the additional step of converting the sulfate removed in Step (b) into elemental sulfur.
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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) | 1978-06-16 | 1978-12-16 | 1979-06-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-06-16 | 1982-12-16 | 1983-06-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-06-16 | 1986-12-16 | 1987-06-17 | $7700.00 | Window Closed / Lapsed |