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US4572797A
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Method for removing trace pollutants from aqueous solutions
Assignee: United States, AS REPRESENTED BY DOE
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Filing: 1983-03-02
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Granted: 1986-02-25
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Expires: 2003-03-02
Abstract
Abstract A method of substantially removing a trace metallic contaminant from a liquid containing the same comprises, adding an oxidizing agent to a liquid containing a trace amount of a metallic contaminant of a concentration of up to about 10-1 ppm, the oxidizing agent being one which oxidizes the contaminant to form an oxidized product which is insoluble in the liquid and precipitates therefrom, and the conditions of the addition being selected to ensure that the precipitation of the oxidized product is homogeneous, and separating the homogeneously precipitated product from the liquid.
Inventors
- 👤 Gary L. Silver
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 20:00
CPC Classifications
C; C02; C02F; C02F1/00; C02F1/72; G; G21; G21F; G21F9/00; G21F9/04; G21F9/06; C02F2101/00; C02F2101/10; C02F2101/20
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
137 words
A method of substantially removing a trace metallic contaminant from a liquid containing the same, consisting of: continuously adding an oxidizing agent to a liquid containing up to 10 -2 ppm of the contaminant to form an oxidized product which precipitates therefrom, with the conditions of the addition being selected to ensure that the precipitation of the oxidized product is homogeneous; and continuously separating the homogeneous precipitated product from the liquid by allowing said precipitate to crystallize on the walls of a cylindrical container in which the method is carried out; said contaminant being cobalt, nickel, manganese, thallium, iron (II), platinum, iridium, antimony, strontium, osmium, lead, tin, uranium, or plutonium; and said oxidizing agent being an alkali or alkaline earth metal hypochlorite or a combination of an alkali or alkaline earth metal sulfite and O 2 .
Claim 2
Independent Claim
137 words
A method of substantially removing a trace metallic contaminant from a liquid containing the same, consisting of: continuously adding an oxidizing agent to a liquid containing up to 10 -2 ppm of the contaminant to form an oxidized product which precipitates therefrom, with the conditions of the addition being selected to ensure that the precipitation of the oxidized product is homogeneous; and continuously separating the homogeneous precipitated product from the liquid by allowing said precipitate to crystallize on the walls of a cylindrical container in which the method is carried out; said contaminant being cobalt, nickel, manganese, thallium, iron (II), platinum, iridium, antimony, strontium, osmium, lead, tin, uranium, or plutonium; and said oxidizing agent being an alkali or alkaline earth metal hypochlorite or a combination of an alkali or alkaline earth metal sulfite and O 2 .
Claim 3
Dependent Claim
12 words
The method of claim 1 wherein the contaminant is a radioactive metal.
Claim 4
Dependent Claim
11 words
The method of claim 2 wherein the contaminant is radioactive cobalt.
Claim 5
Dependent Claim
30 words
The method of claim 1 wherein the oxidixing agent is a combination of calcium sulfite or sodium sulfite and O 2 and the pH of the liquid is about 5-13.
Claim 6
Dependent Claim
25 words
The method of claim 4 wherein the oxidizing agent is a combination of calcium sulfite, a liquid-soluble soluble Ni 2+ salt and O 2 .
Claim 7
Dependent Claim
21 words
The method of claim 4 wherein the oxidizing agent is sodium hypochlorite and the pH of the liquid is about 3-13.
Claim 8
Dependent Claim
32 words
The method of claim 1 wherein the contaminant is radioactive cobalt and wherein non-radioactive cobalt is added prior to oxidation and precipitation to raise the total cobalt concentration to about 1000 ppm.
References Cited (Backward Citations)
US3203786A
Cited
US4006216A
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US4086325A
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US4338200A
Cited
US4312758A
Cited
US4377508A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-02-24 | 1989-08-26 | 1990-02-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-02-24 | 1993-08-26 | 1994-02-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-02-24 | 1997-08-26 | 1998-02-25 | $7700.00 | Window Closed / Lapsed |