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US4072605A
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Method of obtaining a precipitate of metallic ions from solutions containing low concentrations of metal salts
Assignee: Automated Medical Systems Inc
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Filing: 1976-05-25
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Granted: 1978-02-07
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Expires: 1996-05-25
Abstract
Abstract A method and process for removal by precipitation of salts of a variety of metallic elements from aqueous solutions, including for example, copper, cadmium, chromium, zinc, nickel, lead, tin, platinum, rhodium and others with each of the metallic elements having multiple valent states. The process includes the establishment of a simultaneous oxidative-reductive cycle within the aqueous solutions, with the oxidative-reductive cycle normally being generated through the use of iodine, normally in the form of the iodide or iodate and phosphorous acid. In certain reactions, it is desirable that the pH be controlled and in such solutions, the phosphorous acid may be added in the form of a sodium salt of phosphorous acid. In the utilization of the multivalent materials, the least soluble salt generated during the oxidative-reductive cycle is removed.
Inventors
- 👤 Paul F. Thelander
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 17:49
CPC Classifications
C; C02; C02F; C02F9/00; C02F1/00; C02F1/52; C02F1/5236; C02F1/58; C02F1/62; C02F1/72; C02F1/76; C02F1/766; C02F2101/00; C02F2101/10; C02F2101/20; C02F2101/22; C02F2209/00; C02F2209/06; Y; Y10; Y10S; Y10S210/00; Y10S210/902; Y10S210/911; Y10S210/912; Y10S210/914
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
106 words
The method of precipitating salts of metallic elements having multiple valent states and selected from the group consisting of copper, chromium, zinc, cadmium, nickel, lead, platinum, antimony, iron, manganese, aluminum, thorium, tin, mercury, vanadium, rhodium and silver from aqueous solutions of said metallic elements, said method comprising: a. introducing phosphorous acid and an excess of a halogen selected from the group consisting of iodine, iodide and iodate to said aqueous solution to form a simultaneous oxidative-reductive cycle within said aqueous solution involving said metallic element; and b. precipitating and removing the salt of the less soluble valence state of said metallic element from said aqueous solution.
Claim 2
Independent Claim
106 words
The method of precipitating salts of metallic elements having multiple valent states and selected from the group consisting of copper, chromium, zinc, cadmium, nickel, lead, platinum, antimony, iron, manganese, aluminum, thorium, tin, mercury, vanadium, rhodium and silver from aqueous solutions of said metallic elements, said method comprising: a. introducing phosphorous acid and an excess of a halogen selected from the group consisting of iodine, iodide and iodate to said aqueous solution to form a simultaneous oxidative-reductive cycle within said aqueous solution involving said metallic element; and b. precipitating and removing the salt of the less soluble valence state of said metallic element from said aqueous solution.
Claim 3
Dependent Claim
23 words
The method as defined in claim 1 being particularly characterized in that said halogen is added to said solution as the iodide ion.
Claim 4
Dependent Claim
63 words
The method as defined in claim 1 being particularly characterized in that an alkali hydroxide is added to activate the reaction through controlling the reduction of free iodine and activates the free electrons of the phosphorous atom of said phosphorous acid in the conjugated base form by means of the proposed intermediate hydride ion which in turn, releases these electrons for reduction purposes.
Claim 5
Dependent Claim
33 words
The method as defined in claim 1 being particularly characterized in that said phosphorous acid is present as a phosphorous salt selected from the group consisting of hydrogen phosphite and sodium bi-hydrogen phosphite.
Claim 6
Dependent Claim
34 words
The method as defined in claim 1 being particularly characterized in that said halogen is present in said solution as a salt selected from the group consisting of soluble iodides, soluble iodates, or iodine.
Claim 7
Dependent Claim
34 words
The method as defined in claim 1 being particularly characterized in that the pH of said aqueous solution following introduction of said halogen and phosphorous acid is generally on the acid side of neutrality.
Claim 8
Dependent Claim
36 words
The method as defined in claim 1 being particularly characterized in that an alkaline earth oxide is added to enhance oxidative-reductive functions to form corresponding oxides of the metallic ions following the path of oxide formation.
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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) | 1981-02-06 | 1981-08-08 | 1982-02-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-02-06 | 1985-08-08 | 1986-02-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-02-06 | 1989-08-08 | 1990-02-07 | $7700.00 | Window Closed / Lapsed |