US4333913A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of purifying aqueous solutions of metal hydroxides
Assignee: Olin Corp
•
Filing: 1980-08-18
•
Granted: 1982-06-08
•
Expires: 2000-08-18
Abstract
Abstract A process is disclosed for purifying aqueous solutions of metal hydroxides. An aqueous solution of a metal hydroxide, such as sodium hydroxide, containing a complex of a heavy metal contaminant, such as mercury, is heated. An oxidizing agent, such as hydrogen peroxide, is reacted with the solution to precipitate solid particles of an oxide of the heavy metal, for example, mercuric oxide, in a solution. The solid particles of mercuric oxide are separated from the solution by filtration. The purified solution comprised of water and sodium hydroxide and containing less than about 0.3 part per million mercury by weight is sold commercially. The solid particles of mercuric oxide are landfilled or otherwise utilized.
Inventors
- 👤 Ronald L. Dotson
- 👤 Edward P. Carr
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 12:05
CPC Classifications
C; C22; C22B; C22B43/00; C01; C01D; C01D1/00; C01D1/04; C01D1/28; C01D1/32; C01G; C01G13/00; C01G13/02; C02; C02F; C02F1/00; C02F1/72; C02F1/722; C22B26/00; C22B26/10; C22B3/00; C22B3/20; C22B3/44; C02F2101/00; C02F2101/10; C02F2101/20; C02F2101/30; C02F2101/303; Y; Y02; Y02P; Y02P10/00; Y02P10/20; Y10; Y10S; Y10S210/00; Y10S210/902; Y10S210/911; Y10S210/912; Y10S210/914
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
81 words
A process for purifying an aqueous solution of an alkali metal hydroxide containing a soluble polysulfide complex of mercury and having an alkali metal hydroxide concentration in the range from about 25 to about 75% by weight, which comprises: (a) heating said solution to a temperature of at least 25° C., (b) reacting an inorganic peroxide with said solution to precipitate solid particles of an oxide of said mercury in said solution, and (c) separating said solid particles from said solution.
Claim 2
Dependent Claim
81 words
A process for purifying an aqueous solution of an alkali metal hydroxide containing a soluble polysulfide complex of mercury and having an alkali metal hydroxide concentration in the range from about 25 to about 75% by weight, which comprises: (a) heating said solution to a temperature of at least 25° C., (b) reacting an inorganic peroxide with said solution to precipitate solid particles of an oxide of said mercury in said solution, and (c) separating said solid particles from said solution.
Claim 3
Dependent Claim
13 words
The process of claim 1 wherein said alkali metal hydroxide is sodium hydroxide.
Claim 4
Dependent Claim
12 words
The process of claim 2 wherein said inorganic peroxide is hydrogen peroxide.
Claim 5
Dependent Claim
13 words
The process of claim 1, wherein said alkali metal hydroxide is potassium hydroxide.
Claim 6
Dependent Claim
24 words
The process of claim 1, wherein said solution is heated to a temperature in the range from about 50° C. to about 125° C.
Claim 7
Dependent Claim
21 words
The process of claim 5, wherein said reaction period is in the range of from about 5 to about 15 minutes.
Claim 8
Dependent Claim
29 words
The process of claim 1, wherein said oxidizing agent is reacted with said solution for a reaction period in the range of from about 3 to about 20 minutes.
Claim 9
Dependent Claim
29 words
The process of claim 1 wherein the molar ratio of said inorganic peroxide to said complex of a mercury is in the range from about 8:1 to about 20:1.
Claim 10
Dependent Claim
36 words
The process of claim 8 wherein said soluble polysulfide complex is formed by reacting said mercury with a sulfur containing complexing agent selected from a group consisting of sulfur, sodium sulfide, potassium sulfide, and mixtures thereof.
Claim 11
Dependent Claim
13 words
The process of claim 9 wherein said alkali metal hydroxide is sodium hydroxide.
Claim 12
Dependent Claim
12 words
The process of claim 10 wherein said sulfur-containing complexing agent is sulfur.
Claim 13
Dependent Claim
12 words
The process of claim 11 wherein said inorganic peroxide is hydrogen peroxide.
Claim 14
Dependent Claim
29 words
The process of claim 12 wherein the molar ratio of said inorganic peroxide to said complex of a mercury is in the range from about 10:1 to about 12:1.
Claim 15
Dependent Claim
29 words
The process of claim 1 wherein the molar ratio of said inorganic peroxide to said complex of a mercury is in the range from about 10:1 to about 12:1.
References Cited (Backward Citations)
US3764496A
Cited
US3674428A
Cited
US3764495A
Cited
DE2230367A1
Cited
US4147626A
Cited
US4260494A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1985-06-07 | 1985-12-07 | 1986-06-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-06-07 | 1989-12-07 | 1990-06-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-06-07 | 1993-12-07 | 1994-06-08 | $7700.00 | Window Closed / Lapsed |