US4147626A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Treatment of mercury contaminated aqueous media
Assignee: Domtar Inc
•
Filing: 1977-01-07
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Granted: 1979-04-03
•
Expires: 1997-01-07
Abstract
Abstract A technique for removing substantially all the elemental mercury from a mercury containing aqueous media by adjusting the pH of the liquid to the range of 7-13, adding a polysulfide in an amount sufficient to combine with the elemental mercury to form a mercury sulfide which is precipitated and preventing the mercury from being resolublized.
Inventors
- 👤 David M. Findlay
- 👤 Ronald A. N. McLean
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 08:53
CPC Classifications
C; C02; C02F; C02F1/00; C02F1/52; C02F1/5236; C01; C01G; C01G13/00; Y; Y10; Y10S; Y10S210/00; Y10S210/902; Y10S210/911; Y10S210/912; Y10S210/914
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
78 words
A process for the treatment of aqueous effluent from a chlor-alkali plant containing elemental mercury and other undissolved solids to convert substantially all said elemental mercury to a stable form that does not contaminate the environment consisting essentially of: adding a water-soluble polysulfide to said solids containing effluent at a pH in the range 7-13 in an amount sufficient to combine with substantially all said elemental mercury to form insoluble mercury sulfide and separating solids from said effluent.
Claim 2
Dependent Claim
78 words
A process for the treatment of aqueous effluent from a chlor-alkali plant containing elemental mercury and other undissolved solids to convert substantially all said elemental mercury to a stable form that does not contaminate the environment consisting essentially of: adding a water-soluble polysulfide to said solids containing effluent at a pH in the range 7-13 in an amount sufficient to combine with substantially all said elemental mercury to form insoluble mercury sulfide and separating solids from said effluent.
Claim 3
Dependent Claim
14 words
A method as defined in claim 1 wherein said polysulfide is a sodium polysulfide.
Claim 4
Dependent Claim
50 words
A method is defined in claim 1 wherein said effluent also includes ionic mercury and wherein a soluble sulfide is also added to said effluent, said polysulfide and said sulfide being present in the amount to combine with substantially all of said elemental mercury and ionic mercury in said effluent.
Claim 5
Dependent Claim
19 words
A method is defined in claim 3 wherein said sulfide and said polysulfide are sodium polysulfide and sodium sulfide.
Claim 6
Dependent Claim
18 words
A method is defined in claim 3 wherein said pH is in the range of 9 to 12.
Claim 7
Dependent Claim
28 words
A method as defined in claim 3 further comprising separating the mercury sulfide from said effluent before a significant portion of said mercury sulfide has time to resolublize.
Claim 8
Dependent Claim
23 words
A method as defined in claim 6 wherein said mercury sulfide is separated from said effluent immediately after said mercury sulfide is formed.
References Cited (Backward Citations)
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Cited
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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) | 1982-04-02 | 1982-10-02 | 1983-04-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-04-02 | 1986-10-02 | 1987-04-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-04-02 | 1990-10-02 | 1991-04-03 | $7700.00 | Window Closed / Lapsed |