US3857704A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Mercury recovery process
Assignee: BP Chemicals Ltd
•
Filing: 1972-03-03
•
Granted: 1974-12-31
•
Expires: 1992-03-03
Abstract
Abstract A process for the recovery of mercury from aqueous solutions containing elemental mercury in finely divided or colloidal form or in the form of a soluble inorganic compound by treating the solution with a chemical reducing agent such as ferrous sulphate at a pH greater than 5, iron or steel turnings or chips, hydrazine, hydroxylamine, D-glucose and sodium borohydride with simultaneous removal of the resulting finely divided or colloidal mercury from the solution as a vapour and recovering the mercury from vapour. Methods of removing mercury as a vapour are by passing a stream of inert gas through the solution and steam distillation, which latter term includes injection of ''''live'''' steam and using the technique of single or multiple stage flash distillation under vacuum. A combination of the two methods is found most effective.
Inventors
- 👤 M Coulter
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 19:34
CPC Classifications
C; C02; C02F; C02F9/00; C01; C01G; C01G13/00; C02F1/00; C02F1/02; C02F1/04; C02F1/048; C02F1/06; C02F1/70; C22; C22B; C22B43/00; C02F1/705; C02F2101/00; C02F2101/10; C02F2101/20; Y; Y10; Y10S; Y10S210/00; Y10S210/902; Y10S210/911; Y10S210/912; Y10S210/914
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
95 words
A PROCESS FOR THE REMOVAL AND RECOVERY OF MERCURY FROM AQUEOUS SOLUTIONS CONTAINING SOLUBLE INORGANIC COMPOUND OF MERCURY AND HAVING A MERCURY CONCENTRATION NOT MORE THAN 100 MULLIGRAMS PER LITER WHICH COMPRISES TREATING SAID AQUEOUS SOLUTION WITH A CHEMICAL REDUCING AGENT SELECTED FROM THE GROUP CONSISTING OF FERROUS SULPHATE AT A PH GREATER THAN 5, HYDRAZINE, IRON OR STEEL TURNINGS OR CHIPS, HYDROXYLAMINE, DGLUSOSE AND SODIUM BOROHYDRIDE PRECIPITATE FINELY DIVIDED ELEMENTAL MERCURY, REMOVING SAID MERCURY BY APPLYING A VACUUM AND USING SINGLE STAGE OR MULTIPLE STAGE FLASH DISTILLATION, AND RECOVERING SAID MERCURY FROM THE VAPOR.
Claim 2
Dependent Claim
95 words
A PROCESS FOR THE REMOVAL AND RECOVERY OF MERCURY FROM AQUEOUS SOLUTIONS CONTAINING SOLUBLE INORGANIC COMPOUND OF MERCURY AND HAVING A MERCURY CONCENTRATION NOT MORE THAN 100 MULLIGRAMS PER LITER WHICH COMPRISES TREATING SAID AQUEOUS SOLUTION WITH A CHEMICAL REDUCING AGENT SELECTED FROM THE GROUP CONSISTING OF FERROUS SULPHATE AT A PH GREATER THAN 5, HYDRAZINE, IRON OR STEEL TURNINGS OR CHIPS, HYDROXYLAMINE, DGLUSOSE AND SODIUM BOROHYDRIDE PRECIPITATE FINELY DIVIDED ELEMENTAL MERCURY, REMOVING SAID MERCURY BY APPLYING A VACUUM AND USING SINGLE STAGE OR MULTIPLE STAGE FLASH DISTILLATION, AND RECOVERING SAID MERCURY FROM THE VAPOR.
Claim 3
Dependent Claim
37 words
A process as defined in claim 1 wherein said elemental mercury is removed by passing a stream of inert gas through the mercury containing aqueous solution, applying a vacuum and using multiple or single stage flash distillation.
Claim 4
Dependent Claim
39 words
A process as defined in claim 1 wherein at least a portion of said soluble inorganic compound of mercury is formed by treating elemental mercury, organic compounds of mercury, or water-insoluble inorganic compounds of mercury with an oxidizing agent.
Claim 5
Dependent Claim
16 words
A process as defined in claim 3 wherein said oxidizing agnet is chlorine or nitric acid.
Claim 6
Dependent Claim
29 words
A process as defined in claim 1 wherein said reducing agent is sodium borohydride and the treatment with said reducing agent is carried out at a pH of 11.
Claim 7
Dependent Claim
29 words
A process as defined in claim 1 wherein any oxidizing agents, other than mercury compounds, present in the aqueous solution are first reduced with sodium sulphite or sulphur dioxide.
Claim 8
Dependent Claim
28 words
A process as defined in claim 1 wherein in the step of recovering said mercury from the vapor the vapor is condensed by contact with a cooled surface.
Claim 9
Dependent Claim
33 words
A process as defined in claim 7 wherein said mercury is separated from the condensate by passage through a bed composed of fibers of small diameter and then a gravity separator or centrifuge.
Claim 10
Dependent Claim
22 words
A process as defined in claim 1 wherein said aqueous solution being treated is depleted brine from a mercury cell chlorine process.
References Cited (Backward Citations)
US3039865A
Cited
US3324009A
Cited
US3320137A
Cited
US3537843A
Cited
US3695838A
Cited
US3679396A
Cited
US3734835A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-12-30 | 1978-07-01 | 1978-12-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-12-30 | 1982-07-01 | 1982-12-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-12-30 | 1986-07-01 | 1986-12-31 | $7700.00 | Window Closed / Lapsed |