US3954580A
Expired / Lapsed
US
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Processes for decreasing mercury butter formation in mercury electrolytic cells
Assignee: Dow Chemical Co
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Filing: 1973-09-10
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Granted: 1976-05-04
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Expires: 1993-09-10
Abstract
Abstract Processes for decreasing mercury butter formation in mercury electrolytic cells employing brine which contains strontium wherein the brine is treated to lower the strontium content to 0.5 ppm or less. The removal of strontium from the brine may be effected by treating the brine with an ion exchange resin in sodium form to adsorb strontium thereon. Alternatively, strontium may be removed by treating the brine with a water-soluble metal hydroxide, subjecting the resulting mixture to partial evaporation to produce sodium chloride as precipitate and saturated brine solution and admixing the precipitate with water to form brine for electrolysis.
Inventors
- 👤 Chester J. Kaminski
- 👤 Bruce T. Smith
- 👤 Alfred R. Taylor
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 23:44
CPC Classifications
C; C25; C25B; C25B1/00; C25B1/01; C25B1/34; C25B1/36
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
55 words
A process for decreasing the rate of mercury butter formation in a mercury electrolytic cell during electrolysis in the cell of a sodium chloride brine containing strontium in a concentration greater than 0.5 ppm, which comprises treating said brine prior to the electrolysis thereof, thereby lowering the strontium content thereof to 0.5 ppm or below.
Claim 2
Dependent Claim
55 words
A process for decreasing the rate of mercury butter formation in a mercury electrolytic cell during electrolysis in the cell of a sodium chloride brine containing strontium in a concentration greater than 0.5 ppm, which comprises treating said brine prior to the electrolysis thereof, thereby lowering the strontium content thereof to 0.5 ppm or below.
Claim 3
Dependent Claim
64 words
The process according to claim 1 wherein said brine is treated by admixing with said brine a water-soluble metal hydroxide, partially evaporating the resulting mixture to produce sodium chloride as precipitate and saturated brine solution as mother liquor, separating said sodium chloride precipitate and admixing said precipitate with water to form a treated brine containing strontium in a concentration of 0.5, ppm or less.
Claim 4
Dependent Claim
26 words
The process according to claim 2 wherein said water-soluble metal hydroxide is admixed with the brine in an amount of between about 0.2 and 130 g/l.
Claim 5
Dependent Claim
24 words
The process according to claim 2 wherein from about 30-80 weight percent of the water content of said brine/water-soluble metal hydroxide mixture is evaporated.
Claim 6
Dependent Claim
35 words
The process according to claim 1 wherein said brine is treated by contacting said brine with an ion exchange resin in sodium form to absorb strontium thereon, said ion exchange resin containing iminodiacetate active groups.
Claim 7
Dependent Claim
22 words
The process according to claim 1 wherein said ion exchange resin contains iminodiacetate active groups attached to a styrene-divinyl benzene copolymer matrix.
Claim 8
Dependent Claim
18 words
The process according to claim 1 wherein said mother liquor is recycled to a subsequent partial evaporation step.
Claim 9
Dependent Claim
16 words
The process according to claim 1 wherein said water-soluble metal hydroxide is an alkali metal hydroxide.
Claim 10
Dependent Claim
14 words
The process according to claim 1 wherein said alkali metal hydroxide is sodium hydroxide.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-05-04 | 1979-11-03 | 1980-05-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-05-04 | 1983-11-03 | 1984-05-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-05-04 | 1987-11-03 | 1988-05-04 | $7700.00 | Window Closed / Lapsed |