Patent US3770423A successfully refreshed from Google Patents.
US3770423A
Expired / Lapsed
US
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Process for removing dissolved lead compounds from aqueous media
Assignee: EIDP Inc
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Filing: 1972-02-04
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Granted: 1973-11-06
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Expires: 1992-02-04
Abstract
Abstract Process for treating an aqueous medium containing dissolved organic and inorganic lead compounds, for example, aqueous effluent from the manufacture of tetraalkyl lead, with an alkali metal borohydride to substantially reduce the level of dissolved lead in the aqueous medium.
Inventors
- 👤 C Lores
- 👤 R Moore
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 09:56
CPC Classifications
C; C22; C22B; C22B13/00; C22B13/04; Y; Y10; Y10S; Y10S210/00; Y10S210/902; Y10S210/911; Y10S210/912
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
13 words
The process of claim 1 wherein the alkali metal borohydride is sodium borohydride.
Claim 2
Dependent Claim
13 words
The process of claim 1 wherein 30-50 percent alkali metal borohydride is employed.
Claim 3
Dependent Claim
15 words
The process of claim 1 wherein the pH of the effluent is adjusted to 8.5-10.
Claim 4
Dependent Claim
26 words
The process of claim 1 wherein a flocculating agent is employed along with the borohydride in an amount, by weight, 0.3-0.5 times the amount of borohydride.
Claim 5
Dependent Claim
53 words
The process of claim 1 wherein the aqueous medium is effluent from the manufacture of tetraalkyllead compounds, the effluent and borohydride are contacted in a continuous process wherein the pH is maintained at 8.5-10 and the treated effluent is continuously moved away from and decanted from the insoluble lead-containing product which settles out.
Claim 6
Dependent Claim
26 words
The process of claim 6 wherein a flocculating agent is employed along with the borohydride in an amount, by weight, 0.3-0.5 times the amount of borohydride.
Claim 7
Dependent Claim
19 words
The process of claim 1 wherein the treated aqueous medium is separated from the insoluble lead-containing product by decantation.
Claim 8
Dependent Claim
19 words
The process of claim 1 wherein the insoluble lead-containing product is separated from the treated aqueous medium by filtration.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-11-05 | 1977-05-07 | 1977-11-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-11-05 | 1981-05-07 | 1981-11-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-11-05 | 1985-05-07 | 1985-11-06 | $7700.00 | Window Closed / Lapsed |