Patent US2746840A successfully refreshed from Google Patents.
US2746840A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Purification of concentrated salt solutions
Assignee: Dow Chemical Co
•
Filing: 1952-07-24
•
Granted: 1956-05-22
•
Expires: 1972-07-24
Abstract
No abstract record available.
Inventors
- 👤 Clyde W Davis
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 16:19
CPC Classifications
C; C01; C01F; C01F11/00; C01F11/20; C01F11/24; C01F11/32; C01F5/00; C01F5/26; C01F5/30; C01G; C01G9/00; C01G9/04
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
141 words
THE METHOD WHICH COMPRISES ADDING TO A WATER SOLUTION OF AT LEAST 40 PER CENT SALT CONCENTRATION WHEREIN THE PRINCIPAL SOLUTE IS SELECTED FROM THE GROUP CONSISTING OF ZINC CHLORIDE, CALCIUM CHLORIDE, MAGNESIUM CHLORIDE, AND MIXTURES THEREOF, AND WHICH CONTAINS TRACE AMOUNTS OF THE OXIDE OF THE PRINCIPAL CATION PRESENT AND TRACE AMOUNTS OF AT LEAST IRON AND COPPER SALTS AND IMPURITIES, AN EXCESS OF A WATER-SOLUBLE PERSULFATE OVER THE AMOUNT EQIVALENT TO THE SAID IRON AND OTHER CATIONIC IMPURITIES PRESENT, AT A TEMPERATURE OF AT LEAST 50* C. TO FORM A PRECIPITATE BY REACTION BETWEEN THE PERSULFATE AND SOME OF THE SAID IMPURITIES; FILTERING TO REMOVE THE PRECIPITATE; BOILING THE FILTRATE TO DECOMPOSE REMAINING PERSULFATE; ADDING ZINE DUST TO THE HOT SOLUTION; COOLING THE SOLUTION; AND REMOVING THE REMAINING ZINC DUST TOGETHER WITH THE COPPER WHICH HAS PLATED OUT THEREON.
Claim 2
Independent Claim
141 words
THE METHOD WHICH COMPRISES ADDING TO A WATER SOLUTION OF AT LEAST 40 PER CENT SALT CONCENTRATION WHEREIN THE PRINCIPAL SOLUTE IS SELECTED FROM THE GROUP CONSISTING OF ZINC CHLORIDE, CALCIUM CHLORIDE, MAGNESIUM CHLORIDE, AND MIXTURES THEREOF, AND WHICH CONTAINS TRACE AMOUNTS OF THE OXIDE OF THE PRINCIPAL CATION PRESENT AND TRACE AMOUNTS OF AT LEAST IRON AND COPPER SALTS AND IMPURITIES, AN EXCESS OF A WATER-SOLUBLE PERSULFATE OVER THE AMOUNT EQIVALENT TO THE SAID IRON AND OTHER CATIONIC IMPURITIES PRESENT, AT A TEMPERATURE OF AT LEAST 50* C. TO FORM A PRECIPITATE BY REACTION BETWEEN THE PERSULFATE AND SOME OF THE SAID IMPURITIES; FILTERING TO REMOVE THE PRECIPITATE; BOILING THE FILTRATE TO DECOMPOSE REMAINING PERSULFATE; ADDING ZINE DUST TO THE HOT SOLUTION; COOLING THE SOLUTION; AND REMOVING THE REMAINING ZINC DUST TOGETHER WITH THE COPPER WHICH HAS PLATED OUT THEREON.
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) | 1959-05-22 | 1959-11-21 | 1960-05-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1963-05-22 | 1963-11-21 | 1964-05-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1967-05-22 | 1967-11-21 | 1968-05-22 | $7700.00 | Window Closed / Lapsed |