US2632688A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Production of chromium trioxide
Assignee: Diamond Shamrock Corp
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Filing: 1952-02-15
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Granted: 1953-03-24
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Expires: 1972-02-15
Abstract
No abstract record available.
Inventors
- 👤 Tom S Perrin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 21:57
CPC Classifications
C; C01; C01G; C01G37/00; C01G37/02; C01G37/033; C01P; C01P2006/00; C01P2006/80
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
132 words
IN THE RECOVERY OF CHROMIC ANHYDRIDE FROM A CONCENTRATED AQUEOUS SOLUTION OF AN ALKALI METAL DICHROMATE BY ADDING CONCENTRATED SULFURIC ACID TO SAID SOLUTION TO PRECIPITATE CHROMIC ANHYDRIDE, SEPARATING THE PRECIPITATE OF CHROMIC ANHYDRIDE WITH ADHERING MOTHER LIQUOR AS A MASS OF CRUDE CHROMIC ANHYDRIDE CRYSTALS, AND RECOVERING SUBSTANTIALLY PURE CHROMIC ANHYDRIDE FROM SAID MASS OF CRUDE CRYSTALS, THE IMPROVEMENT WHICH INCLUDES WASHING SAID MASS OF CRUDE CRYSTALS WITH A SATURATED AQUEOUS SOLTUION OF SAID ALKALI METAL DICHROMATE, HEATING SAID WASHED CRYSTAL MASS TO THE FUSION POINT THEREOF, ALLOWING THE FUSED MASS TO STRATIFY IN THE MOLTEN CONDITION TO FORM A LOWER LAYER OF SUBSTANTIALLY PURE CHROMIC ANHYDRIDE AND AN UPPER LAYER OF DROSS, SEPARATING SAID SUBSTANTIALLY PURE CHROMIC ANHYDRIDE FROM SAID DROSS, AND SEPARATELY RECOVERING SAID CHROMIC ANHYDRIDE AND SAID DROSS.
Claim 2
Dependent Claim
132 words
IN THE RECOVERY OF CHROMIC ANHYDRIDE FROM A CONCENTRATED AQUEOUS SOLUTION OF AN ALKALI METAL DICHROMATE BY ADDING CONCENTRATED SULFURIC ACID TO SAID SOLUTION TO PRECIPITATE CHROMIC ANHYDRIDE, SEPARATING THE PRECIPITATE OF CHROMIC ANHYDRIDE WITH ADHERING MOTHER LIQUOR AS A MASS OF CRUDE CHROMIC ANHYDRIDE CRYSTALS, AND RECOVERING SUBSTANTIALLY PURE CHROMIC ANHYDRIDE FROM SAID MASS OF CRUDE CRYSTALS, THE IMPROVEMENT WHICH INCLUDES WASHING SAID MASS OF CRUDE CRYSTALS WITH A SATURATED AQUEOUS SOLTUION OF SAID ALKALI METAL DICHROMATE, HEATING SAID WASHED CRYSTAL MASS TO THE FUSION POINT THEREOF, ALLOWING THE FUSED MASS TO STRATIFY IN THE MOLTEN CONDITION TO FORM A LOWER LAYER OF SUBSTANTIALLY PURE CHROMIC ANHYDRIDE AND AN UPPER LAYER OF DROSS, SEPARATING SAID SUBSTANTIALLY PURE CHROMIC ANHYDRIDE FROM SAID DROSS, AND SEPARATELY RECOVERING SAID CHROMIC ANHYDRIDE AND SAID DROSS.
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) | 1956-03-23 | 1956-09-22 | 1957-03-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1960-03-23 | 1960-09-22 | 1961-03-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1964-03-23 | 1964-09-22 | 1965-03-24 | $7700.00 | Window Closed / Lapsed |