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US2885263A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Anhydrite process for phosphoric acid manufacture
Assignee: Chemical Construction Corp
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Filing: 1955-06-10
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Granted: 1959-05-05
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Expires: 1975-06-10
Abstract
No abstract record available.
Inventors
- 👤 Robert B Peet
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 18:07
CPC Classifications
C; C01; C01B; C01B25/00; C01B25/16; C01B25/18; C01B25/22; C01B25/222; C01B25/228; C01B25/2285
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
146 words
A METHOD FOR THE PRODUCTION OF STRONG PHOSPHORIC ACID OF AT LEAST 40% P205 CONTENT WHICH COMPRISES DIGESTING PHOSPHATE ROCK IN STRONG AQUEOUS PHOSPHORIC ACID, REACTING THE RESULTING MONOCALCIUM PHOSPHATE SOLUTION WITH SULFURIC ACID THEREBY FORMING A SUSPENSION OF CALCIUM SULFATE HEMIHYDRATE CRYSTALS IN AQUEOUS PHOSPHORIC ACID OF AT LEAST 40% P205 CONTENT SAID SULFURIC ACID BEING ADDED IN AMOUNTS WHICH ARE ABOUT 1-4% IN EXCESS OF THAT NECESSARY TO REACT WITH MONOCALCIUM PHOSPHATE SAID SUSPENSION, ADDING SEED CRYSTAL OF CALCIUM SULFATE ANHYDRITE TO SAID SUSPENSION, HEATING THIS SUSPENSION AT TEMPERATURES OF AT LEAST 100* C. FOR ABOUT 1-4 HOURS TO CONVENT A MAJOR PROPORTION OF SAID CALCIUM SULFATE HEMIHYDRATE CRYSTALS INTO CRYSTALS OF CALCIUM SULFATE ANHYDRITE, AND FILTERING THE SLURY SO OBTAINED TO PRODUCE A FILTER CAKE OF CALCIUM SULFATE ANHYDRITE CRYSTALS AND A FILTRATE OF STRONG PHOSPHORIC ACID OF AT LEAST 40% P205 CONCENTRATION.
Claim 2
Independent Claim
146 words
A METHOD FOR THE PRODUCTION OF STRONG PHOSPHORIC ACID OF AT LEAST 40% P205 CONTENT WHICH COMPRISES DIGESTING PHOSPHATE ROCK IN STRONG AQUEOUS PHOSPHORIC ACID, REACTING THE RESULTING MONOCALCIUM PHOSPHATE SOLUTION WITH SULFURIC ACID THEREBY FORMING A SUSPENSION OF CALCIUM SULFATE HEMIHYDRATE CRYSTALS IN AQUEOUS PHOSPHORIC ACID OF AT LEAST 40% P205 CONTENT SAID SULFURIC ACID BEING ADDED IN AMOUNTS WHICH ARE ABOUT 1-4% IN EXCESS OF THAT NECESSARY TO REACT WITH MONOCALCIUM PHOSPHATE SAID SUSPENSION, ADDING SEED CRYSTAL OF CALCIUM SULFATE ANHYDRITE TO SAID SUSPENSION, HEATING THIS SUSPENSION AT TEMPERATURES OF AT LEAST 100* C. FOR ABOUT 1-4 HOURS TO CONVENT A MAJOR PROPORTION OF SAID CALCIUM SULFATE HEMIHYDRATE CRYSTALS INTO CRYSTALS OF CALCIUM SULFATE ANHYDRITE, AND FILTERING THE SLURY SO OBTAINED TO PRODUCE A FILTER CAKE OF CALCIUM SULFATE ANHYDRITE CRYSTALS AND A FILTRATE OF STRONG PHOSPHORIC ACID OF AT LEAST 40% P205 CONCENTRATION.
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) | 1962-05-04 | 1962-11-03 | 1963-05-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1966-05-04 | 1966-11-03 | 1967-05-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1970-05-04 | 1970-11-03 | 1971-05-05 | $7700.00 | Window Closed / Lapsed |