Process for producing phosphoric acid
Abstract
Abstract A PROCESS FOR THE PRODUCTION OF PHOSPHORIC ACID FROM PHOSPHATE ROCK COMPRISING REACTING THE PHOSPHATE ROCK WITH AN EQUILIBRATED PHOSPHORIC ACID HAVING A P2O5 CONCENTRATION BETWEEN ABOUT 20 TO 50% IN AN ATTACK STAGE AT A TEMPERATURE BELOW ABOUT 180*F. TO DISSOLVE AT LEAST ABOUT 90% OF THE PHOSPHATE VALUES IN THE ROCK AND PRODEUCE A MONOCALCIUM PHOSPHATE-PHOSPHORIC ACID-WATER SOLUTION UP TP ABOUT 90% SATURATED WITH MONOCALCIUM PHOSPHATE, REACTING SULFURIC ACID WITH SAID SOLUTION TO PRODUCE PHOSPHORIC ACID AND PRECIPITATE CALCIUM SULFATE, THE SULFURIC ACID BEING ADDED IN AN AMOUNT ESSENTIALLY STOICHIOMETRIC WITH RESPECT TO THE MONOCALCIUM PHOSPHATE IN THE SOLUTION, SEPARATING THE CALCIUM SULFATE FROM THE PHOSPHORIC ACID SOLUTION, REMOVING A PORTION OF THE PHOSPHORIC ACID AS A PRODUCT, AND RECYCLING THE REMAINING PHOSPHORIC ACID SOLUTION TO THE ATTACK STAGE TO PROVIDE SAID EQUILIBRATED ACID.
Inventors
- 👤 E Case
Bibliographic Details
Claims Analysis
Total Claims: 0References 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) | 1977-02-11 | 1977-08-13 | 1978-02-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-02-11 | 1981-08-13 | 1982-02-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-02-11 | 1985-08-13 | 1986-02-12 | $7700.00 | Window Closed / Lapsed |