Process for removal of cationic impurities from technical grade phosphoric acid
Abstract
Abstract Technical grade phosphoric acid is purified of cationic impurities by adding thereto alkali or ammonium ions and a water soluble organic solvent whereby a flaky, easily filterable precipitate is formed which is subsequently separated from the filtrate. The filtrate is passed through a highly acidic cationic exchange resin in the H+ form. The organic solvent is distilled from the filtrate to produce purified phosphoric acid. The source of alkali ions include gaseous ammonia, alkali and ammonium hydroxide and/or alkali and ammonium salts with the addition being of from 0.06 to 0.12 mols of alkali ions per mol of P2O5. The water soluble organic solvent is preferably isopropanol and is added in an amount of from two to five times the amount with respect to the raw phosphoric acid.
Inventors
- 👤 K Frankenfeld
- 👤 K Gotzmann
Bibliographic Details
Claims Analysis
Total Claims: 5References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-10-08 | 1977-04-09 | 1977-10-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-10-08 | 1981-04-09 | 1981-10-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-10-08 | 1985-04-09 | 1985-10-09 | $7700.00 | Window Closed / Lapsed |