Phosphoric acid manufacture from gypsum and phosphate rock
Abstract
Abstract PHOSPHATE ROCK IS DIGESTED WITH SULFURIC ACID TO PRODUCE PHOSPHORIC ACID AND CALCIUM SULFATE. AN ALKALI METAL SULFATE, SUCH AS POTASSIUM OR SODIUM SULFATE, IS REACTED WITH FLUOSILICIC ACID TO PRODUCE SULFURIC ACID AND THE POTASSIUM OR SODIUM SILICOFLUORIDE, THE SULFURIC ACID BEING RECYCLED TO THE DIGESTION STEP. THE SILICOFLUORIDE IS CALCINED WITH SILICON OXIDE TO PRODUCE THE POTASSIUM OR SODIUM SILICATE AND SILICON TETRAFLUORIDE. THE CALCIUM SULFATE FROM THE DIGESTION STEP TOGETHER WITH THE POTASSIUM OR SODIUM SILICATE ARE CALCINED TO PRODUCE THE POTASSIUM OR SODIUM SULFATE AND CALCIUM SILICATE. WATER IS ADDED TO THE SILICON TETRAFLUORIDE TO PRODUCE FLUOSILICIC ACID, AND THE POTASSIUM OR SODIUM SULFATE AND THE FLUOSILICIC ACID ARE RECYCLED TO THE REACTION STEP DESCRIBED ABOVE FOR PRODUCING THE SULFURIC ACID.
Inventors
- 👤 William A Satterwhite
- 👤 Fred J Klem
Bibliographic Details
Claims Analysis
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| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1974-03-01 | 1974-08-31 | 1975-03-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-03-01 | 1978-08-31 | 1979-03-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-03-01 | 1982-08-31 | 1983-03-02 | $7700.00 | Window Closed / Lapsed |