US3932591A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for the manufacture of phosphoric acid with minimized environmental effects
Assignee: United States Steel Corp
•
Filing: 1972-04-19
•
Granted: 1976-01-13
•
Expires: 1992-04-19
Abstract
Abstract An improved process for preparing wet process phosphoric acid by calcining a phosphate source at a temperature in the range of 1600 DEG - 2200 DEG F. The phosphate source may be wet or dry mined phosphate matrix, phosphate slimes, phosphate pebble or other phosphate source.
Inventors
- 👤 Rogelio Serge Ribas
- 👤 John D. Nickerson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 06:57
CPC Classifications
C; C01; C01B; C01B25/00; C01B25/16; C01B25/18; C01B25/22
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
103 words
In a process for producing phosphoric acid wherein phosphate rock is mined, beneficiated, the beneficiated product separated into a slimes stream, one or more pebble streams, and a concentrate stream, the slimes stream discarded, and the pebble streams digested with mineral acid and filtered to remove impurities, the improvement comprising dewatering the slimes stream to a sollds content of at least 40 percent by weight, calcining the dewatered slimes at a temperature in the range of 1600° to 2200°F, combining the calcined slimes with the beneficiated pebble prior to digesting with a mineral acid and filtering the resultant slurry to remove solid matter.
Claim 2
Dependent Claim
103 words
In a process for producing phosphoric acid wherein phosphate rock is mined, beneficiated, the beneficiated product separated into a slimes stream, one or more pebble streams, and a concentrate stream, the slimes stream discarded, and the pebble streams digested with mineral acid and filtered to remove impurities, the improvement comprising dewatering the slimes stream to a sollds content of at least 40 percent by weight, calcining the dewatered slimes at a temperature in the range of 1600° to 2200°F, combining the calcined slimes with the beneficiated pebble prior to digesting with a mineral acid and filtering the resultant slurry to remove solid matter.
Claim 3
Dependent Claim
31 words
The process of claim 1 wherein the dewatered slimes have a solids content of about 50 percent by weight and the calcination temperature is in the range of 1750° to 2000°F.
Claim 4
Dependent Claim
32 words
The process of claim 1 wherein the dewatered slimes are added to the beneficiated pebble prior to calcination and the mixture calcined at a temperature in the range of 1600° to 2200°F.
Claim 5
Dependent Claim
17 words
The process of claim 3 wherein the calcination temperature is in the range of 1750° to 2000°F.
Claim 6
Dependent Claim
58 words
A process for the preparation of phosphoric acid from phosphate slimes comprising dewatering the slimes to a minimum solids content of 40 percent by weight, calcining the dewatered slimes at a temperature in the range of 1600° to 2200°F digesting the calcined slimes in a mineral acid, and filtering to remove solid matter from the product phosphoric acid.
Claim 7
Dependent Claim
58 words
A process for the preparation of phosphoric acid from phosphate slimes comprising dewatering the slimes to a minimum solids content of 40 percent by weight, calcining the dewatered slimes at a temperature in the range of 1600° to 2200°F digesting the calcined slimes in a mineral acid, and filtering to remove solid matter from the product phosphoric acid.
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) | 1979-01-12 | 1979-07-14 | 1980-01-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-01-12 | 1983-07-14 | 1984-01-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-01-12 | 1987-07-14 | 1988-01-13 | $7700.00 | Window Closed / Lapsed |