US3635669A
Expired / Lapsed
US
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Method of producing concentrated phosphoric acid compounds from phosphate rock
Assignee: B D Bohna & Co Inc
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Filing: 1968-12-26
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Granted: 1972-01-18
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Expires: 1988-12-26
Abstract
Abstract Phosphate rock is digested with molten ammonium bisulfate and between 5 and 16 percent by weight of water to form a solid reaction product. The water is added to the mixture of phosphate rock and ammonium bisulfate either before, during or after the digestion reaction between the phosphate rock and molten ammonium bisulfate. Concentrated phosphoric acid is extracted from the ground, solid reaction product with a nonaqueous, polar, oxygencontaining organic solvent having between one and ten carbon atoms. A phosphoric acid compound or in other words a phosphate is then separated from the solvent either in the form of concentrated phosphoric acid by evaporating the solvent, or in the form of a phosphate salt by adding a base to the extract and precipitating the phosphate salt.
Inventors
- 👤 Allen G Rubin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 06:18
CPC Classifications
C; C05; C05B; C05B7/00; C01; C01B; C01B25/00; C01B25/16; C01B25/18; C01B25/185; C01B25/234
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
48 words
The method of claim 1 wherein the water is incorporated in the digestion mixture before any substantial reaction has occurred between the phosphate rock and the ammonium bisulfate, and the digestion of such mixture is carried out at a temperature of between about 20* C. and 150* C.
Claim 2
Dependent Claim
42 words
The method of claim 1 wherein the phosphate rock and ammonium bisulfate are digested at a temperature between about 147* C. and 300* C., and the water is added to the digestion mixture after reaction between the phosphate rock and ammonium bisulfate.
Claim 3
Dependent Claim
30 words
The method of claim 1 wherein methanol is the solvent used to extract phosphoric acid from the ground product resulting from the digestion of phosphate rock, ammonium bisulfate and water.
Claim 4
Independent Claim
160 words
The method of obtaining an inorganic phosphate salt from phosphate rock which comprises: digesting a mixture of ground phosphate rock, molten ammonium bisulfate in an amount between about 4 and 9 parts by weight based upon the weight of phosphorous pentoxide in said rock, and water in an amount between about 5 and 16 percent by weight based upon the total weight of said mixture of phosphate rock, ammonium bisulfate and water; extracting phosphoric acid from the solid product resulting from such digestion by contacting said product with a solvent for phosphoric acid selected from the group consisting of alcohols and ketones having between one and 10 carbon atoms to dissolve such phosphoric acid in said solvent; and then precipitating an inorganic phosphate salt selected from the group consisting of ammonium phosphate, alkali metal phosphates and alkaline earth metal phosphates from the solution of phosphoric acid in said solvent by adding a base having a corresponding cation to said solution.
Claim 5
Dependent Claim
48 words
The method of claim 5 wherein the water is incorporated in the digestion mixture before any substantial reaction has occurred between the phosphate rock and the ammonium bisulfate, and the digestion of such mixture is carried out at a temperature of between about 20* C. and 150* C.
Claim 6
Dependent Claim
42 words
The method of claim 5 wherein the phosphate rock and ammonium bisulfate are digested at a temperature between about 147* C. and 300* C., and the water is added to the digestion mixture after reaction between the phosphate rock and ammonium bisulfate.
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) | 1975-01-17 | 1975-07-19 | 1976-01-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-01-17 | 1979-07-19 | 1980-01-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-01-17 | 1983-07-19 | 1984-01-18 | $7700.00 | Window Closed / Lapsed |