US3870786A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Removal of phosphate compounds from fluoride containing solutions
Assignee: Individual
•
Filing: 1973-03-26
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Granted: 1975-03-11
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Expires: 1993-03-26
Abstract
Abstract A process for removing phosphate compounds such as phosphoric anhydride (P2O5) from fluoride containing solutions such as dilute hydrofluoric acid (HF) or fluosilicic acid (H2SiF6) is disclosed. This process involves the precipitation of aluminum phosphate (AlPO4) from the acidic fluoride containing solutions. The precipitation is brought about by the addition of an aluminum salt such as aluminum fluoride (AlF3), aluminum chloride hydrate (AlCl3.6H2O), aluminum nitrate (Al(NO3)3.9H2O), aluminum sulfate (Al(SO4)3.13-1/2H2O), aluminum ammonium sulfate (Al2(SO4)3.(NH4)2SO4.24H2O) and triammonium aluminum hexafluoride ((NH4)3AlF6). The pH is then adjusted to at least about 3 and the phosphoric anhydride is removed by precipitation.
Inventors
- 👤 Gustave E Kidde
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 21:22
CPC Classifications
C; C01; C01B; C01B33/00; C01B33/08; C01B33/10; C01B33/103; C01B7/00; C01B7/19; C01B7/191
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
73 words
A PROCESS FOR THE REMOVAL OF PHOSPHATE CONTAMINANTS FROM IMPURE FLUOSILICIC ACID AND HYDROFLUROIC ACID AQUEOUS SOLUTIONS HAVING A PH OF LESS THAN 2.6 COMPRISING: ADDING TO SAID SOLUTION A WATER SOLUBLE ALUMINUM SALT IN AN AMOUNT SUFFICIENT TO PRECIPITATE AN PHOSPHATE CONTAMINANTS AS ALLUMINUM PHOSPHATE; DECREASING THE ACIDITY OF SAID SOLUTION TO A PH OF AT LEAST 2.6 TO 3.1; AND SEPARATING THE RESULTING PRECIPITATE FROM THE RESULTING PHOSPHATE CONTAMINANT FREE SOLUTION.
Claim 2
Dependent Claim
73 words
A PROCESS FOR THE REMOVAL OF PHOSPHATE CONTAMINANTS FROM IMPURE FLUOSILICIC ACID AND HYDROFLUROIC ACID AQUEOUS SOLUTIONS HAVING A PH OF LESS THAN 2.6 COMPRISING: ADDING TO SAID SOLUTION A WATER SOLUBLE ALUMINUM SALT IN AN AMOUNT SUFFICIENT TO PRECIPITATE AN PHOSPHATE CONTAMINANTS AS ALLUMINUM PHOSPHATE; DECREASING THE ACIDITY OF SAID SOLUTION TO A PH OF AT LEAST 2.6 TO 3.1; AND SEPARATING THE RESULTING PRECIPITATE FROM THE RESULTING PHOSPHATE CONTAMINANT FREE SOLUTION.
Claim 3
Dependent Claim
73 words
A process for the removal of phosphate contaminants from impure fluosilicic acid and hydrofluoric acid aqueous solutions having a pH of less than 2.6 comprising: adding to said solution a water soluble aluminum salt in an amount sufficient to precipitate any phosphate contaminants as aluminum phosphate; decreasing the acidity of said solution to a pH of at least 2.6 to 3.1; and separating the resulting precipitate from the resulting phosphate contaminant free solution.
Claim 4
Dependent Claim
73 words
A process for the removal of phosphate contaminants from impure fluosilicic acid and hydrofluoric acid aqueous solutions having a pH of less than 2.6 comprising: adding to said solution a water soluble aluminum salt in an amount sufficient to precipitate any phosphate contaminants as aluminum phosphate; decreasing the acidity of said solution to a pH of at least 2.6 to 3.1; and separating the resulting precipitate from the resulting phosphate contaminant free solution.
Claim 5
Dependent Claim
13 words
The process of claim 1 wherein said water soluble aluminum salt is AlF3.
Claim 6
Dependent Claim
11 words
The process of claim 1 wherein the aluminum salt is AlCl3.6H2O.
Claim 7
Dependent Claim
13 words
The process of claim 1 wherein the aluminum salt is Al2(SO4)3.13- 1/2 H2O.
Claim 8
Dependent Claim
11 words
The process of claim 1 wherein the aluminum salt is Al2(SO4)3.(NH4)2SO4.24H2O.
Claim 9
Dependent Claim
11 words
The process of claim 1 wherein the aluminum salt is (NH4)3AlF6.
Claim 10
Dependent Claim
12 words
The process of claim 1 wherein said solution is neutralized by ammoniation.
Claim 11
Dependent Claim
117 words
A process for the removal of phosphoric anhydride from aqueous solutions of acidic fluorine containing compounds selected from the group consisting of fluosilicic acid (H2SiF6) and hydrofluoric acid (HF) said solution having a pH of less than 2.6 comprising: adding a water soluble aluminum salt to said solutions in an amount sufficient to precipitate any phosphoric anhydride as aluminum phosphate, said salt being selected from the group consisting of aluminum fluoride (AlF3), aluminum chloride hydrate (AlCl3.6H2O), aluminum nitrate (Al(NO3)3.9H2O), aluminum sulfate (Al(SO4)3.13- 1/2 H2O), aluminum ammonium sulfate (Al2(SO4)3.(NH4)2SO4.24H2O) and triammonium aluminum hexafluoride ((NH4)3AlF6); decreasing the acidity of said solution to a pH of at least about 3: and separating the resulting precipitate from the resulting purified solution.
Claim 12
Dependent Claim
117 words
A process for the removal of phosphoric anhydride from aqueous solutions of acidic fluorine containing compounds selected from the group consisting of fluosilicic acid (H2SiF6) and hydrofluoric acid (HF) said solution having a pH of less than 2.6 comprising: adding a water soluble aluminum salt to said solutions in an amount sufficient to precipitate any phosphoric anhydride as aluminum phosphate, said salt being selected from the group consisting of aluminum fluoride (AlF3), aluminum chloride hydrate (AlCl3.6H2O), aluminum nitrate (Al(NO3)3.9H2O), aluminum sulfate (Al(SO4)3.13- 1/2 H2O), aluminum ammonium sulfate (Al2(SO4)3.(NH4)2SO4.24H2O) and triammonium aluminum hexafluoride ((NH4)3AlF6); decreasing the acidity of said solution to a pH of at least about 3: and separating the resulting precipitate from the resulting purified solution.
Claim 13
Dependent Claim
15 words
The process of claim 8 wherein the pH is adjusted by the addition of ammonia.
Claim 14
Dependent Claim
79 words
A process for the removal of phosphoric anhydride from aqueous solutions of acidic fluorine containing compounds selected from the group consisting of fluosilicic acid (H2SiF6) and hydrofluoric acid (HF) said solution having a pH of less than 2.6 comprising: adding aluminum fLuoride (AlF3) in an amount sufficient to precipitate any phosphoric anhydride as aluminum phosphate; decreasing the acidity of said solution to a pH of at least about 3; and separating the resulting precipitate from the resulting purified solution.
Claim 15
Dependent Claim
79 words
A process for the removal of phosphoric anhydride from aqueous solutions of acidic fluorine containing compounds selected from the group consisting of fluosilicic acid (H2SiF6) and hydrofluoric acid (HF) said solution having a pH of less than 2.6 comprising: adding aluminum fLuoride (AlF3) in an amount sufficient to precipitate any phosphoric anhydride as aluminum phosphate; decreasing the acidity of said solution to a pH of at least about 3; and separating the resulting precipitate from the resulting purified solution.
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) | 1978-03-10 | 1978-09-09 | 1979-03-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-03-10 | 1982-09-09 | 1983-03-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-03-10 | 1986-09-09 | 1987-03-11 | $7700.00 | Window Closed / Lapsed |