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US3764657A Expired / Lapsed US ⏱️ 0.0 years remaining

Process for removal of cationic impurities from technical grade phosphoric acid

Assignee: Chemische Fabrik Budenhiem KG
•
Filing: 1971-09-21
•
Granted: 1973-10-09
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Expires: 1991-09-21
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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

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-10-28 18:34
CPC Classifications
C; C01; C01B; C01B25/00; C01B25/16; C01B25/46; C01B25/461; C01B25/462

Claims Analysis

Total Claims: 5
Claim 1
Independent Claim 19 words
The process as defined in claim 1 wherein the organic solvent added is less than about 30 volume percent.
Claim 2
Dependent Claim 14 words
The process as defined in claim 1 wherein isopropanol is said water soluble alcohol.
Claim 3
Dependent Claim 19 words
The process as defined in claim 1 wherein the alkali ion is introduced in the form of gaseous ammonia.
Claim 4
Dependent Claim 16 words
The process as defined in claim 1 wherein the alkali ion is introduced is ammonium hydroxide.
Claim 5
Dependent Claim 20 words
The process as defined in claim 1 wherein the alkali ion is introduced in the form of an ammonium salt.

References Cited (Backward Citations)

US1929441A Cited
GB464370A Cited
US3650691A Cited

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

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