US3872215A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Phosphate purification process
Assignee: BK Giulini Chemie GmbH
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Filing: 1971-06-16
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Granted: 1975-03-18
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Expires: 1991-06-16
Abstract
Abstract Crude phosphoric acid is mixed with an organic solvent or solvent mixture having the ability to absorb at least 9 weight-% water as based on solution weight. From this mixture, a water/phosphoric acid/solvent phase is withdrawn and mixed with an aqueous solution of NaOH in an amount equal to 1 to 40 weight% calculated as oxide and based on the amount required for producing NaH2PO4 from the phosphoric acid present in the water/phosphoric acid/solvent phase. Following this mixing, a water/phosphoric acid/solvent phase is withdrawn and mixed with an aqueous solution of NaOH in an amount for causing at least NaH2PO4 to pass from the water/phosphoric acid/solvent phase into an aqueous phase. The NaH2PO4 in this aqueous phase is a significantly purer form of P2O5 than was the initial crude acid.
Inventors
- 👤 Egon Cherdron
- 👤 Hans Joachim Forster
- 👤 Istvan Potencsik
- 👤 Manfred Haerter
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 14:57
CPC Classifications
C; C01; C01B; C01B25/00; C01B25/16; C01B25/46; C01B25/18; C01B25/234
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
229 words
A METHOD FOR PRODUCING PURE PHOSPHATE FROM CRUDE PHOSPHORIC ACID, COMPRISING THE STEPS OF: A. MIXING CRUDE PHOSPHORIC ACID WITH AN ALCOHOL OR ALCOHOL MIXTURE HAVING THE ABILITY TO ABSORB AT LEAST 9 WEIGHT-% WATER AS BASED ON SOLUTION WEIGHT AND WHICH FORMS A WATER/PHOSPHORIC ACID/ALCOHOL PHASE, THE VOLUME RATIO OF THE PHOSPHORIC ACID TO THE ALCOHOL BEING FROM THE RANGE 1:025 TO 1:20, IN THE PRESENCE OF AT LEAST ONE DISSOLVED ALKALI OR AMMONIUM COMPOUND, B. WITHDRAWING FROM STEP A) THE WATER/PHOSPHORIC ACID/SOLVENT PHASE, C. MIXING WITH THE WATER/PHOSPHORIC ACID/SOLVENT PHASE OF STEP B) AT LEAST ONE BASIC COMPOUND SELECTED FROM THE GROUP CONSISTING OF ALKALI OXIDES, ALKALI HYDROXIDES, ALKALI CARBONATES, ALKALI PHOSPHATES, AMMONIA, AMMONIA HYDROXIDES, AND AMMONIUM SALTS, IN AN AMOUNT EQUAL TO 1 TO 40 WEIGHT-% CALCULATED AS OXIDE AND BASED ON THE AMOUNT REQUIRED FOR PRODUCING MONOALKALI - OR MONOAMMONIUM-ORTHOPHOSPHATE FROM THE PHOSPHORIC ACID PRESENT IN SAID WATER/PHOSPHORIC ACID/SOLVENT PHASE THEREBY REMOVING INORGANIC IMPURITIES FROM SAID WATER/PHOSPHORIC ACID/SOLVENT PHASE, D. WITHDRAWING FROM STEP C) A PURER WATER/PHOSPHORIC ACID/SOLVENT PHASE, E. ADDING TO THE WATER/PHOSPHORIC ACID/SOLVENT PHASE OF STEP D) A BASIC COMPOUND FOR CAUSING AT LEAST THE SAID MONOORTHOPHOSPHATE TO PASS FROM SAID WATER/PHOSPHORIC ACID/SOLVENT PHASE OF STEP D) INTO AN AQUEOUS PHASE, AND F. RECOVERING SAID AQUEOUS PHASE CONTAINING SAID MONOORTHOPHOSPHATE, WHEREIN THE TEMPERATURE IN STEPS A) THROUGH E) IS FROM 5* TO 100*C.
Claim 2
Independent Claim
229 words
A METHOD FOR PRODUCING PURE PHOSPHATE FROM CRUDE PHOSPHORIC ACID, COMPRISING THE STEPS OF: A. MIXING CRUDE PHOSPHORIC ACID WITH AN ALCOHOL OR ALCOHOL MIXTURE HAVING THE ABILITY TO ABSORB AT LEAST 9 WEIGHT-% WATER AS BASED ON SOLUTION WEIGHT AND WHICH FORMS A WATER/PHOSPHORIC ACID/ALCOHOL PHASE, THE VOLUME RATIO OF THE PHOSPHORIC ACID TO THE ALCOHOL BEING FROM THE RANGE 1:025 TO 1:20, IN THE PRESENCE OF AT LEAST ONE DISSOLVED ALKALI OR AMMONIUM COMPOUND, B. WITHDRAWING FROM STEP A) THE WATER/PHOSPHORIC ACID/SOLVENT PHASE, C. MIXING WITH THE WATER/PHOSPHORIC ACID/SOLVENT PHASE OF STEP B) AT LEAST ONE BASIC COMPOUND SELECTED FROM THE GROUP CONSISTING OF ALKALI OXIDES, ALKALI HYDROXIDES, ALKALI CARBONATES, ALKALI PHOSPHATES, AMMONIA, AMMONIA HYDROXIDES, AND AMMONIUM SALTS, IN AN AMOUNT EQUAL TO 1 TO 40 WEIGHT-% CALCULATED AS OXIDE AND BASED ON THE AMOUNT REQUIRED FOR PRODUCING MONOALKALI - OR MONOAMMONIUM-ORTHOPHOSPHATE FROM THE PHOSPHORIC ACID PRESENT IN SAID WATER/PHOSPHORIC ACID/SOLVENT PHASE THEREBY REMOVING INORGANIC IMPURITIES FROM SAID WATER/PHOSPHORIC ACID/SOLVENT PHASE, D. WITHDRAWING FROM STEP C) A PURER WATER/PHOSPHORIC ACID/SOLVENT PHASE, E. ADDING TO THE WATER/PHOSPHORIC ACID/SOLVENT PHASE OF STEP D) A BASIC COMPOUND FOR CAUSING AT LEAST THE SAID MONOORTHOPHOSPHATE TO PASS FROM SAID WATER/PHOSPHORIC ACID/SOLVENT PHASE OF STEP D) INTO AN AQUEOUS PHASE, AND F. RECOVERING SAID AQUEOUS PHASE CONTAINING SAID MONOORTHOPHOSPHATE, WHEREIN THE TEMPERATURE IN STEPS A) THROUGH E) IS FROM 5* TO 100*C.
Claim 3
Dependent Claim
14 words
A method as claimed in claim 1, wherein said alcohol, is Isopropylalcohol or butylalcohol.
Claim 4
Dependent Claim
28 words
A method as claimed in claim 1, wherein said alcohol mixture is a mixture of isopropanol and at least one aliphatic alcohol having 4 to 9 carbon atoms.
Claim 5
Dependent Claim
28 words
A method as claimed in claim 1, the alkali content in step a) being, calculated as oxide, from 0.1 to 6 weight-% as based on the phosphoric acid.
Claim 6
Dependent Claim
38 words
A method as claimed in claim 1, wherein step c) is performed with an amount of said basic compound equal to 10 to 30 weight-%, calculated as alkali oxide and based on the amount required for producing mono-orthophosphate.
Claim 7
Dependent Claim
167 words
A method as claimed in claim 1, which further comprises: b''. withdrawing from step a) the aqueous phase; c''. mixing this aqueous phase of step b'') with at least an amount of sulfuric acid required to release as phosphoric acid the phosphate therein; d''. adding to the thus-treated aqueous phase of step c'') an alcohol or alcohol mixture capable of absorbing at least 9 weight-% water as based on solution weight for removing the thus-liberated phosphoric acid from the resulting sulfate-containing mixture and into a second solvent phase; e''. mixing said second solvent phase with the aqueous phase remaining after step d); f''. separating the resulting organic aqueous phases from one another; g''. mixing said organic phase from step f'') with at least one basic compound selected from the group consisting of alkali compounds, ammonia, ammonium hydroxide and ammonium salts for forming at least monoalkali or monoammonium orthophosphate; and h''. passing said aqueous phase from step B''), to a step for decomposing crude phosphate with sulfuric acid.
Claim 8
Dependent Claim
27 words
A method as claimed in claim 1, further comprising the steps of recovering said alcoholic solvent from step (e) and recycling the recovered solvent to step a).
Claim 9
Dependent Claim
15 words
A method as claimed in claim 1, wherein steps a) to e) are performed continuously.
Claim 10
Dependent Claim
29 words
A method as claimed in claim 1, further comprising, before step a), the step of extracting with a water-immiscible organic solvent organic immpurities present in said crude phosphoric acid.
Claim 11
Dependent Claim
30 words
A method as claimed in claim 9, wherein the waterimmiscible organic solvent in the step of extracting is at least one oxygen-containing organic compound having 5 to 20 carbon atoms.
Claim 12
Dependent Claim
40 words
A method as claimed in claim 10, wherein the waterimmiscible oxygen-containing organic solvent of the step of extracting contains at least one compound selected from the group consisting of aliphatic, aromatic and cyclic hydrocarbons having 6 to 20 carbon atoms.
Claim 13
Dependent Claim
23 words
A method as claimed in claim 11, wherein the volume ratio of hydrocarbon to oxygen-containing organic solvent amounts to from 0.1:1 to 10:1.
Claim 14
Dependent Claim
22 words
A method as claimed in claim 12, wherein the step of extracting is carried out at a temperature between 10* and 100*C.
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) | 1978-03-17 | 1978-09-16 | 1979-03-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-03-17 | 1982-09-16 | 1983-03-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-03-17 | 1986-09-16 | 1987-03-18 | $7700.00 | Window Closed / Lapsed |