EP0227235A2
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EP
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Process of removing cationic impurities from wet process phosphoric acid
Assignee: IMC Fertilizer Inc
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Filing: 1986-10-15
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Granted: —
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Expires: 2006-10-15
Abstract
Abstract A method of removing aluminum, magnesium, iron and other impurities from wet process phosphoric acid is provided. The method comprises partially ammoniating the acid and reacting the acid with a fluoride ion donating compound to precipitate aluminum- and magnesium-containing ralstonite and ammonium fluorosilicate which can be easily separated from the acid thereby producing a partially ammoniated wet process phosphoric acid of reduced impurities content.
Inventors
- 👤 Dennis H. Michalski
- 👤 Viswanathan Srinivasan
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-28 10:40
CPC Classifications
C; C01; C01B; C01B25/00; C01B25/16; C01B25/18; C01B25/234; C01B25/237; C01B25/26; C01B25/28
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
62 words
A method for removing aluminum, magnesium and iron impurities from wet process phosphoric acid having a P₂O₅ content of about 17-54%, comprising the steps of: partially ammoniating the phosphoric acid; adding a fluoride ion donating compound to the acid to form a precipitate; separating the precipitate from the acid; and recovering a partially ammoniated wet process phosphoric acid of reduced impurity content.
Claim 2
Independent Claim
62 words
A method for removing aluminum, magnesium and iron impurities from wet process phosphoric acid having a P₂O₅ content of about 17-54%, comprising the steps of: partially ammoniating the phosphoric acid; adding a fluoride ion donating compound to the acid to form a precipitate; separating the precipitate from the acid; and recovering a partially ammoniated wet process phosphoric acid of reduced impurity content.
Claim 3
Dependent Claim
38 words
The method of claim 1 wherein the phosphoric acid has a P₂O₅ concentration of about 17 to 45% and a precipitate containing a fluorosilicate, an aluminum-, magnesium- and fluorine-containing ralstonite and an iron-, potassium- and ammonium-phosphate is formed.
Claim 4
Dependent Claim
15 words
The method as defined in claim 1, wherein the fluoride ion donating compound comprises HF.
Claim 5
Dependent Claim
27 words
The method as defined in claim 1, wherein the fluoride ion donating compound is selected from the group consisting of ammonium fluoride and ammonium bifluoride and both.
Claim 6
Dependent Claim
12 words
The method as defined in claim 2, wherein the ralstonite comprises NH₄MgAlF₆·H₂O.
Claim 7
Dependent Claim
14 words
The method as defined in claim 2, wherein the precipitated fluorosilicate comprises ammonium fluorosilicate.
Claim 8
Dependent Claim
14 words
The method as defined in claim 3, wherein the precipitated fluorosilicate comprises magnesium fluorosilicate.
Claim 9
Dependent Claim
27 words
The method as defined in claim 1, wherein the fluoride ion donating compound is selected from the group consisting of sodium fluoride, sodium bifluoride and mixtures thereof.
Claim 10
Dependent Claim
27 words
The method as defined in claim 1, wherein the fluoride ion donating compound is selected from the group consisting of potassium fluoride, potassium bifluoride and mixtures thereof.
Claim 11
Dependent Claim
22 words
The method as defined in claim 1, wherein the ammoniated phosphoric acid has an N/P mole ratio in the range of 0.2-1.0.
Claim 12
Dependent Claim
23 words
The method as defined in claim 10, wherein the ammoniated phosphoric acid preferably has an N/P mole ratio within the range of 0.2-0.3.
Claim 13
Dependent Claim
31 words
The method as defined in claim 1, wherein the fluoride ion added is in an amount of up to about 3.0 wt. % based upon the total weight of the acid.
Claim 14
Dependent Claim
21 words
The method as defined in claim 12, wherein the amount of fluoride ion added is up to about 1.5 wt. %.
Claim 15
Dependent Claim
20 words
The method as defined in claim 2, wherein the iron phosphate precipitate comprises a compound having the formula of Fe₃(K,NH₄)H₈(PO₄)₆·6H₂O.
Claim 16
Dependent Claim
26 words
The method as defined in claim 1, including the additional step of allowing the ammoniated phosphoric acid containing the added fluoride ion donating compound to settle.
Claim 17
Dependent Claim
18 words
The method as defined in claim 15, wherein the settling is conducted for up to about 8 hours.
Claim 18
Dependent Claim
21 words
The method as defined in claim 1, wherein the ammoniating step comprises sparging ammonia gas through the wet process phosphoric acid.
Claim 19
Dependent Claim
21 words
The method as defined in claim 1, wherein the ammoniating step comprises adding hydrous ammonia to the wet process phosphoric acid.
References Cited (Backward Citations)
No citation records indexed.
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