US4557915A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Production of phosphoric acid
Assignee: Rhone Poulenc Chimie de Base SA
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Filing: 1984-07-05
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Granted: 1985-12-10
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Expires: 2004-07-05
Abstract
Abstract Phosphoric acid is produced, with concomitant recovery of solids comprising compounds of fluorine and silica, by (i) acidulating a first amount of phosphate ore with a strong acid to produce a first phosphoric acid slurry, (ii) filtering said first slurry to separate the liquid phosphoric acid content therefrom, (iii) concentrating a fraction of the phosphoric acid thus separated, (iv) recovering same, and (v) condensing the evolved vapors of concentration with a liquid absorbent to produce a solution of fluosilicic acid, (vi) acidulating a second amount of phosphate ore with said solution of fluosilicic acid together with a fraction of said first slurry, or together with a fraction of the phosphoric acid separated in the step (ii), to produce a second phosphoric acid slurry, (vii) filtering said second slurry to separate both the liquid phosphoric acid content and a solids fraction therefrom, said solids fraction comprising fluorine and silica compounds, (viiia) recycling the phosphoric acid thus separated from said second slurry to the step (i), or (viiib) combining same with the fraction of separated phosphoric acid to be downstream concentrated in the step (iii).
Inventors
- 👤 Guy Nineuil
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 17:33
CPC Classifications
C; C01; C01B; C01B25/00; C01B25/16; C01B25/18; C01B25/22; C01B25/222; C01B25/232; C01B25/223; C01B25/225; C01B25/2208
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
182 words
A process for the production of phosphoric acid, comprising (a) acidulating a first amount of phosphate ore with a strong acid to produce a first phosphoric acid slurry, (b) filtering said first slurry to separate the liquid phosphoric acid content therefrom, (c) concentrating a fraction of the phosphoric acid thus separated, (d) recovering same, and (e) condensing the evolved vapors of concentration with a liquid absorbent to produce a solution of fluosilicic acid, (f) acidulating a second amount of phosphate ore with said solution of fluosilicic acid together with a fraction of said first slurry, or together with a fraction of the phosphoric acid separated in the step (b), to produce a second phosphoric acid slurry, (g) filtering said second slurry to separate both the liquid phosphoric acid content and a solids fraction therefrom, said solids fraction comprising fluorine and silica compounds essentially in the form of chukhrovite, and (h) recycling the phosphoric acid thus separated from said second slurry to the step (i) and combining same with the fraction of separated phosphoric acid to be downstream concentrated in the step (a).
Claim 2
Dependent Claim
182 words
A process for the production of phosphoric acid, comprising (a) acidulating a first amount of phosphate ore with a strong acid to produce a first phosphoric acid slurry, (b) filtering said first slurry to separate the liquid phosphoric acid content therefrom, (c) concentrating a fraction of the phosphoric acid thus separated, (d) recovering same, and (e) condensing the evolved vapors of concentration with a liquid absorbent to produce a solution of fluosilicic acid, (f) acidulating a second amount of phosphate ore with said solution of fluosilicic acid together with a fraction of said first slurry, or together with a fraction of the phosphoric acid separated in the step (b), to produce a second phosphoric acid slurry, (g) filtering said second slurry to separate both the liquid phosphoric acid content and a solids fraction therefrom, said solids fraction comprising fluorine and silica compounds essentially in the form of chukhrovite, and (h) recycling the phosphoric acid thus separated from said second slurry to the step (i) and combining same with the fraction of separated phosphoric acid to be downstream concentrated in the step (a).
Claim 3
Dependent Claim
16 words
The process as defined by claim 1, wherein the step (a) acidulation is with sulfuric acid.
Claim 4
Dependent Claim
52 words
The process as defined by claim 1, wherein the step (f) acidulation is carried out such that the liquid phase of the reaction mixture has a ratio M n+ /PO 4 3- of about 0.1, wherein M is an alkali metal or an alkaline earth metal cation other than CaSO 4 .
Claim 5
Dependent Claim
48 words
The process as defined by claim 3, wherein the liquid phase of the reaction mixture has a content in fluorine, expressed as H 2 SiF 6 , of at least about 2%, and a content in respect of P 2 O 5 ranging from about 20% to 30%.
Claim 6
Dependent Claim
56 words
The process as defined by claim 1, further comprising admixing a fraction of the concentrated phosphoric acid recovered in the step (d) with the acids separated in the filtration steps (b) and (g), filtering said combined acids to separate the liquid phosphoric acid content therefrom, and concentrating the phosphoric acid thus separated in the step (c).
Claim 7
Dependent Claim
32 words
The process as defined by claim 5, wherein the acids separated in the steps (b) and (g) are first admixed, and the resulting admixture is then combined with said concentrated phosphoric acid.
Claim 8
Dependent Claim
23 words
The process as defined by claim 5, the filtration step (g) and the filtering of the combined acids being through the same filter.
Claim 9
Dependent Claim
19 words
The process as defined in claim 1, comprising adding aluminum to the medium of acidulation in the step (f).
Claim 10
Dependent Claim
14 words
The process as defined by claim 1, comprising recovering chukhrovite from the step (g).
Claim 11
Dependent Claim
19 words
The process as defined by claim 1, comprising desupersaturating and settling concentrated phosphoric acid recovered in the step (d).
Claim 12
Dependent Claim
167 words
A process for the production of phosphoric acid, comprising (a) acidulating a first amount of phosphate ore with a strong acid to produce a first phosphoric acid slurry, (b) filtering said first slurry to separate the liquid phosphoric acid content therefrom, (c) concentrating a fraction of the phosphoric acid thus separated, (d) recovering same, and (e) condensing the evolved vapors of concentration with a liquid absorbent to produce a solution of fluosilicic acid, (f) acidulating a second amount of phosphate ore with said solution of fluosilicic acid together with a fraction of said first slurry, or together with a fraction of the phosphoric acid separated in the step (b), to produce a second phosphoric acid slurry, (g) filtering said second slurry to separate both the liquid phosphoric acid content and a solids fraction therefrom, said solids fraction comprising fluorine and silica compounds essentially in the form of chukhrovite, and (h) combining same with the fraction of separated phosphoric acid to be downstream concentrated in the step (a).
Claim 13
Dependent Claim
167 words
A process for the production of phosphoric acid, comprising (a) acidulating a first amount of phosphate ore with a strong acid to produce a first phosphoric acid slurry, (b) filtering said first slurry to separate the liquid phosphoric acid content therefrom, (c) concentrating a fraction of the phosphoric acid thus separated, (d) recovering same, and (e) condensing the evolved vapors of concentration with a liquid absorbent to produce a solution of fluosilicic acid, (f) acidulating a second amount of phosphate ore with said solution of fluosilicic acid together with a fraction of said first slurry, or together with a fraction of the phosphoric acid separated in the step (b), to produce a second phosphoric acid slurry, (g) filtering said second slurry to separate both the liquid phosphoric acid content and a solids fraction therefrom, said solids fraction comprising fluorine and silica compounds essentially in the form of chukhrovite, and (h) combining same with the fraction of separated phosphoric acid to be downstream concentrated in the step (a).
Claim 14
Dependent Claim
16 words
The process as defined by claim 11, wherein the step (a) acidulation is with sulfuric acid.
Claim 15
Dependent Claim
52 words
The process as defined by claim 11, wherein the step (f) acidulation is carried out such that the liquid phase of the reaction mixture has a ratio M n+ /PO 4 3- of about 0.1, wherein M is an alkali metal or an alkaline earth metal cation other than CaSO 4 .
Claim 16
Dependent Claim
48 words
The process as defined by claim 13, wherein the liquid phase of the reaction mixture has a content in fluorine, expressed as H 2 SiF 6 , of at least about 2%, and a content in respect of P 2 O 5 ranging from about 20% to 30%.
Claim 17
Dependent Claim
56 words
The process as defined by claim 11, further comprising admixing a fraction of the concentrated phosphoric acid recovered in the step (d) with the acids separated in the filtration steps (b) and (g), filtering said combined acids to separate the liquid phosphoric acid content therefrom, and concentrating the phosphoric acid thus separated in the step (c).
Claim 18
Dependent Claim
32 words
The process as defined by claim 15, wherein the acids separated in the steps (b) and (g) are first admixed, and the resulting admixture is then combined with said concentrated phosphoric acid.
Claim 19
Dependent Claim
23 words
The process as defined by claim 15, the filtration step (g) and the filtering of the combined acid being through the same filter.
Claim 20
Dependent Claim
19 words
The process as defined by claim 11, comprising adding aluminum to the medium of acidulation in the step (f).
Claim 21
Dependent Claim
14 words
The process as defined by claim 11, comprising recovering chukhrovite from the step (g).
Claim 22
Dependent Claim
19 words
The process as defined by claim 11, comprising desupersaturating and settling concentrated phosphoric acid recovered in the step (d).
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-12-09 | 1989-06-10 | 1989-12-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-12-09 | 1993-06-10 | 1993-12-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-12-09 | 1997-06-10 | 1997-12-10 | $7700.00 | Window Closed / Lapsed |