US4387077A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for the recovery of substantially radium free calcium sulphate, yttrium and lanthanides, as well as calcium sulphate, yttrium and lanthanides obtained by this process
Assignee: Stamicarbon BV
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Filing: 1981-12-14
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Granted: 1983-06-07
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Expires: 2001-12-14
Abstract
Abstract Recovery of yttrium, lanthanides and radium free calcium sulphate in a phosphoric acid process by digesting phosphate rock with an excess of phosphoric acid in the presence of more than about 5 wt.% of SO 4 -ions calculated to the amount of phosphate rock, separating out the insoluble residue and recovering yttrium and lanthanides therefrom, precipitating calcium sulphate from the remaining solution with sulphuric acid and separating this calcium sulphate from the resulting phosphoric acid solution.
Inventors
- 👤 Cornelis A. M. Weterings
- 👤 Louis H. M. Ramakers
- 👤 Johannes A. Janssen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 15:30
CPC Classifications
C; C01; C01F; C01F11/00; C01F11/46; C01F17/00; C01F17/10; C01F17/17; C01F17/20; C01F17/206; C01F17/218; C01F17/224; C01F17/229; C01F17/235; C01F17/241; C01F17/276
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
131 words
Process for the recovery of substantially radium free calcium sulphate, yttrium and lanthanides in a phosphoric acid preparation process comprising the steps of, (a) digesting phosphate rock with an excess of phosphoric acid required for the formation of monocalciumphosphate in the presence of more than about 5% by weight of sulphate ions calculated in respect of the quantity of phosphate rock to form a digestion liquor comprising an insoluble residue and a monocalcium phosphate solution, (b) separating out said insoluble residue from said digestion liquor, (c) precipitating calcium sulphate from the monocalcium phosphate solution with sulphuric acid forming a calcium sulphate precipitate and a phosphoric acid solution, (d) separating said precipitated calcium sulphate from said phosphoric acid solution, and (e) separating yttrium and lanthanides from said insoluble residue of step (b).
Claim 2
Dependent Claim
131 words
Process for the recovery of substantially radium free calcium sulphate, yttrium and lanthanides in a phosphoric acid preparation process comprising the steps of, (a) digesting phosphate rock with an excess of phosphoric acid required for the formation of monocalciumphosphate in the presence of more than about 5% by weight of sulphate ions calculated in respect of the quantity of phosphate rock to form a digestion liquor comprising an insoluble residue and a monocalcium phosphate solution, (b) separating out said insoluble residue from said digestion liquor, (c) precipitating calcium sulphate from the monocalcium phosphate solution with sulphuric acid forming a calcium sulphate precipitate and a phosphoric acid solution, (d) separating said precipitated calcium sulphate from said phosphoric acid solution, and (e) separating yttrium and lanthanides from said insoluble residue of step (b).
Claim 3
Dependent Claim
31 words
Process in accordance with claim 1 wherein at least a portion of said phosphoric acid solution of step (d) is used in the digestion of said phosphate rock of step (a).
Claim 4
Dependent Claim
36 words
Process in accordance with claim 2 wherein at least a portion of said phosphoric acid solution of step (d) is settled forming a weak acid slurry and said slurry is used to digest the phosphate rock.
Claim 5
Dependent Claim
19 words
Process in accordance with claim 1 wherein sulphuric acid is present in step (a) to digest said phosphate rock.
Claim 6
Dependent Claim
26 words
Process in accordance with claim 1 wherein a reducing agent is added to at least one of, (i) said phosphate rock, and (ii) said digestion liquor.
Claim 7
Dependent Claim
22 words
Process in accordance with claim 5 wherein the said reducing agent is at least one of, powdered metallic iron, zinc or aluminum.
Claim 8
Dependent Claim
32 words
Process in accordance with claim 6 wherein the amount of said reducing agent is from about 0.25 to about 1.5% by weight calculated in respect of the amount of said phosphate rock.
Claim 9
Dependent Claim
17 words
Process in accordance with claim 1 wherein a flocculant is added intermediate to steps (a) and (b).
Claim 10
Dependent Claim
34 words
Process in accordance with claim 1 comprising the steps of (i) treating said residue of step (b) with acid to form an acid liquid and (ii) separating yttrium and lanthanides from said acid liquid.
Claim 11
Dependent Claim
30 words
Process in accordance with claim 9, wherein said acid liquid of step (i) is neutralized and said neutralized liquid is extracted with organic solvent to recover said yttrium and lanthanides.
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) | 1986-06-06 | 1986-12-06 | 1987-06-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-06-06 | 1990-12-06 | 1991-06-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-06-06 | 1994-12-06 | 1995-06-07 | $7700.00 | Window Closed / Lapsed |