EP0066988A2 - Procédé de récupération de l'uranium - Google Patents
Procédé de récupération de l'uranium Download PDFInfo
- Publication number
- EP0066988A2 EP0066988A2 EP82302566A EP82302566A EP0066988A2 EP 0066988 A2 EP0066988 A2 EP 0066988A2 EP 82302566 A EP82302566 A EP 82302566A EP 82302566 A EP82302566 A EP 82302566A EP 0066988 A2 EP0066988 A2 EP 0066988A2
- Authority
- EP
- European Patent Office
- Prior art keywords
- coprecipitate
- uranium
- leachate
- nitric acid
- silicate
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B60/00—Obtaining metals of atomic number 87 or higher, i.e. radioactive metals
- C22B60/02—Obtaining thorium, uranium, or other actinides
- C22B60/0204—Obtaining thorium, uranium, or other actinides obtaining uranium
- C22B60/0217—Obtaining thorium, uranium, or other actinides obtaining uranium by wet processes
- C22B60/0221—Obtaining thorium, uranium, or other actinides obtaining uranium by wet processes by leaching
- C22B60/0226—Obtaining thorium, uranium, or other actinides obtaining uranium by wet processes by leaching using acidic solutions or liquors
- C22B60/0239—Obtaining thorium, uranium, or other actinides obtaining uranium by wet processes by leaching using acidic solutions or liquors nitric acid containing ion as active agent
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B60/00—Obtaining metals of atomic number 87 or higher, i.e. radioactive metals
- C22B60/02—Obtaining thorium, uranium, or other actinides
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B60/00—Obtaining metals of atomic number 87 or higher, i.e. radioactive metals
- C22B60/02—Obtaining thorium, uranium, or other actinides
- C22B60/0204—Obtaining thorium, uranium, or other actinides obtaining uranium
- C22B60/0217—Obtaining thorium, uranium, or other actinides obtaining uranium by wet processes
- C22B60/0252—Obtaining thorium, uranium, or other actinides obtaining uranium by wet processes treatment or purification of solutions or of liquors or of slurries
- C22B60/026—Obtaining thorium, uranium, or other actinides obtaining uranium by wet processes treatment or purification of solutions or of liquors or of slurries liquid-liquid extraction with or without dissolution in organic solvents
Definitions
- This invention relates to recovering uranium from a silicate-uranium coprecipitate.
- a waste stream is produced which contains uranium, fluoride, ammonium, and nitrate ions.
- a calcium hydroxide or lime slurry is added which precipitates calcium fluoride.
- the ammonium diuranate waste stream is processed in an ammonia stripping column and the calcium fluoride slurry is sent to settling lagoons were excess water is decanted and run off. Some of the uranium remains in the calcium fluoride slurry as insoluble calcium uranate.
- the calcium uranate waste creates an expensive disposal problem and is a loss of a valuable resource.
- the quantity of uranium contaminated waste can be reduced by adding sodium silicate to the uranium waste stream prior to the addition of calcium hydroxide or lime as is described in Japanese Patent Specification No. 48-38320. This results in a silicate-uranium coprecipitate of significantly less volume than the calcium fluoride precipitate. The silicate-uranium coprecipitate is then disposed of by storage in drums.
- the present invention resides in a method of recovering uranium from a silicate-uranium coprecipitate which comprises leaching said coprecipitate with a leachate having a pH of from 2 to 3 followed by filtering said coprecipitate.
- uranium recovered that would otherwise be wasted, but it is recovered in a form which can be processed in a standard solvent extraction cycle. Moreover, if desired, sufficient uranium can be removed from the coprecipitate to permit its disposal as a non-nuclear waste material.
- a silicate-uranium coprecipitate is typically formed by adding a solution of water glass to an ammonium fluoride solution containing uranium in order to concentrate the uranium in the coprecipitate.
- a typical coprecipitate may contain about 15% (all percentages herein are by weight) by weight sodium silicate, about 85% water, and from 1,000 to 30,000 parts per million (ppm) of uranium, probably in the form of a uranyl silicate.
- the typical coprecipitate is a toothpaste-like solid containing large amounts of bound water.
- the invention will work with any silicate-uranium coprecipitate containing virtually any amount of uranium. It is preferable to wash the coprecipitate first in order to minimize the fluoride content in it as fluorides tend to attack silicates and increase their dissolution, thus reducing the degree of separation of the uranium.
- the first step involves lowering the pH of the coprecipitate to from 2 to 3. It has been found that this pH range is essential to the successful operation of the invention because below a pH of 2 the silica begins to dissolve which interferes with the subsequent solvent extraction of the uranium from the filtrate, and above a pH of 3, the uranium is not solubilized. The optimum pH has been found to be about 2.3.
- the leachate is an inorganic acid which can solubilize the uranium within the specified pH range.
- Nitric acid is the preferred leachate as it has been found to work very well and it is compatible with the processes which follow the process of this invention, but hydrochloric or sulfuric acid could also be used if desired. If a nitric acid leachate is used, it is preferably from 5 to 20% aqueous nitric acid.
- the weight ratio of coprecipitate to leachate is preferably from 1:1 to 3:1.
- the leachate After the leachate has been mixed with the coprecipitate, it is desirable to filter as soon as possible, preferably within one-half hour, as the silica will gradually dissolve in the leachate and silica which does not dissolve will become hydrolyzed and difficult to filter.
- the wash is preferably performed with from 5 to 20% aqueous nitric acid. From 4 to 7 washes are usually satisfactory as fewer washes will leave uranium behind in the coprecipitate and more washes will dilute the filtrate and dissolve more silica.
- the weight ratio of coprecipitate to each wash is preferably from 0.5:1 to 1.5:1 as less wash will not recover all the uranium that could be recovered and more wash will dilute the filtrate.
- the uranium in the filtrate can be recovered by any of a variety of well-known techniques.
- the preferred technique is solvent extraction using an organic extractant containing di-2-ethylhexyl phosphoric acid and trioctyl phosphine oxide (DEPA-TOPO) as that method is very effective.
- DEPA-TOPO trioctyl phosphine oxide
- a silicate uranium coprecipitate was mixed with a nitric acid leachate in a leach tank. After filtering, for example, in a pressurized rotary filter, a wash was used which resulted in a liquid filtrate, leaving behind the solids.
- a silicate uranium coprecipitate was prepared by mixing two compositions.
- the first composition contained 2% ammonium fluoride, 4% ammonia (added as ammonium hydroxide), 91% water, and 15 ppm uranium (added as uranyl nitrate).
- the second composition contained 6% silica (added as sodium silicate) and the remainder water. Ninety-nine parts of the first composition were mixed with one part of the second composition and the mixture was stirred for one minute and filtered.
- Test No. 1 shows that this process will work well at nitric acid levels as high as 20%. However, since satisfactory results are obtained at 10% nitric acid (Test No. 4), the added nitric acid expense is not economically justified.
- Test No. 2 shows that not all of the uranium is recovered when the pH is too high.
- Test No. 3 shows that a low recovery is obtained with too much nitric acid, and the pH is too low.
- Test No. 4 shows that better results are obtained when the coprecipitate is washed to remove fluoride first.
- Test No. 5 shows that good results can be obtained even without washing to remove-fluoride if the nitric acid concentration is not too high.
- Test No. 6 shows that an increased leach solution to cake ratio dilutes the final uranyl nitrate stream.
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Geology (AREA)
- Manufacturing & Machinery (AREA)
- Environmental & Geological Engineering (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Manufacture And Refinement Of Metals (AREA)
- Inorganic Compounds Of Heavy Metals (AREA)
- Removal Of Specific Substances (AREA)
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US26667681A | 1981-05-22 | 1981-05-22 | |
US266676 | 1981-05-22 |
Publications (2)
Publication Number | Publication Date |
---|---|
EP0066988A2 true EP0066988A2 (fr) | 1982-12-15 |
EP0066988A3 EP0066988A3 (fr) | 1983-11-02 |
Family
ID=23015553
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP82302566A Withdrawn EP0066988A3 (fr) | 1981-05-22 | 1982-05-20 | Procédé de récupération de l'uranium |
Country Status (6)
Country | Link |
---|---|
EP (1) | EP0066988A3 (fr) |
JP (1) | JPS57200225A (fr) |
KR (1) | KR830010209A (fr) |
ES (1) | ES512465A0 (fr) |
YU (1) | YU109182A (fr) |
ZA (1) | ZA823094B (fr) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0433860A2 (fr) * | 1989-12-20 | 1991-06-26 | Westinghouse Electric Corporation | Procédé de récupération de métaux à partir de précipités de verre soluble |
CN105969987A (zh) * | 2016-06-16 | 2016-09-28 | 南华大学 | 放射性碱渣中铀的浸出方法 |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
KR101047985B1 (ko) * | 2010-11-26 | 2011-07-13 | 한국지질자원연구원 | 초음파를 이용한 고효율 우라늄 침출 방법 |
Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3394997A (en) * | 1965-04-12 | 1968-07-30 | Gen Electric | Method of preparing uranium diuranate |
JPS5327800A (en) * | 1976-08-25 | 1978-03-15 | Mitsubishi Metal Corp | Uranium or/and thorium removingand recovering method from soln. containing uranium or/and thorium |
JPS5692123A (en) * | 1979-12-25 | 1981-07-25 | Mitsubishi Metal Corp | Removing and recovering method for uranium and/or thorium from solution containing uranium and/or thorium |
JPS56109825A (en) * | 1980-02-01 | 1981-08-31 | Mitsubishi Metal Corp | Removing and recovering method for uranium and/or thorium from liquor containing uranium and/or thorium |
-
1982
- 1982-05-05 ZA ZA823094A patent/ZA823094B/xx unknown
- 1982-05-20 EP EP82302566A patent/EP0066988A3/fr not_active Withdrawn
- 1982-05-21 ES ES512465A patent/ES512465A0/es active Granted
- 1982-05-21 YU YU01091/82A patent/YU109182A/xx unknown
- 1982-05-22 KR KR1019820002262A patent/KR830010209A/ko unknown
- 1982-05-22 JP JP57087188A patent/JPS57200225A/ja active Pending
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3394997A (en) * | 1965-04-12 | 1968-07-30 | Gen Electric | Method of preparing uranium diuranate |
JPS5327800A (en) * | 1976-08-25 | 1978-03-15 | Mitsubishi Metal Corp | Uranium or/and thorium removingand recovering method from soln. containing uranium or/and thorium |
JPS5692123A (en) * | 1979-12-25 | 1981-07-25 | Mitsubishi Metal Corp | Removing and recovering method for uranium and/or thorium from solution containing uranium and/or thorium |
JPS56109825A (en) * | 1980-02-01 | 1981-08-31 | Mitsubishi Metal Corp | Removing and recovering method for uranium and/or thorium from liquor containing uranium and/or thorium |
Non-Patent Citations (3)
Title |
---|
Patent Abstracts of Japan Vol. 2, no. 66, 19 May 1978 Page 1196M78 & JP-A-53-27800 * |
Patent Abstracts of Japan Vol. 5, no. 160, 15 October 1981 & JP-A-56-92123 & US-A-4 349 513 (Cat. X,E) * |
Patent Abstracts of Japan Vol. 5, no. 184, 21 November 1981 & JP-A-56-109825 & US-A-4 338 286 (Cat. X,E) * |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0433860A2 (fr) * | 1989-12-20 | 1991-06-26 | Westinghouse Electric Corporation | Procédé de récupération de métaux à partir de précipités de verre soluble |
EP0433860A3 (en) * | 1989-12-20 | 1992-07-08 | Westinghouse Electric Corporation | Waterglass precipitate recovery process |
CN105969987A (zh) * | 2016-06-16 | 2016-09-28 | 南华大学 | 放射性碱渣中铀的浸出方法 |
CN105969987B (zh) * | 2016-06-16 | 2018-01-09 | 南华大学 | 放射性碱渣中铀的浸出方法 |
Also Published As
Publication number | Publication date |
---|---|
ZA823094B (en) | 1983-06-29 |
YU109182A (en) | 1985-03-20 |
KR830010209A (ko) | 1983-12-26 |
ES8403975A1 (es) | 1984-04-01 |
ES512465A0 (es) | 1984-04-01 |
EP0066988A3 (fr) | 1983-11-02 |
JPS57200225A (en) | 1982-12-08 |
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Legal Events
Date | Code | Title | Description |
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PUAI | Public reference made under article 153(3) epc to a published international application that has entered the european phase |
Free format text: ORIGINAL CODE: 0009012 |
|
AK | Designated contracting states |
Designated state(s): BE CH DE FR GB IT LI SE |
|
PUAL | Search report despatched |
Free format text: ORIGINAL CODE: 0009013 |
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AK | Designated contracting states |
Designated state(s): BE CH DE FR GB IT LI SE |
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KL | Correction list |
Free format text: 83/05 NEUDRUCK |
|
17P | Request for examination filed |
Effective date: 19840308 |
|
STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: THE APPLICATION HAS BEEN WITHDRAWN |
|
18W | Application withdrawn |
Withdrawal date: 19851216 |
|
RIN1 | Information on inventor provided before grant (corrected) |
Inventor name: LAHODA, EDWARD JEAN |