EP0688881A1 - Verfahren zum Zusetzen von Natrium-Spuren zu Aluminium- oder Aluminium-Legierungsschmelzen - Google Patents
Verfahren zum Zusetzen von Natrium-Spuren zu Aluminium- oder Aluminium-Legierungsschmelzen Download PDFInfo
- Publication number
- EP0688881A1 EP0688881A1 EP95200958A EP95200958A EP0688881A1 EP 0688881 A1 EP0688881 A1 EP 0688881A1 EP 95200958 A EP95200958 A EP 95200958A EP 95200958 A EP95200958 A EP 95200958A EP 0688881 A1 EP0688881 A1 EP 0688881A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- sodium
- melt
- aluminium
- electrode
- solid
- 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.)
- Ceased
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Classifications
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25C—PROCESSES FOR THE ELECTROLYTIC PRODUCTION, RECOVERY OR REFINING OF METALS; APPARATUS THEREFOR
- C25C3/00—Electrolytic production, recovery or refining of metals by electrolysis of melts
- C25C3/02—Electrolytic production, recovery or refining of metals by electrolysis of melts of alkali or alkaline earth metals
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C21/00—Alloys based on aluminium
- C22C21/02—Alloys based on aluminium with silicon as the next major constituent
- C22C21/04—Modified aluminium-silicon alloys
Definitions
- the invention concerns a method for adding traces of sodium to a melt of aluminium or an aluminium alloy.
- traces of sodium should be understood amounts smaller than 1,000 ppm and usually even smaller than 150 to 200 ppm.
- the conventional manner for adding said sodium consists in throwing tablets of sodium which is vacuum-packed in aluminium and which thus contain relatively large amounts of sodium, for example 6 percent by weight, in the melt of aluminium or the aluminium alloy.
- the amount of sodium from the tablet which ends up in the melt is very small, however, in practice only about 0.05%. This can be explained in that the livid metal starts to bubble heavily as soon as the tablet is thrown in and a large amount of the sodium starts to oxidize when exposed to the air. Due to this sodium combustion there is much smoke development, which is environmentally harmful, and there is a great loss of sodium, as a result of which the output of this method is very low. Moreover, the amount of sodium which is absorbed in the melt will be gradually reduced as a result of the evaporation of sodium, so that a new tablet has to be thrown in regularly, and it will be difficult to determine the exact amount of sodium at a given moment.
- the invention aims to remedy these disadvantages and to provide a method for adding traces of sodium to the melt of aluminium or an aluminium alloy which is not only simple and ecologically sound, but which also consumes only a little amount of sodium and allows for an almost constant concentration of sodium in the aluminium.
- This aim is reached according to the invention by immersing an electrode in the melt of aluminium or the aluminium alloy which contains molten sodium or a molten sodium compound which is separated from the melt by a solid-state electrolyte conducting sodium ions, and by providing a direct voltage between said electrode and the melt.
- an additional electrode is provided in the melt, and a direct voltage is created between said additional electrode and the first-mentioned electrode.
- beta alumine or beta'' alumine is used as a solid-state electrolyte.
- the figure shows a vessel 1 filled with a melt 2 of aluminium or an aluminium alloy such as an aluminium-silicon alloy, at a temperature of about 750 ⁇ C.
- a first electrode 3 consists of molten sodium or a molten sodium compound 5 which, due to the temperature of the melt 2, has liquefied, and a of a nickel conductor 6 which sticks in the sodium or the sodium compound 5.
- This electrode 3 is contained in a tubular recipient of solid-state electrolyte 7 which is immersed for a large part in the melt 2.
- the other additional electrode 4 is a carbon electrode.
- This carbon electrode 4 and the conductor 6 are electrically connected to one another via a line 8 in which a current meter 9 and a DC source 10, for example a battery, are connected.
- a current meter 9 and a DC source 10 for example a battery
- a voltmeter 11 In the parallel circuit with the DC source is connected a voltmeter 11.
- NaOH can be used as a sodium compound, a sodium salt or a mixture of sodium salts such as sodium chloride, sodium carbonate, etc.
- solid-state electrolyte recipient 7 must be impermeable to the melt 2 and to the liquid sodium or the liquid sodium compound 5, but it must form a sodium ion conductor.
- a suitable solid-state electrolyte is beta alumine or beta'' alumine.
- the direct current which is created between the electrodes 3 and 4 depends on the construction as such and varies from a few volt to dozens of volt.
- the solid-state sodium or the solid-state sodium compound By immersing the solid-state electrolyte recipient 7 in the melt 2, the solid-state sodium or the solid-state sodium compound will liquefy due the heat of the melt 2, as a result of which Na+ ions and electrodes are formed.
- the sodium ions migrate through the solid-state electrolyte recipient 7 to the surface thereof which makes contact with the melt 2, as a result of which the ions are neutralized into sodium.
- the electrodes of the liquid sodium or the liquid sodium compound 5 flow via the line 8 to the carbon electrode 4 and thus into the melt 2 in order to neutralize the sodium ions.
- sodium is continuously provided into the melt 2, which results in sodium concentrations of up to 1,000 ppm and preferably of no more than 150 to 200 ppm.
- the above-described method is relatively simple and the loss of sodium is limited. This method offers a great efficiency and a minimal environmental impact and makes it possible to control the concentration of sodium with relatively much accuracy. Already as of a concentration of 10 to 30 ppm there is a clear improvement of the quality of the castings cast with the doped aluminium or the doped aluminium compound.
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Mechanical Engineering (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- Manufacture And Refinement Of Metals (AREA)
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
BE9400481A BE1008380A3 (nl) | 1994-05-09 | 1994-05-09 | Werkwijze voor het toevoegen van sporen natrium aan een smelt van aluminium of een aluminiumlegering. |
BE9400481 | 1994-05-09 |
Publications (1)
Publication Number | Publication Date |
---|---|
EP0688881A1 true EP0688881A1 (de) | 1995-12-27 |
Family
ID=3888151
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP95200958A Ceased EP0688881A1 (de) | 1994-05-09 | 1995-04-15 | Verfahren zum Zusetzen von Natrium-Spuren zu Aluminium- oder Aluminium-Legierungsschmelzen |
Country Status (2)
Country | Link |
---|---|
EP (1) | EP0688881A1 (de) |
BE (1) | BE1008380A3 (de) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO1999060180A1 (en) * | 1998-05-15 | 1999-11-25 | Foseco International Limited | Method and apparatus for the treatment of a melt |
US10326187B2 (en) * | 2014-04-29 | 2019-06-18 | Mahle International Gmbh | Anode and electrolyte for a metal-air battery |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0446152A1 (de) * | 1990-03-07 | 1991-09-11 | Aluminium Pechiney | Paket zum Einführen von Leichtmetall in Aluminiumlegierungsschmelze |
EP0497410A1 (de) * | 1991-01-29 | 1992-08-05 | "VLAAMSE INSTELLING VOOR TECHNOLOGISCH ONDERZOEK", afgekort "V.I.T.O." | Verfahren zur Änderung der Konzentration eines chemischen Elementes in einem flüssigen Metall auf elektrochemischem Wege |
-
1994
- 1994-05-09 BE BE9400481A patent/BE1008380A3/nl not_active IP Right Cessation
-
1995
- 1995-04-15 EP EP95200958A patent/EP0688881A1/de not_active Ceased
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0446152A1 (de) * | 1990-03-07 | 1991-09-11 | Aluminium Pechiney | Paket zum Einführen von Leichtmetall in Aluminiumlegierungsschmelze |
EP0497410A1 (de) * | 1991-01-29 | 1992-08-05 | "VLAAMSE INSTELLING VOOR TECHNOLOGISCH ONDERZOEK", afgekort "V.I.T.O." | Verfahren zur Änderung der Konzentration eines chemischen Elementes in einem flüssigen Metall auf elektrochemischem Wege |
Non-Patent Citations (2)
Title |
---|
DATABASE METADEX ASM/IOM; M.SUN ET AL: "ACTIVITY OF SODIUM IN LIQUID ALUMINIUM" * |
JOURNAL OF CENTRAL-SOUTH INSTITUTE OF MINING AND METALLURGY (CHINA), vol. 23, no. 1, pages 99 - 104 * |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO1999060180A1 (en) * | 1998-05-15 | 1999-11-25 | Foseco International Limited | Method and apparatus for the treatment of a melt |
US6599413B1 (en) | 1998-05-15 | 2003-07-29 | Foseco International Limited | Method and apparatus for the treatment of a melt |
US10326187B2 (en) * | 2014-04-29 | 2019-06-18 | Mahle International Gmbh | Anode and electrolyte for a metal-air battery |
Also Published As
Publication number | Publication date |
---|---|
BE1008380A3 (nl) | 1996-04-02 |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
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 |
Kind code of ref document: A1 Designated state(s): DE FR GB NL |
|
17P | Request for examination filed |
Effective date: 19960318 |
|
17Q | First examination report despatched |
Effective date: 19971110 |
|
STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: THE APPLICATION HAS BEEN REFUSED |
|
18R | Application refused |
Effective date: 19990311 |