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 PDF

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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
Application number
EP95200958A
Other languages
English (en)
French (fr)
Inventor
D. J. Prof. Fray
G. Dr. Doughty
Christian Jean Marie E. C. Van Der Poorten
Jacky C. Dekeyser
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Vlaamse Instelling Voor Technologish Onderzoek NV VITO
Original Assignee
Vlaamse Instelling Voor Technologish Onderzoek NV VITO
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Vlaamse Instelling Voor Technologish Onderzoek NV VITO filed Critical Vlaamse Instelling Voor Technologish Onderzoek NV VITO
Publication of EP0688881A1 publication Critical patent/EP0688881A1/de
Ceased legal-status Critical Current

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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.

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  • 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)
EP95200958A 1994-05-09 1995-04-15 Verfahren zum Zusetzen von Natrium-Spuren zu Aluminium- oder Aluminium-Legierungsschmelzen Ceased EP0688881A1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
BE9400481 1994-05-09
BE9400481A BE1008380A3 (nl) 1994-05-09 1994-05-09 Werkwijze voor het toevoegen van sporen natrium aan een smelt van aluminium of een aluminiumlegering.

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)

* Cited by examiner, † Cited by third party
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)

* Cited by examiner, † Cited by third party
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

Patent Citations (2)

* Cited by examiner, † Cited by third party
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)

* Cited by examiner, † Cited by third party
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)

* Cited by examiner, † Cited by third party
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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