Thermodynamic analysis of contamination by alloying elements in aluminum recycling

Kenichi Nakajima, Osamu Takeda, Takahiro Miki, Kazuyo Matsubae, Shinichiro Nakamura, Tetsuya Nagasaka

    Research output: Contribution to journalArticle

    63 Citations (Scopus)

    Abstract

    In previous studies on the physical chemistry of pyrometallurgical processing of aluminum scrap, only a limited number of thermodynamic parameters, such as the Gibbs free energy change of impurity reactions and the variation of activity of an impurity in molten aluminum, were taken into account. In contrast, in this study we thermodynamically evaluated the quantitative removal limit of impurities during the remelting of aluminum scrap; all relevant parameters, such as the total pressure, the activity coefficient of the target impurity, the temperature, the oxygen partial pressure, and the activity coefficient of oxidation product, were considered. For 45 elements that usually occur in aluminum products, the distribution ratios among the metal, slag, and gas phases in the aluminum remelting process were obtained. Our results show that, except for elements such as Mg and Zn, most of the impurities occurred as troublesome tramp elements that are difficult to remove, and our results also indicate that the extent to which the process parameters such as oxygen partial pressure, temperature, and flux composition can be changed in aluminum production is quite limited compared to that for iron and copper production, owing to aluminum's relatively low melting point and strong affinity for oxygen. Therefore, the control of impurities in the disassembly process and the quality of scrap play important roles in suppressing contamination in aluminum recycling.

    Original languageEnglish
    Pages (from-to)5594-5600
    Number of pages7
    JournalEnvironmental Science and Technology
    Volume44
    Issue number14
    DOIs
    Publication statusPublished - 2010 Jul 15

    Fingerprint

    Alloying elements
    Aluminum
    Recycling
    Contamination
    recycling
    aluminum
    thermodynamics
    Thermodynamics
    Impurities
    Remelting
    activity coefficient
    Activity coefficients
    Oxygen
    partial pressure
    Partial pressure
    oxygen
    Physical chemistry
    Gibbs free energy
    analysis
    contamination

    ASJC Scopus subject areas

    • Chemistry(all)
    • Environmental Chemistry

    Cite this

    Thermodynamic analysis of contamination by alloying elements in aluminum recycling. / Nakajima, Kenichi; Takeda, Osamu; Miki, Takahiro; Matsubae, Kazuyo; Nakamura, Shinichiro; Nagasaka, Tetsuya.

    In: Environmental Science and Technology, Vol. 44, No. 14, 15.07.2010, p. 5594-5600.

    Research output: Contribution to journalArticle

    Nakajima, Kenichi ; Takeda, Osamu ; Miki, Takahiro ; Matsubae, Kazuyo ; Nakamura, Shinichiro ; Nagasaka, Tetsuya. / Thermodynamic analysis of contamination by alloying elements in aluminum recycling. In: Environmental Science and Technology. 2010 ; Vol. 44, No. 14. pp. 5594-5600.
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