Shear-force based stainless steel slag modification for chromium immobilization

Qing Zhao, Chengjun Liu, Longhu Cao, Maofa Jiang, Li Baokuan, Henrik Saxén, Ron Zevenhoven

    Research output: Contribution to journalArticleScientificpeer-review

    15 Citations (Scopus)

    Abstract

    Immobilization of chromium in a stable spinel by modification is a powerful way to prevent chromium pollution of stainless steel (SS) slags. The precipitated spinel grain size is usually smaller than 30 µm, however, which limits the effectiveness of the modification. In the literature, very few efforts have been reported on promotion of spinel growth rate by optimizing the dynamic conditions. In this study, the effects of shear force on the spinel grain size evolution under isothermal conditions and during cooling were investigated. The experimental results indicate that the employment of shear force significantly changes the growth behavior of spinel at 1500°C. The growth mechanism of spinel was studied by using crystal size distribution (CSD) theory, showing different regimes of supply-controlled Ostwald ripening, surface-controlled growth with decaying nucleation rate, and constant rate nucleation and growth at shear rates of 0 s−1, 10.83 s−1, and 21.67 s−1, respectively. On the other hand, at a cooling rate of 5°C·min−1, the shear force was found to have little effect on the crystallization behavior of spinel. The results of static leaching tests indicated that hardly any chromium had leached, which makes the modified SS slag more environmentally friendly when used as a raw material.

    Original languageUndefined/Unknown
    Pages (from-to)583–589
    JournalIsij International
    Volume59
    Issue number3
    DOIs
    Publication statusPublished - 2019
    MoE publication typeA1 Journal article-refereed

    Keywords

    • Steelmaking slag
    • chromium

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