Reduction of chromium oxides in stainless steel dust

Abstract

The recovery of metal oxides from stainless steel dust using C (graphite), SiFe, and Al as reductants was investigated under various conditions. The apparent distribution ratio of Cr (L′_Cr ^m/s) in the recovered metal and residual slag phases was defined as the major performance metric. The results show that the recovery ratio of metals increases as the ratio of CaO:SiO₂ by mass in the residual slag increases to 1.17. The residual content of metals in the slag decreases as the Al₂O₃ content of the slag is increased from approximately 8wt% to 10wt%. The recovery ratio of Cr increases with increasing L′_Cr ^m/s, and a linear relationship between L′_Cr ^m/s and the activity coefficient ratio of CrO in the slag and the recovered metal phase is observed. The combination of C and SiFe or Al as the reducing agents reveals that Si is the more effective coreductant.

Keywords

stainless steel dust / chromium oxides / recovery / apparent distribution ratio / activity coefficient

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