Effect of Holding Time on Reduction of Stainless Steel Slag by FeSi

In view of the problem of the elution risk of Cr⁶⁺ that restrains utilization of stainless steel slag as raw material, combining with thermodynamics and dynamics principle of metallurgy, X-ray fluorescence spectrometer (XRF) and scanning electron microscope (SEM) were used to characterize the stainless steel slag samples. The effects of holding time at 1 550℃ on the occurrence of residual chromium and recovery rate of chromium in the stainless steel slag reduced with FeSi were investigated. The results show that under the condition of adding FeSi with mass fraction of 6%, the residual chromium content in the stainless steel slag gradually decreases with the increase of holding time, and the recovery rate of chromium increases gradually. When the holding time is kept from 5 min to 30 min, the recovery rate increases from 50.55% up to 86.05%. The residual chromium in the reduction slag exists in the form of metal particles, and with the extension of heating time, the number of metal particles decreases and the particle size increases.