Recovery rate of chromium from stainless slag by iron melts

The kinetic behavior of Cr₂O₃ reduction by iron melts containing carbon, aluminum and silicon were investigated at various conditions in order to understand effective slag treatment for recovery of chromium from stainless slag. It was found that the recovery rate of chromium was fairly slow, but it was considerably accelerated by the addition of some fluxes, such as Al₂O₃ and SiO₂ to the slag, which promoted the formation of liquid slag at the early stage of the reaction, and the recovery ratio of chromium was also improved. In addition, SiO ₂ addition was more effective for increasing the chromium recovery than Al₂O₃ addition due to the effect of CaO/SiO ₂ ratio of slag on the reduction rate of Cr₂O₃ in slag. The experimental results were well simulated by the previous kinetic reaction model based on two-film theory, The modeling study showed that the transfer rate of chromium from slag to metal was controlled by the mass transport in the slag phase.