Direct reduction of low grade chromite overburden for recovery of metals

The management of huge volumes of overburden at chromite mines is a concern, and there is a need to make effective use of this material. Therefore, direct reduction of low grade chromite overburden from the Sukinda chromite mines was studied at high temperatures to recover Fe, Cr and Ni. The effect of process parameters, such as temperature, time, reductant and flux, on the recovery of these metals was studied. The bench scale results obtained were then used in laboratory rotary hearth furnace reduction experiments, where it was found that a cycle time of 25 min is required for maximum recovery of metal. It was observed that similar to 90% of Fe and > 90% of Ni were recovered and thus have the potential to reduce the volume of waste at chromite mines.